Comments on: What is a Battery - A Complete Guide to Battery Basics

By: Ken Britton

Ken Britton — Tue, 02 Sep 2025 18:20:07 -0700

Great information thank you

By: Danielerozy

Danielerozy — Thu, 13 Mar 2025 15:11:52 -0700

Great news for all us

By: Steven

Steven — Thu, 19 Jan 2023 18:42:02 -0800

Just trying to understand the AGM batteries behavior. I have 8-6v batteries used for a small solar system of 48v. When charging the batteries get up to 57v, but when discharging they start out at 50v and then slowly discharge. Why does it start discharging at such a low voltage

By: Joslyn schicchi

Joslyn schicchi — Thu, 13 Oct 2022 22:08:58 -0700

I have a 2009 tao tao moped with a TPE Lithium Motorcycle Scooter Battery. im having issues getting it connected again when j do screw thevterminals in therss no power i also did charge after use

By: Steve Z

Steve Z — Thu, 07 Jul 2022 06:53:49 -0700

Does a deep cycle lead acid battery discharge faster than it charges? I ask because I am using an 80ah battery to power the small refrigerator in my camper when I’m boondocking. I have a 200w Solar suitcase and a 100 watt panel on the camper. Their controllers are often in a “float” or “full” state when the sun is out and the fridge is on - indicating the battery won’t take any more charge. But the battery monitor shows it is just at 60 or 70 percent capacity. Does this make sense? Thank you!

By: Carl Oh

Carl Oh — Wed, 29 Jun 2022 04:02:28 -0700

Hi great article…I have a TT with 2 trojan 6v batteries hooked up to a renogy 30amp controller and a lg 350 solar panel When I hooked them up at the beginning of year the hydrometer reading was 1265. Now the reading is 1225 but the controller says 100% 13.4v. I have been watching and the controller does boost and float and is always at 100%. Why is the hydrometer reading in the recharge area. The whole system is only 1 year old.

By: Albertnok

Albertnok — Mon, 22 Nov 2021 20:36:58 -0800

Bravo, seems to me, is a remarkable phrase

By: Alex

Alex — Mon, 01 Nov 2021 09:40:42 -0700

Do I need to disconnect battery banks to measure CCA? I have (2 x 12v in serie) x2 of this in parrallel. So basicaly 24v with 4 x 12v batteries.

By: Tim

Tim — Tue, 12 Oct 2021 19:57:17 -0700

I have a flat plate AGM Deep cycle 135aH battery. It's brand new and is sitting at 13 volts. I recently bought a load tester off ebay and when I go to load test the battery it is asking for the CCA. How do I calculate the CCA if the CCA is not displayed on the battery sticker? I assume the CCA is not displayed because this battery is not a cranking battery.

By: Andy Schouteten

Andy Schouteten — Sat, 09 Oct 2021 21:18:44 -0700

We have an off gritt solar system that supports a home with 240v electricity for fridge, dishwasher, washing machine and all lighting. We have around 3kw of solar panels and a 2,5 kw inverter. We store electricity in 24 6v 225ah lion batteries. We are thinking of replacing these batteries because they are more than 10 years old. We also would like to reduce the number of batteries but still have the same or better storage capacity. What would be your recommendations

By: Jim Navotney

Jim Navotney — Tue, 05 Oct 2021 16:37:49 -0700

And despite all the youtube videos never runn your engine with the car battery dissconnected

By: Eileen McCracken

Eileen McCracken — Sun, 19 Sep 2021 09:00:04 -0700

This is helpful. For the existing deep cell in our rv we should not use more than 50% of charge. If we upgrade to agm can we use more? Reading the article there are a lot of maintenance and life span advantages but I’m not clear if I can run my fridge longer! Thanks so much

By: Dhika R

Dhika R — Sun, 10 May 2020 18:03:14 -0700

I've got a 100 ah battery (i'm told by the ebay seller its gel) that has a maximum voltage of 15v similar to an AGM written on the case. Its still brand new and I wanted to get a second one to wire in series but found out that they are not selling this product anymore. I wonder if I can get away with a 100ah AGM battery as the second unit in series. Also wondering if this battery is actually a gel cell if it has a maximum voltage of 15v. Thanks The battery is an eco-worthy VT12100 (green)

By: brian Ap

brian Ap — Thu, 07 May 2020 15:12:03 -0700

I use two lead acid batteries of field charging of hobby batteries. I bought a min kota digital precision dual bank charger to charge them. This charger uses what they call a "mild equalization phase" in the bulk charge cycle. I have come back to find the charger stuck in this phase for over 24 hours. Basically it can never get past this part and there is no fault timer to kick it out of this phase. I noticed that the batteries were boiling in this phase so I stuck a voltmeter on to see what it is doing. What they call " mild equalization" is just going up to 14.7 volts for the bulk phase. The charger is obviously looking for something to get past this phase. I can only guess that it wants to see some higher voltage to move on to the float charge. I was very annoyed that it would just go ahead and boil off most of the water with no signs of stopping. When I called tech support they said that I must just have worn out batteries since they don't have a problem with this line of charger. Are my batteries to blame or is the charger wearing them out by bulk charging at 14.7 V? They were 4 yrs old at the time and could indeed be "old".

By: Jack Martin

Jack Martin — Wed, 25 Mar 2020 22:29:38 -0700

What minimum voltage is acceptable for a 12V AGM (and other lead-acid) batteries upon receiving after shipment? The issue came up when I received a "new" AGM battery that arrived at X volts, and it seemed too low for a proper storage voltage, suggesting the battery may have arrived already a bit damaged.

By: Michael Trivette

Michael Trivette — Sat, 21 Mar 2020 17:16:46 -0700

I have a Kangaroo golf cart and it recommends a 12v Deep Cycle Gel with a minimum 31ah. What battery and charger do you recommend. The current one does not hold a charge for an entire 18 holes of golf. Thank you.

By: DennisoxYpe

DennisoxYpe — Sat, 15 Feb 2020 08:55:18 -0800

I simply wish to say I am newbie to blog and actually relished you're site . Most likely I'm want to bookmark your website. You certainly come with great posts. Thanks a lot for exposing your blog website.

By: CraigDiunk

CraigDiunk — Fri, 26 Jul 2019 13:29:17 -0700

Thanks pertaining to delivering this manner of terrific posting.

By: C Joseph

C Joseph — Sun, 30 Dec 2018 05:09:34 -0800

This article was outstanding the best I've ever read regarding everything you want to know about the various types of batteries, functions, etc. Thank you. Good job!

By: JaimeOxync

JaimeOxync — Wed, 18 Jan 2017 08:28:09 -0800

Good post! I read your blog often and you always post excellent content. I posted this article on Facebook and my followers like it. Thanks for writing this!

By: Jerry

Jerry — Sun, 15 Jan 2017 16:49:33 -0800

Hello,
I have a Ford Transit with a single battery system. I also have a 1000 Watt inverter that I use to keep my phone and laptop charged. I have drained the battery to the point it will not start the Transit so I am trying to add additional power to keep from drawing the battery down for a longer period of time. After reading your article, it sounds like I should avoid drawing the vehicle battery down too low. Would you recommend dual batteries, a deep cycle battery, or…? I would greatly appreciate any ideas. Thank you!

By: nate

nate — Fri, 24 Jun 2016 18:51:46 -0700

What is your advice on the best battery for a backup sump pump application?
From 0 to 2 times per year our AC power goes out when it is raining.
Perhaps once every 5 years it goes out when Niagara Falls is flowing into our sump pit.
When this occurs is it profoundly essential the backup system work.
Most backup sump systems appear to be sold with 12V maintenance free deep cycle 75 or 100 AH AGM batteries.
Does this seem like the best choice?
Also, the systems are sold with controllers that charge the batteries occasionally. I assume this is important to obtain maximum battery life. Any advice here on ways to ensure periodic charging is occurring?
Finally, any other overall advice?
thanks much
nate

By: mohamed omer

mohamed omer — Wed, 22 Jun 2016 00:48:45 -0700

This article is very helpful for me. But i have one more qn to ask. I bought a new 12v 200Ah battery.but there is no electrolyte.just empty. I poured distilled water and made to charge.after two days the plates getting coated with some white sludge.so what shud i do now.help me please.

By: Kwaku

Kwaku — Mon, 20 Jun 2016 09:07:42 -0700

How can one determine the number of plates in a battery by the batteries amp-hr? Is there a formulae to calculate the number of plates in a battery? Thanks

By: dilawar

dilawar — Sun, 12 Jun 2016 01:13:18 -0700

Sir i have a sunlight dry battry of 2volt 300amp, it is dead how can i recharg again.

By: Jason M.

Jason M. — Sat, 28 May 2016 12:04:59 -0700

Excellent resource. Great writeup. Thanks for sharing your knowledge with the world.

By: kevin

kevin — Sat, 07 May 2016 09:21:54 -0700

I am installing a 36 volt trolling motor and it calls for 6 gage wire. The boat had a smaller trolling motor installed on it previously and it had 2 , 10 gage wires together for the positive and 2 , 10 gage wires together for the negative . Will 2 10’s be sufficient to carry the amp load of a 6 gage or do I have to replace the 4 10’s with 2 , 6’s . Total lengths is 20 feet , but that should only affect voltage drop

By: derek

derek — Mon, 25 Apr 2016 17:16:36 -0700

Hi
I have a 100ah agm battery in my caravan which has buckled and wont hold a charge.
I am about to buy a new agm battery but hope you can advise me on the following.
When I head off on a trip I have the battery fully charged. I have an Anderson plug charging the battery whise we are driving, the question is, can a fully charged agm battery be damaged by overcharging by the charge it receives from the car while I am driving.
Regards

By: Dave brennan

Dave brennan — Fri, 18 Mar 2016 16:50:42 -0700

I built a paddlewheel for my pontoon boat using motors from a power wheelchair. I used the original batteries from the chair.2×12=24v.will I burn out the motors by changing to full size batteries or is 24 volts 24volts ?

By: Dean

Dean — Thu, 20 Nov 2014 11:09:55 -0800

Im a designer/installer and have read literally hundreds of guides and tutorials over the years and none are a patch on this – hats off, you’re brilliant – and crazy helpful to have provided answers to every question posted here individually, for free, despite you having already answered 99% of them in your other excellent articles!

People, don’t be lazy, sure this guy has a life so read ALL the FREE guides provided for you here before asking. Big respects

By: Mike Coshan

Mike Coshan — Wed, 19 Nov 2014 02:16:33 -0800

Fantastic article though I admit even the laymans terms seems to go over my head. I live in the UK and have a QUICKIE Jive Midwheel drive wheelchair made by Sunrise Medical which uses 2 × 12volt 70 amp sonneschein GEL Batteries I Have a 8amp Gel battery charger but in the 27 months I have owned the chair I’ve had to have 4 sets of replacement batteries as they fail after 6 months apparently ( according to the manufacturer) because of a faulty Cell. I have followed the manufacturers guidelines with charging the battery, which states as soon as you’ve finished using the chair put it on charge. . Though I often wait about 5 hours to put the chair on charge. I do this and then leave it. So the chair gets between 13 & 18 hours charge even if I have done only 5 miles, which is my about my average daily use. Should I put the chair on charge straight away the leave it alone even If I need it? I have my manual wheelchair to get about in inside my house. Any help to prolong the battery life is greatly appreciated. I have repeatedly asked both Sunrise medical & sonneschein for help over the past 2 years with n how to alleviate this problem but have had no reply.

By: Tech

Tech — Tue, 18 Nov 2014 11:30:15 -0800

The rating reflects how many amps you can pull from that battery over a specific period of time. In general the ratings goes down the quicker you pull a load out of a battery, so a 200AH 10 Hr rated battery will have a higher capacity than a 200AH 20 Hr rated battery.

By: kanzi

kanzi — Sat, 08 Nov 2014 09:00:14 -0800

I am in the process of upgrading my solar electricity in my house and need information regarding what electrical appliances 8 AGM batteries will be able to power. I already have a solar panel array in place that is powering a solar water pump very effectively. I suppose I need to tell you the amount of watts the panel produces but do not have that info. at this time. Is it likely that I can replace my propane frig. with an electric refrigerator, run power tools without the generator on, etc.?

Thank you!

Sandra

By: DaveT

DaveT — Sat, 18 Oct 2014 10:18:10 -0700

Great article. However, it seems that no matter how many articles I read on batteries, I can’t seem to grasp a full understanding of how it all works. And I say that because 6 years ago I purchased a highly modified EZ-GO golf cart that I use to get around the woods of southwestern Pa. year round. Our temps run in the high 80’s in the summer to the mid teens in the winter, and at times lower. I have a 48-volt system using 8 six volt T-105’s and a smart charger for the cart, and for my headlights and winch a separate vehicle 12-volt battery. Now, I’ve read that I should not discharge my flooded T-105’s below 50%, but in all honesty, that is at times impossible to do. The woods are not that short in places, and at times…well mud is mud and you can’t predict it. However, I always check my water levels…they seem to remain a constant…and I always clean my terminals monthly, even if they don’t seem to need it. Your suggestions of using grease is great and I will do that on my next cleaning session. Now, I have installed a new Warn winch and I winch my cart on and off my truck. I currently have one 12-V auto battery in the cart, but I am concerned that I may be “out there” and the 12-V simply run out of charge. So, what I have been thinking of is replacing the one 12-V with two 12-volts and wiring them to still have a 12-volt output, but have a longer output “time” if you understand what I’m saying. I have enough room under the cart seat for the average width of a car battery, and about 24” in length. What type of batteries would you suggest would work the best in my situation?

By: earthrealm

earthrealm — Thu, 16 Oct 2014 02:46:47 -0700

please, am a little confused. whats the difference between a 200ah 20hr rated battery and a 200ah 10hr rated battery. am trying to buy a deep cycle battery and i see 10hr on one and 20hr on the other. which one is better?

By: Stella

Stella — Tue, 14 Oct 2014 08:09:31 -0700

Thank you so much for writing this. I am certainly going to give to my husband to read and for reference. I just purchased a yamaha 36v golf cart that needs new batteries. There are 6 each, 6 volts batteries, which would you suggest?

thank you !

By: Darren

Darren — Fri, 03 Oct 2014 19:56:38 -0700

Hi, I have been getting a headache with all the conflicting advice on my current and planned dual battery setup. I have a 105 Landcruiser with 4.2 diesel and standard 110 amp alternator. I have a dual battery system with a Delkor 27HR-70 Calcium and a brand new Optima Blue Top D27M AGM (replaced the other Delkor which died) as the secondary battery for running utilities (fridge etc). They are parallel connected through a RedArc 100 amp isolator. I also have a RedArc 120W portable solar setup to assist with powering for extended camping etc.

Firstly, is this current setup likely to damage Optima through lack of charging output. And if so would an in car BC/DC charger resolve the issue.

Secondly, as I am not sure of the age / condition of the Delkor I am thinking of replacing it with a new Optima Yellow Top D27F. Would this make my current setup sufficient? Or is the standard 110 amp alternator still not up to fully charging the AGM’s?

Would really appreciate some feedback and guidance

Cheers

We would require more information about your situation. Please contact one of our techs at tech@batterystuff.com.

By: Suz

Suz — Sat, 20 Sep 2014 04:12:55 -0700

Wow…thankyou for existing. We are beginning to get a solar set up organised for free camping and I have a plethora of questions that hopefully you can answer for me. We intend to run a 12v52 litre fridge and strips of led lights. What do I need to know about these applicances when planning the battery set up. We are looking at a 12v 260 AH AGM battery using a 140W solar panel to charge. Would one battery be enough or should we look at two – the fridge needs to run most of the time but the led lights would be just at night. If we did get two what is the difference between wiring in series and in parallel ….is one way better than the other?? And I need reminding … In paralel is it positive to posiive and neg to neg.. Thank you so much for your time and expertise……cheers Suz from Oz

By: WILLIE

WILLIE — Tue, 16 Sep 2014 14:22:18 -0700

A BMW 128i w/AGM BATTERY—-CAN IT BE REPLACED W A QUALITY WET CELL BATTERY?

THANKS—

By: Kyla

Kyla — Fri, 05 Sep 2014 15:17:00 -0700

Great article, easy to understand and informative. I have a few questions about my RV battery cables. I was about to replace the 2 12v marine batteries on my RV with 2 6v deep cycles, when I realized the cable situation seems strange and possibly scary.

- The ends of the cables, for about a foot before the terminal connectors, are all taped up and homemade. Should I be concerned about that? – How do I know if they’re an appropriate size for the battery size? – There is a thin black ground wire coming from the taped up part of the + cable, which is bolted to the trailer frame. Why would the + cable be grounded? Isn’t that what the – cable is for?!

The 2 cables that were used to connect the 12v batteries in parallel are also of this taped-up homemade variety. I was going to use one of them to connect the 6v in series, but now am unsure whether I should use ANY of these cables at all. Wiring in new cables seems really daunting because I can’t see an obvious way to access where they run up into the bottom of the trailer. But I don’t want to be unsafe, so…

Thanks in advance :)

By: Joel

Joel — Thu, 04 Sep 2014 10:31:16 -0700

Hi, I bought a sailboat with 2 batteries and a selector which reads off/1/both/2
My question is about what you say about batteries being the same size, rating and type. Of the 2 that came with the boat, #1 is a reg. acid starting battery and #2 is a deep cycle used as a house battery. Is that bad? should I avoid the “both” position of the selector?

By: Maurice

Maurice — Sat, 23 Aug 2014 18:45:10 -0700

If AGM batteries aren’t damaged by a car’s alternator charger why do they need a special charger?

By: T-Man

T-Man — Sat, 16 Aug 2014 11:39:56 -0700

Thank you for some great info. We have a travel trailer that we have parked at a camp area on the back the farm. It hasn’t moved since we bought it 5 years ago. We charge the battery with a Honda 3000 generator. After many years of frustration using a flood cell deep cycle battery we just installed a AGM battery. (I believe we brought the charge down on the batteries too far, too often). Anyway we just bought the AGM battery because we understand it will charge much quicker than a flood cell. My question is using this type generator on a trailer, will that work for a AGM or should we do anything different for charging?
Thanks again.

By: Laura Hargis

Laura Hargis — Wed, 23 Jul 2014 12:35:36 -0700

We have a John Deer Gator (riding toy)for our Granddaughter. The connection for the battery has corroded down inside. Is there a safe way to clean it out? It is a very tight area.

By: Md. Saiful Haque Khan

Md. Saiful Haque Khan — Fri, 18 Jul 2014 13:06:49 -0700

I have two 12v 100AH battery it is connected with IPS recently I see the battery is very HOT & IPS Full Charge indicator not showing full charge. I check Battery Water Level ok. Then I disconnect all battery from IPS 2 days take time to cool the battery & after battery fully cold I connect it to IPS but again the battery is very HOT. What is just happening Can you tell me please.
My battery Name Lucas AP 100 12V 100AH 21 Plate made by Rahimafrooz Bangladesh. Please give me the repply. Thanks
Saiful Haque Khan
Bangladesh
saiful6848@gmail.com
+8801716579824

We would require more information about your situation. Please contact one of our techs at tech@batterystuff.com

By: GarthJ

GarthJ — Tue, 15 Jul 2014 09:58:31 -0700

I have a boat with a normal marine 12v lead acid battery I would also like to add a second battery to provide for lets say a 12v access port for accessories. Unfortunately I have limited space for a second full sized battery. Could I use a smaller lets say ATV type twelve volt battery connected through a dual battery charger relay isolator so that both would charge when the motor is running but both would not drain when the motor is not running.

We would require more information about your situation. Please contact one of our techs at tech@batterystuff.com.

By: ArieS

ArieS — Tue, 08 Jul 2014 14:50:25 -0700

I have a few questions on battery reconditioning, based on reading of various How To and DIY sites, and hope that you are able to help: 1 – The powder that everyone seems to suggest is Epsom salts, is that correct? 2 – Is there a specific type of these Epsom salts that is appropriate? 3- What are the mixing specs for the solution? Thanks a lot!

We would require more information about your situation. Please contact one of our techs at tech@batterystuff.com.

By: Tracy

Tracy — Thu, 26 Jun 2014 12:50:14 -0700

I have installed a few advanced GPS devices on a fleet of vehicles. The manufactures paperwork says they should be wired into an output capable of at least 13 volts. I have not had any problems with the devices on vehicles with a normal 12 volt car battery and wonder if there would be any possible problems if I wanted to install them on a recreational vehicle like a Polaris ATV/Quad or a Side X Side with a 12 volt battery?

By: Zareef

Zareef — Sat, 14 Jun 2014 11:37:29 -0700

I had solar system, Know I want to add new set of batteries with old one for charging purpose, both pared as 24V sets. 24V old set and 24v new set. is this work or any problem, i will face during charging for solar panels.
or should i charge separtly and use dual purpose. Once charge new and than Old.

In house for electric city,Should i combine both sets, or I use old to discharge than switch to new for use.

By: Randy

Randy — Wed, 21 May 2014 09:58:56 -0700

We have a few 10 tonne dump trailers that are towed behind a few chev 2500 3/4 ton trucks (1 alternator)1 battery. Also towed by 2 ford 1 tons which have dual batteries in them.
We are using deep cell wet batteries 175AH (D27’s) one battery in each trailer. The batteries in the trailers only get a 1/2-1 hour charge from the 7 way trailer plug when they are ran to site and dumped. I don’t have the amp draw of the “Dyna-Pack) electric/hydraulic motor/pump unit yet. It takes 15-30 seconds to fully dump the trailer. The batteries don't seem to last too long to these guys. The charge from the tow vehicle may be to low as the voltage drop in the 12 or 14 ga. wire used in the typical trailer tow package. I was thinking about wiring in #4 ga. from the font to the rear trailer with a battery isolator so the trailer battery could receive a better charge rate., specially if being dumped every hour or two and only getting 1/2 or little more charge in between. Is it worth it $150 + isolator. I can install and get reasonable pricing on wire & terminals etc. Also what is the best battery to use as the trucks have different batteries in each of them?? Good site for info I must add.

By: Jim Bigger

Jim Bigger — Mon, 12 May 2014 02:49:19 -0700

But why are there no tech replies in 2014?

By: Frank Tucker

Frank Tucker — Fri, 02 May 2014 23:36:28 -0700

I have n ABM 12volts, 120AH battery and a Wet Cell 12volts ,120AH battery can I connect both of them to my solar system in parallel

By: Sam

Sam — Tue, 29 Apr 2014 05:58:21 -0700

With a BS in Chemical Technology and eperience with batteries, I congratulate you for this article where expertise and general public understanding are mixed in a state of the art level. Talking for shalow cycle batteries where Ah has no sense because CCA matters people has to be aware that this battery has to be fully charged, and if discharges only 20% i.e below 12.6 V affects the life of the car battery. The status of battery has to be checked every weak, while you check the cold inflation pressure of the tire. To have a optimal inflated tire, means an optimal tire foot print i.e an optimal tire grip. So at this time check the battery voltage in your car parked overnight, start engine check again and you’l get 13.5 to 14.5 i.e. this is the status of alternator and voltage regulator in your car. If not using a vehicle use a battery tender that start charging at 12.6 V and stops at 14.2 – 14.5 V. Not hapy with comercial battery tenders, I made my own using a NE555 timer as precission comparator an more component. I can adjust ON at 12.6 – 12.7V and of at 14.2 to 14.5 volts according to the status (age ) of the battery. Increasing the battery voltage above 13.2 V, starts equilizing process. The weak cealls continue to charge and the strong start boiling. I do this proces at 250mA untill battery saturated, and after turns OFf to let battery to relax. I never buy a maintenance free battery, because I must check the electrolyte, level, top with H2O, and if necessary check the density.

By: Marie

Marie — Sat, 05 Apr 2014 20:50:29 -0700

Sir Good day! i need with my newly bought gel battery, i dont know if i have to add sulfuric acid… i used it with my u.p.s. and it cant five any power to my computer when i unplug the power cable of the u.p.s.when i read the power rating 12.5V i dont know the ampere since i dont have amp meter. but in the battery it says 7Ah/10H. i thought it is better than my old VRLA with 12V 4.5Ah rating

By: Dave M

Dave M — Sat, 05 Apr 2014 19:34:25 -0700

Can you use a AGM battery by laying it on it’s side or must it be in the upright position? If so, does it make any difference what side it lies on (battery posts toward the top vs toward the bottom)

By: Anders D

Anders D — Tue, 18 Mar 2014 09:02:39 -0700

Best written, most through article I have read regarding batteries, thank you!

I have a BMW with AGM battery that was just replaced. I purchased a CTEK multi us 4.3 smart charger to lengthen the life of this new battery. I attempted to charge 3 days after installation, but became concerned as the charger was hot to the touch after 2 hours and still in the bulk charging state. Should I be concerned by the heat? There was no indication of anything awry other than the charger itself being hot.

Interestingly, the old battery never remained in the bulk charging state this long and I never experienced the charger ever being warm.

By: Athar

Athar — Mon, 17 Mar 2014 05:15:58 -0700

During periodic check when I observe that water level is low, I add distilled water to cells of lead acid battery. After a short time the fluid starts oozing out from the caps. It continues for about 12 -15 hours. What is the cause of this problem and how it can be rectified?

By: Feterom adolfo

Feterom adolfo — Mon, 10 Mar 2014 03:19:20 -0700

What are the electrodes and the electrolyte of an AGM battery????

By: Harold

Harold — Sun, 19 Jan 2014 06:03:31 -0800

Thanks for a very informative article. I own an older Honda Goldwing with lots of electrical gizmos. I have replaced the battery twice in last year. My dealer replaced the last under warranty about three months ago. The new battery worked fine when I was driving the bike frequently. But after letting the bike set for about two weeks I now have another dead battery. I hooked up my trickle charger, it only has a light that tells me it is charging, I left in on for about a week it did not recharge. I then hooked up my battery charger, it tells me it the battery is fully charged at 6 volts. Does this mean I have three bad cells? This is the second time this has happened, the first new battery lasted about six months this one about three. Do you think I got bad batteries. One I think maybe, but two in a row.

By: Larry

Larry — Mon, 02 Dec 2013 17:31:01 -0800

What a well written article. Thank you!

My interest in the topic comes from wanting to maintain our trailer’s 12v AGM battery over the winter. We brought it home and put it in the basement workshop, but I discovered tonight that it was down to 10 volts.

I’d like to put it in the cold room where there’s an unused plug but was worried about the “well ventilated area” instructions. The article says AGM batteries are the safest type, so would it be safe to charge it in the cold room? (10 × 4 × 7 feet, with top and bottom 4” pipe vents)

By: John

John — Sun, 01 Sep 2013 15:04:43 -0700

Brilliant article. Has really explained the internal working of various makes of batteries, better than anything I have come across here in the U.K.

By: Pulkit

Pulkit — Tue, 25 Jun 2013 22:39:14 -0700

Hi.
I have 2 12 Volt batteries and want to use them both/ But i still want to use them for 12 volts. I just want extra backup.
Please reply me anyone ASAP.

By: Sandie

Sandie — Thu, 09 May 2013 16:35:28 -0700

I am battery deficient. I am charging a battery on trickle charge, I know that much, but how do I know what the red and black bits on the charger mean? And how long til it charges? My hubby used to do all this but alas he is no longer here.
Thanks for input

By: donna

donna — Tue, 30 Apr 2013 05:55:55 -0700

I need a battery for a lighting setup for artfair booth (outdoors).
I want to use 6 LED lights (14-watt Par30 bulb 3500K).
also use of a fan for cooling the booth.
which type of battery do you recommend.

By: David

David — Fri, 12 Apr 2013 16:36:33 -0700

Is it possible for a AGM battery to test 100% on a load test and still be bad? My battery shows 12.8v unconnected. In the motorcycle it shows 12.6v and with the key on it drops to 12.1 and won\‘t start the bike.

By: John

John — Tue, 19 Mar 2013 09:50:34 -0700

I have a 12v 100 amp hour wet cell battery at work. It was taken out in the fall and put on a smart charger. Now I was going to reinstall it back into our equipment. I noticed that the end with the negative post is swollen. With a load test it passes at 9.5v‘s. no other physical damage is found on the case. Could the one cell have pressured up and not vented?

By: Sean

Sean — Sun, 17 Mar 2013 00:16:01 -0700

Question, i have access to some lead acid batteries with much more life left in them…..more than i need at any one time. I want to put some in extremely long storage (5to10) yrs) Can i remove the electrolyte, flush then store? I read somewhere after flush to refill with ph neutral water and storing worked well. Another that after flushing used inert gas argon and sealed battery vents. Not concerned with losing a little capacity as these are very robust batterys. what would you recommend. I would charge these fully then remove electrlolyte and store it properly until redeployment.

By: tim

tim — Sat, 16 Mar 2013 06:54:02 -0700

Great Article. If I have a 80 Amp Hour battery and use a winch that is drawing 435 Amps under load with a 90 Amp alternator on the vehicle, how many minutes can I winch before I fully drain the battery or cause the vehicle to turn off? What formula are you using?

By: Donny

Donny — Mon, 04 Mar 2013 13:44:18 -0800

Do you recommend a 2 battery solution for a boat? 1 for starting and 1 for deep cycle? Or would a dual purpose battery be sufficient? The engine is a 90 hp outboard.

By: Jerry Anderson

Jerry Anderson — Sun, 17 Feb 2013 09:50:08 -0800

I have a Yamaha golf cart I purchased 4 yrs ago. Last winter I parked the cart in my heated garage and did not recharge the batteries during the 3 1/2 month period. By spring the batteries were so discharged thatmy cart charger would not work. I used a car battery charger to charge the 4 12V batteries separately. I limped through last summer having to charge to cart every 18 holes. I haave recently read about de sulfating the batteris. I was thinking about trying this before I spring for new batteries. Can you recommend a product to do this and if I can use the cart charger when doing this or would I have to charge the batteries individually. Thanks for the great article.

By: Reg Rayner

Reg Rayner — Tue, 12 Feb 2013 20:59:00 -0800

Sir, Thanks for the article. I Have a yacht with 4 Trojan T105‘s(6v – 2 in series- paralleled X 2) as one bank and a truck and tractor battery as the other bank. These are constantly charged by both solar panel and wind generator ( through a regulator) and also charged when the motor is running by alternator.
My question;- Can I replace these wet cells with AGM batteries without changing any charging facilities? and if this is OK, do I replace them all with dual purpose AGM‘s or do I have 2 different banks, 1 starting , 1 deep cycle. I have a manual(idiot) switch, for selecting each battery bank or both. My motor is a Ford Lees 85 HP deisel. Thanks in advance.

By: Nicki

Nicki — Sat, 02 Feb 2013 19:17:04 -0800

Hi,
my husbands 650cc motorcycle wasn‘t turning over so we figured it was the 12v battery. In order the check that it wasn‘t anything else we hooked up my new smaller scooter 12v battery to his bike and got it running. Now the scooter battery won‘t even turn the lights on the scooter even though the voltage meter says its fully charged. Could we have damaged the battery by using it in a different machine? The bikes take different size batteries with different amps but both 12 volts.

thanks.

By: Mizanur Rahaman

Mizanur Rahaman — Fri, 25 Jan 2013 11:17:19 -0800

Sir, I want to know a matter. When a 12V, 7.2AH rating battery is fully charged, is there any current flow to the battery where the charger is still plug in? and what is the actual voltage when the battery is fully charged? Please ans. to me.
Thanks in advance.

By: Ms. Safety

Ms. Safety — Fri, 18 Jan 2013 12:05:57 -0800

THANK YOU!!!! The information on this page was GREAT!!! It is now my “Go-To” reference for batteries!!!!

By: Silas

Silas — Thu, 17 Jan 2013 08:42:58 -0800

Sir I will be very thankful if you guide me to build a charger of a 4 volt Li ion battery(which I have dismantled from my old laptop battery)……Thank You.

By: Adda Lamon

Adda Lamon — Wed, 16 Jan 2013 08:41:32 -0800

I found the article SUPER helpful, because the guys at the auto parts store we talked with did a few confusing things. One guy called a battery looking like a 6-pack of soda cans a gel battery, where as the guy he called in for more info called it AGM, which it probably actually is. However, the guy who actually did know it was an AGM battery told us specifically that it wouldn‘t have any problems if it was completely discharged…which sounded quite attractive. We‘re still planning on purchasing the AGM batteries, but if I hadn‘t found the web page and wised up on the great info and tips you folks provided, we might have blithely followed his information and totally killed our battery (sucksville!). Thanks for a great website!!!!!!!!

By: Mike Smith

Mike Smith — Sat, 12 Jan 2013 16:48:13 -0800

Very Informative! (I assume 1 to be the highest rating). I have an \‘85 Ford class C motorhome with 2-12v batteries. Not sure if they\‘re connected in series or parallel. It has a single alternator and a separate voltage regulator. With the engine running, one battery reads 12.4v, the other reads 16v. I assume this means the alternator is trying to charge this battery more? I first thought the regulator was bad & replaced it. At that time, one battery was reading 16.4v & the other 16.2. I discovered I had bought the wrong regulator, so I bought a second one. It read 16v and 17v. I put the original regulator back in, leading to my assumption that one battery won\‘t hold a charge and the alternator/regulator is trying \“harder\” to charge it. The batteries were in it when I bought it, but they\‘re different brands & I have no way of telling when either was purchased. Would my assumption be correct, and should I replace the battery with the higher voltage reading (or both)? What started this was when I bought the rv, before driving home I turned on the headlights and one went out immediately. I turned them off & the seller turned them back on & the second headlight went out. I left it for him to fix. He replaced both headlights. The first time I used them the new ones went out together. I switched to high beam & after about 10 seconds they both went out. I knew something was wrong & suspected the regulator first.

By: Garry Mcdonald

Garry Mcdonald — Sun, 06 Jan 2013 14:43:27 -0800

RE; Can anyone please help? Scooter battery problem, will not take a charge.
It appears that there may not be anything wrong with my batteries. I was told that the batteries must be charged every month or two or sulfation would set in. But the batteries not excepting a charge after 4 months was concerning. With no answers I decided to drain the batteries of two scooters by running the motors with the throttle on full and turning the lights on. However after 5 hours of constant running the scooters meters were still showing full and the volts where at 48.7 and my volt meter was showing 48.6 volts. After 5 hour only dropped 2 volts while protection shutoff is 42 volt. The next day I charged the batteries and yes they took a good charge, 7 hours and still taking a charge when I left for the day (I have them on a 12 hour timer). These Chaowei deep cycle gel batteries must be very good with little self discharge to not except a charge for 4 months.

By: Louw Penni ng

Louw Penni ng — Sat, 05 Jan 2013 13:18:35 -0800

Hi,
Very informative article, thank you. I have a problem with my camper van, 24 volt system for the truck, 25 amp alternator, fridge in the house on the truck that draws current from the 2 × 12 volt in series truck batteries. When ignition is off, the fridge stop drawing current. However, the truck batteries constantly run flat during driving, all well while I drive (diesel truck), but next morning the truck batteries are almost flat. The camper van house has it\‘s own 12 volt battery, charged from solar, it performs OK. Currently the 12 volt fridge element draws amps from the second 12 volt truck battery, this implies that the fridge uses the power from the battery, not directly from the alternator. Is it possible that the power outflow from the battery is more than the charge inflow into the battery?. How many Amps can a battery continuously take while charging?. I now think I must tap the 24 volt directly from the alternator, then put it through a rectifier to get 12 volt, and then onwards to the fridge. This will leave the truck batteries free to charge at will without being drained by the fridge. If the truck batteries can only charge at say 6 amps, while the fridge draws 10 amps, the current set up will always discharge and leave me with flat batteries. Am I correct in my reasoning?. Please advise asap, Many thanks, Louw

By: ed

ed — Wed, 26 Dec 2012 14:29:52 -0800

i have 3 sb 12100-s 12 volt 10 amp batteries for my bike which were stolen how do i wire the new ones?

By: ed

ed — Wed, 26 Dec 2012 14:22:12 -0800

i have 4 batteries ps 1272 fs 12 volt 7.2 amp batteries were stolen how can i wire theser my bike?

By: mike

mike — Mon, 17 Dec 2012 19:34:32 -0800

I use 4 – 12 volt dcm0035 interstate batteries hooked up to 48 volt configuration to power my pedicab. I have 2 sets-8 batteries total. They have had 11 months of being drained to approx 12 volts on the meter 3+ times a week. I use 2 noco gen 4 chargers. Mostly in the 10 amp mode….but sometimes doubled up on one battery set. Weather conditions from 35 – 110 F. How can I determine how much life is left? Besides the obvious based on how long they run before being drained. It seems they are at about 50% of new. Also…does my charger do a real 100% charge

By: andy

andy — Sun, 16 Dec 2012 14:09:14 -0800

I purchased a used boat in 2009, it has 2 identical West Marine starter batteries 650 CCA with a Perko 3 way switch, 1, 2 both or off). I\‘ve never charged these batteries other than while running my boat, which is probably less than 50 hours per year. The engine is a 175HP Suzuki, with a 44 amp alternator. I feel like I\‘m running on borrowed time and want to replace these batteries with AGMs. Should I go with 2 starter type batteries or 1 starter and 1 house? While boat is running is the alt charging both battery at the same time or does it follow the path of the Perko switch? Thanks, great site.

By: nand

nand — Tue, 04 Dec 2012 01:36:41 -0800

Is it possible a Low maintanance Lead Acid can charge and discharge Simultanously ?

By: Murugan

Murugan — Tue, 20 Nov 2012 01:51:22 -0800

(continued…)
I am using a 17 inch CRT monitor which consumes 80W power. Here in India we use 220V Ac for our appliances.

By: Murugan

Murugan — Mon, 19 Nov 2012 23:09:54 -0800

i bought a 12Volt battery 22months back with inverter for my desktop computer only. It reads GT-2100 C20 210AH. It\‘s a lead acid battery. The dealer told me that i can use it for 10 and half hours for to power my computer only. from internet i came to know that one should not fully discharge a battery. i till date only once i used it up to 9 1/2 hours. never seen \‘battery low\’ blinking any time till date. I always carefully kept the water level full by regularly checking the level indicators. On an average i use the battery up to 7 to 9 hrs these days because of big power cuts here and see it charged fully immediately when power comes. One problem is that if i use the battery for 9 hours then there has to be continuous power supply for at least up to 8 hours(+minutes) to get fully recharged. but here they are supplying power only on alternate hours. i.e, one hour power supply – one hour power cut – one hour power supply. and that too during the night only. during day time only for four hours power in given- morning 8to10 and evening 4to6. rest all day power cut. only in the past 3 months power supply became like this. i have been forced to use my battery very carefully and judiciously. My questions is will it affect my battery life by leaving it to be charged in alternate hours?.(i don\‘t use it during night while being charged). i am really worried. we have abundant sunshine here. so i am willing to explore the possibilities to charge it using a solar panel. i want to know the maximum wattage or voltage should i supply to charge it in the minimum amount of time possible. tell me this much wattage up to this much hour. here we have 10~ hours of bright sunshine. please help.

By: Fawad

Fawad — Mon, 19 Nov 2012 00:09:30 -0800

My AGM 100amps battery for UPS is acting strange it gains full charge with 30-50 mins while it also discharges with 30-40 mins, my UPS is charging the battery on 10-12 amps. Any Help

By: Greg

Greg — Sun, 28 Oct 2012 18:22:53 -0700

”… An amp hour (AH) is a rating usually found on deep cycle batteries. The standard rating is an Amp rating taken for 20 Hours. What this means, say for a 100 AH rated battery is this: Draw from the battery for 20 hours and it will provide a total of 100 amps …”

Should say …
”… and it will provide a total of 100 amp-hours …”

By: david cuneo

david cuneo — Fri, 26 Oct 2012 00:36:12 -0700

Thank you for your article, I have a question. I bought a 2 month old (STICKER ON IT) battery from junkyard, outside cell was punctured in a crash, looked inside all electrolyte was gone from the one cell. I repaired the plastic casing,it could now hold liquid safely. Could i add electrolite from an old battery or would that have too many sulfites , it would be better to get a motorcycles worth at autozone? I am going to turn in my old battery anyway as it is a core charge… What do you think?

By: Wilfred Kube

Wilfred Kube — Mon, 22 Oct 2012 16:35:24 -0700

I have a Toyota Coaster bus which is fitted out as a motor-home. The vehicle was manufactured with a 24 volt electrical system, which uses two batteries in series, of 12 volts each. I have outlined a description of the auxiliary electrical system below, but my basic question is, how can I know how depleted my auxiliary batteries are at the end of a day in which the refrigerator has been working for a long time?
I think the basic rule is that the batteries should not be discharged below 50% of their capacity, but what reliable method can I use to determine when they have reached this point? There are two auxiliary 12 volt batteries in series, each 120 amp-hour, to provide power for the “house system” – namely refrigerator, lights, water-pump, and various 12 volt power outlets. The refrigerator is the major user of battery power, because it is a compressor fridge which uses the equivalent of 12 volts 8amps (i.e.96 watts) while it is running, and it runs for approximately 8 to 12 hours in each 24 hour period depending on how hot the weather is. The auxiliary batteries are charged by two solar panels of 80 watts each, and receive additional charging from the vehicle alternator when the engine is running. There is a battery isolator which automatically disconnects the auxiliary batteries from the vehicle electrical system when the engine is not running. The voltage regulator for the solar panel charging system provides a constant display for the auxiliary system, including the auxiliary battery voltage. I have been in the habit of checking the voltage last thing at night, and first thing in the morning, to find how much power the fridge has taken from the batteries. If the night time voltage is below 24.8volts, then the morning reading is below 24.0 volts. The problem is that if we have not done much driving on a particular day, and the solar panels have not done much charging because of cloudy weather, the night-time voltage may only be 24.2 volts, and the morning voltage not much above 23 volts. If the battery is at 24.2 volts when the fridge is not running, then when the fridge starts running the voltage reading drops down to about 23.5 volts. And so my question remains, what is the lowest acceptable voltage for my auxiliary battery system, so that the batteries are not damaged by being discharged too much. Thank you for reading through a long and detailed letter, but I wanted to provide sufficient background information.

By: Peter

Peter — Sun, 14 Oct 2012 15:22:17 -0700

Thank you for your great work! I have learned a lot.
I have a Die Hard 1150: 20ah AGM power pack. As per your explanations, I leave it plugged in because it has an integrated smart charger that is supposed to provide a safe float charge to maintain the battery‘s health. I have two questions relative to this:

1. Is it normal that the battery is slightly warm to the touch when it is plugged, has reached 100% and is receiving a maintenance charge?

2. Are dangerous gases given off while the battery is plugged in and receiving a trickle charge? My battery is plugged in in the basement workshop in a fairly large house.

Thanks for any information you can provide and take care.

Peter

By: Matt

Matt — Tue, 09 Oct 2012 16:31:36 -0700

Great article. I learned more than I‘ve ever known about batteries, but I still don‘t know much.

I am wondering, I recently purchased a year round ice fishing house / camper. I‘m looking at batteries now and am leaning towards an AGM. Is that what you would recommend? Again, this battery will be used year round. Freezing cold when it sits for 4-5 days at a time without being used, then it will be used on the weekends when I go fishing. Then during the summer it will be used in the heat.

I‘ve also seen a couple mentions of solar chargers. I do have a generator that i plan to use to recharge the battery when necessary, but am wondering if it would make sense to leave a solar charger hooked up to the battery constantly. The location of the battery in the house would make it very simple to hook a solar charger up and have it mounted either directly in the window, or just outside attached to the side of the camper/fish house. Then even when in use, the battery would be charging, right?

Thanks in advance for any response.

By: Adam Johnson

Adam Johnson — Thu, 27 Sep 2012 07:00:09 -0700

Thank you for your opinion….I would like to use an electric golf cart for in-town transportation in a small town in the San Juan Mountains of Colorado, year around. I am a teacher and typically only drive it back and forth once or twice a day, about one mile each way. 1st question: It can be very cold here on winter mornings, (-20 degrees and more),but then warm-up to 30 degrees on the same day, is there a battery that can handle the temperature range, and still have a reasonable life length? 2nd question: I have a solar panel that I could place on the roof, get a charge controller, and have the batteries always trickle charging, how will that effect the battery life? I have a 36 volt charger that came with the cart. The cart is perhaps 20 years old. The batteries it came with were all exhausted, I took them to a recycler. I was thinking of spending the 150.00 each ( including core fee) for 6 batteries, and stop driving my gas vehicle. I\‘d appreciate some advice.

By: Ameya Pawar

Ameya Pawar — Wed, 26 Sep 2012 04:55:11 -0700

I want to increase the voltage of 2 batteries from 24V to 180V. Is it possible?

By: Selvan Albert

Selvan Albert — Wed, 19 Sep 2012 07:26:36 -0700

Hi all,

Current setup:
1) Two UPSs. Both are independent systems.
2) Both are identical; Manufacturer: Delta; Model:J-Series 7 KVA. Each capacity: 5000 Watt, 230 Volt AC.
3) Each has 20 numbers of 12 Volt 26 AH batteries connected in series for a 240 Volt DC, 26 AH battery bank.

Objective:
a)Design a battery bank in such a way that even if one battery fails, the bank would still be operational and keep the UPS running until the failed battery is replaced.
b)Try reconfiguring existing battery bank so that cost is minimized.

Proposed setup:
1)Instead of two identical but separate battery banks as configured now, reconfigure the 40 batteries in one battery bank.
2)Batteries will be connected in series and also in parallel as listed in the diagram.
3)Two batteries will be connected in parallel to form one 12 Volt 52 AH parallel battery bank pair. Twenty such pairs will be linked in series to form one 240 Volt DC 52 AH bank.
4)Connect both UPSs to this one battery bank.
5)The 230 Volt AC “Output” of the UPSs would remain independent as they are now.

Attached Diagram:
Both the current setup as well as the proposed setup are illustrated.
(No change in the independent “Outputs” of the two UPSs. The 230 Volt AC “Output” of the two UPSs would remain the same (as independent outputs) in the proposed setup as they are now in the existing setup.)

Advantages:
1)When any one battery fails, the entire bank would still be operational. (Hence, the UPSs will not fail.)
2)So long as “both” batteries connected in any parallel pair do not fail, the bank would still be operational.

Question:
1)Would the battery charging circuits in each UPS somehow interfere with each other?
2)Are there other issues and/or disadvantages in the proposed system that are overlooked?
When electrical power is On, would the battery charging systems in each UPS interfere with each other when charging the single battery bank? In other words, currently just as one UPS charges its own battery bank, would the two UPSs charge the single common battery bank without issues?

We would be very thankful to you if you can please give us your valuable feedback on our proposed battery bank set up.

Selvan Albert.

By: Mark

Mark — Mon, 17 Sep 2012 11:44:16 -0700

it helped me alot but google‘s better

By: austin

austin — Mon, 17 Sep 2012 11:41:47 -0700

this rlly helped me in my auto electrical class

By: Bo

Bo — Tue, 11 Sep 2012 13:53:34 -0700

Hi James, thank you for the information and excellent explanations! How can I figure out what type of battery in my car (2007 BMW X3)? The battery is a sealed maintenance free battery. It’s the original battery. The part number is S: 61 21 8 385 398, and the label says it’s 90 AH and 720 CCA, but no manufacture name on it though. I called couple of BMW dealers, but they didn’t know. Hopefully you can help me out. Thanks in advance!

By: Charles Wehland

Charles Wehland — Sat, 08 Sep 2012 13:34:37 -0700

I have an electric 2-wheel scooter that my wife uses. It has 3-batteries linked together. How do I hook-up the cables on my battery charger to charge this bank of 3-batteries?

By: Bob

Bob — Fri, 07 Sep 2012 23:38:49 -0700

When using a deep cycle battery in a Solar system, using DC 12 volt lights. Is there a way to automatically shut off the lights before it discharges the battery too far?

By: John Fetter

John Fetter — Thu, 06 Sep 2012 00:52:31 -0700

This is a philosophical comment. Lead-acid batteries suffer from self discharge. Batteries actually spend overwhelmingly most of the time not on charge but doing absolutely nothing at all. This is what causes sulfation. So what do the experts recommend battery users do? Treat the sulfation. A hundred year old cure! How about treating the battery with something that stops the self discharge?

By: Will Helbich

Will Helbich — Fri, 31 Aug 2012 15:38:11 -0700

I have new replacement 4 × 12v 18 ah deep cycle agm batteries wired in series for an e-bike, the 48 v charger charges the bank at around 54-55 v, Now,the original batteries performed the last 2 years as expected for 300- 400 cycles with good range , but these new replacement batteries are failing within weeks, less than 30% range than originals. When testing the charging voltage going to each individual battery in series , it varies from 14.1 V- 15.9 V from one battery to the next. and under a timed load test on each charged battery, they range from 2 min to 55 min before dropping below 11.5 /cell. Are the batteries poorly constructed or is it a charger issue? Thanks for any insight you can provide.

By: jeff

jeff — Mon, 27 Aug 2012 17:01:44 -0700

Hi, just got a new kirkland battery and it has the 6 cells under the cap. Not all of the cells have liquid in them to the top. is this normal for some cells to have more liquid than others, should they all be filled to the top? I could not see any fill lines as to where the level should be. thanks

By: Qusay

Qusay — Sun, 19 Aug 2012 18:52:44 -0700

hello i have 8 deep cycle battery 12v 200Ah connected series/parallel to supply a ups system and it charged by acostant charger 52.5 V 35A its working abot 18 month every day about 6hr on the UPS and now begin loose its capacity when i check the voltage for each battery while the charger working some of them give 13,4v and other 12.66 and 12.9 so it the sulfated or need for reacharging with a smart charger .

thanks

By: Max Williams

Max Williams — Thu, 16 Aug 2012 02:52:52 -0700

Hi
I have (8) x 6V x 125AH deep cycle batteries producing 24V in a series/parallel config
charged by a 250W x 24V solar panel,powering a 24V fridge/freezer 24/7 drawing 2A when running.
Am i correct in assuming my total stored AH capacity should be sufficient to run the fridge
with minimal sunlight for a few weeks.
Cheers
Max

By: bob

bob — Tue, 14 Aug 2012 20:16:11 -0700

hi,
i have a solar system & i am using a device that measures the voltage of the batteries and send it through a serial port to the computer, that can show me the health at anytime of the day.
i have 8 batteries connected in parallel, and the problem that i am trying to think of a solution is that the measuring device is treating the 8 batteries as one, and gives me a single reading. But in order for my monitoring project to work, i want to be able to measure each battery alone, even when they are connected in parallel together…
I know this sounds impossible, but I still need to think of all possibilities.
Anyone with any clues would be very helpful.

Thanks.

By: Bob

Bob — Sat, 11 Aug 2012 19:17:54 -0700

Hi, First of all I want to say that your tutorials have been very useful for me and I have learned very much.

I have an off grid house that I power with four 12V 245AH 8D AGM batteries wired in Parallel which are connected to a xantrex 3000W sine wave inverter/charger. I have a xantrex link pro battery monitor that has a programable alarm relay that I have set to start the generator when the batteries get down to 55% state of charge and to turn off again at 85%. occasionally I turn the generator on manually to bring the batteries up to 100% charge to synchronize the monitor. I just set the system up a few weeks ago and it is working very well so far. I am not there very often but whenever I check on it, the batteries are within range and the generator runs for 4 or 5 hours a week. The only thing running while I am gone is the refrigerator and a half dozen 7w led lights that I have come on after dark. I don\‘t have any other source to charge the batteries yet (solar or wind).

I have a couple of questions:

Do you think this system will work well in terms of longevity? Is there something I should be doing differently, such as setting up the monitor to keep the batteries at a different state of charge (more or less discharge)? The reason I don\‘t bring them to 100% every time is that the generator needs to run for quite a long time to get the extra 10-15% into the batteries and it seems like a waste of fuel.

Second, if I had an always on wireless internet connection, do you know of a way that I could monitor the battery condition from far away via the internet? So that I would know if there was a problem with the generator not coming on. I don\‘t know if there is a battery monitor available set up to do that. Any ideas you might have would be geatly appreciated.

Thank you.

By: Bill

Bill — Fri, 03 Aug 2012 14:01:50 -0700

I have an old (‘85) Honda ATV. After some reading (obviously not enough)I purchased a gel cell battery that was advertized as appropriate for my ATV. It did not take long for the battery to reach a point where it would light lights but not turn over the electric starter. After more reading, it would seem that the alternater would need some “adjusting” to keep this battery charged. I can find many references to external chargers, however I have, so far, been unable to find any information on what needs to be done to upgrade the charging system of the ATV for gel. Any help here?

By: Cpt Crunch

Cpt Crunch — Mon, 30 Jul 2012 00:42:30 -0700

THANK YOU FOR SHARING YOUR KNOWLEDGE! WOW! I have been working with batteries for years, yet never really understood their differences, much less how to match them with various applications. Here I have been buying based on the highest amp/hr AND CCA, when I should be looking harder at one or the other. And now there‘s an AGM???

Okay, ….a question:

The GPS/Fish Finder on our boat uses around one-third of an amp. My typical day of ocean fishing is between 8 and 10 hours. I do not like it on the starting battery and am looking for options.

The first question is AGM or a small gel cell? I am looking to understand the balance between them, in particularly, the lesser chance/lower cost of replacing it in the event I trash it, …which I am convinced is destiny – or the higher cost of a gel that I will not trash. (While I think I am very easy on batteries, evidence shows they do not seem to like me.) So, is it just math, or are there other considerations I should be looking at?

If using an AGM, the YT4L-BS will give me 9 hours of GPS. Correct? Or should I be looking at double that size, like the YT6.5L 12v AGM? I just cannot see spending $140 for something a 41 battery will do just as well for.

Prior to reading your pages, I had heard of AGMs, but the information was skewed. I was told they are just like gel cells, which I now know is only a half-truth. I can clearly see the differences over wet and gel, but I am most attracted to the low replacement cost if I, indeed, trash it.

Which one do you recommend?

Again, thank you for the site, …and I welcome your sagacity.

By: Steve

Steve — Wed, 25 Jul 2012 14:18:50 -0700

Thank you for your great information. It always helps to read it rather than using guess work!
I do have a question for you that I hope you can help with please.
I have had our motorhome for nearly 2 years and it came with a couple of solar panels – one of which is rather large. However we have had a couple of problems with cooked batteries! Basically, we discovered our battery was being cooked by one of our solar panels as the regulator was not working. We got that sorted and replaced the very smelly leisure battery. But just recently the same thing happened again and we discovered that our very large solar panel didn‘t have a regulator on it at all. We realised very quickly and disconnected the battery which was beginning to sulphar up and smell. We have since added a regulator and although the battery was able to be cleaned up we are finding that it now will take a decent charge but is only holding that charge for about 45 minutes. So we have 2 great solar panels and no holding charge. Do you think that this is due to the damaged battery or could it be something else? It is a sealed battery and so we cannot tell what state it is in internally. Thank you.

By: Roger

Roger — Sun, 22 Jul 2012 09:07:14 -0700

A really helpful, first rate site. Thanks! My question relates to appropriate charging of an AGM (or alternatively, a Gel) battery on a vintage, generator equipped car. The generator and standard regulator setup are inadequate to operating the car with headlights AND, say, windshield wipers or heater blower. The set-point of the regulator has to be raised to 16 volts to avoid battery drain whilst driving, and so after starting, and within about 5 minutes, as the voltage reaches 16, I switch on the headlights to load the generator down to about 14.5 volts. After several hours drive, or when other loads are added, this voltage will fall below 14 volts. Is this procedure good enough to maximize the life of an AGM or Gel battery? An alternator conversion is being considered. Comparing say a Delco 10Si with a Mitsubishi that might be used for tractor or marine purposes, what should I be careful about? I am thinking of the different battery applications, tractor, marine, etc, versus the Delco regulator of 14.4 volts. Thanks.

By: Bill

Bill — Sat, 14 Jul 2012 09:40:53 -0700

May I charge a 6v auto battery using a 12v (rated) solar panel?

By: Marissa

Marissa — Fri, 13 Jul 2012 18:49:19 -0700

I just bought a JL 50 scooter and the battery it came with is a12. Battery which came with the liquid which instructed me to put liquid into the cells and then cap it with the plastic cap plate that came with it and then charge fully before using. I filled it with the liquid two days ago but have not been able to go buy the charger which I Plan on buying at wall art tomorrow. Last night and one time today the battery cell cap has popped open on only one cell (the last one) loud enough for me to here it ( it is in the same room with me). I am worried something is wrong, should I be concerned? Is this normal ? Is it because I squeezed the bottles when adding the liquid?

By: Francisco

Francisco — Tue, 10 Jul 2012 11:37:46 -0700

Can I charge a wet lead acid battery SLI in paralel whit a AGM deep cycle whit only one alternator?
A relay disconnect de paralel when the motor is off.

Thanks

By: Trevor

Trevor — Sun, 08 Jul 2012 14:12:32 -0700

Shouldn\‘t this battery be dead? Why is it working?
I just bought a 12v 7.2ah Valve regulated Lead acid battery for $5.00 I tested the volts and it\‘s at 12.75 a sticker reads \“Top Charge Date 4/26/2007

I ran a motor from it for 2 minutes and it held up. I charged it and it took a charge. Should I run a cordless drill motor from it for as long as I can to see how long it last? Or should I leave well enough a lone?
Thanks Trevor

By: Kyle

Kyle — Sat, 30 Jun 2012 00:29:23 -0700

If you have a bunch of 12V deep cycle batteries paralleled (or groups of series 6‘s then paralleled to make 12V) – is it best to isolate each group so that at night the batteries are not fighting each other. I mean isolation as in commercial heavy duty battery isolators. Is this much more necessary if the bank is not typically receiving a daily charge top up (i.e. solar)?

By: marv

marv — Tue, 26 Jun 2012 07:20:54 -0700

I BOUGHT A LIKE NEW HOVEROUND FOR 3.00 ON A GARAGE SALE. IT WASNOT USED MUCH AND THE BATTERIES WILL NOT CHARGE WITH ON BOARD CHARGER. I DID GET ONE TO CHARGE WILL ANOTHER LEAD ACID CHARGER ON 2 AMPS OVER NIGHT THE OTHER BATTERY SHOWS ONLY 7-8 VOLTS AND IS STILL CHARGING NOW 2 DAYS.
CAN I DO ANYTHING TO BRING BACK THIS BATTERY? OR DO I NEED TO BY A NEW ON. I ADDED A LITTLE WATER TO THIS BATTERY EVEN THOUGH I KNEW IT DOESNT TAKE WATER WILL THIS HURT IT IT DOESNT CHARGE COMPLETELY ANYWAY.
can i use lead acid batterys in this hoveround to get it going to test it?
LET ME KNOW IF YOU CAN HELP
THANKS
MARV

By: Steve Tannenbaum

Steve Tannenbaum — Fri, 22 Jun 2012 16:18:13 -0700

I have a question about battery charging from a solar panel. The solar charge controller uses a mosfet to act as a switch. If the voltage on the battery increases to a certain level, then the mosfet opens and disconnects the solar panel. What happens if my solar panel puts out 24 volts instead of 15-16 volts? Will the higher voltage but lower current of the panel cause any charging problems?

By: Josh

Josh — Fri, 15 Jun 2012 10:36:40 -0700

in a 24 volt system, batteries connected in series, if one battery happens to fail, should both batteries be changed regardless of whether or not the 2nd battery tests out fine? also, in the same system, if one would be required to boost the 24volt system from a another source being a 12 volt source… does one connect battery positive from boosting source to battery positive of battery require boosting, negative to negative of only one battery?
This seems like it could cause a problem as battery 1 is connected to battery 2 in series which means, battery + of one is connected to battery – of the second, wouldn‘t boosting cause problems?? how does one go about doing this safely to himself and the machine being boosted.

By: graham bennett

graham bennett — Thu, 14 Jun 2012 01:28:21 -0700

Dear Sir,What is the best/correct proceedure when charging a 12v battery,used for a golf trolley.When fully charged,is best to keep it on charge,or remove it from the power supply?. Thanks.

By: graham bennett

graham bennett — Tue, 12 Jun 2012 03:14:50 -0700

My question is,do you keep a 12volt battery(used for a golf trolley)constantly on charge,or remove from charge when fully charged?.thanks.

By: tim

tim — Sun, 10 Jun 2012 13:06:42 -0700

I live in a 3rd world country. Distilled water is not available here. Can I safely use the water out of my Katydyn Filter to add back water to my starter battery? The water going in is either rain water or river water; it is not treated chemically. If it is not acceptable for the battery, what are my options for adding water to the battery? Thanks in advance!

By: Fred Harris

Fred Harris — Sat, 09 Jun 2012 07:13:55 -0700

Great article, Learned much, but, and there is always a but, started looking at batteries and found the amp hour rating listed in different ways – examples:
20 amp hour rate:55
35 Amp Hour
32 Min @ 10 Amp
So I am again confused about the true meaning of the amp hour.
I think this is what I need to look for as I am looking for batteries for a trolling motor.

By: Art

Art — Tue, 05 Jun 2012 05:08:13 -0700

I have two deep cycle dp24 12 volt batteries. One is rated 685 CA 32degrees and the other is 505 ca 32 degrees, the first is rated at 140 minutes and the other is 120 minutes. Can these be connected in parallel without problems? Can they also be charged in parallel using one charger?

By: Gary Mack

Gary Mack — Sun, 03 Jun 2012 21:14:57 -0700

I have recently purchased four new US Battery 12V Deep Cycle golf cart batteries for my 2006 Club Car, which has a 48V motor. I don\\\\\\\‘t drive the cart more than 1-2 miles on a given day but always recharge the batteries every day of use. The Club Car charger is left plugged into the cart at all times the cart is not in use. I am getting an awful smell after the meter on the charger drops to about 4 amps…on its way to zero on the charging cycle. I can hear the electrolyte bubbling inside the batteries and they do not get hot whatsoever. Once the meter reads zero amps and the charging cycle has ended, the smell stops. Is this normal? Factory personnel tell me they will always smell when recharging…..but I have never experienced this with former Trojan (Club Car) batteries. The local dealer says the smell should stop shortly…otherwise there may be a problem with one of the new batteries. My voltmeter shows 12.7v in each of the four batteries after charging.

By: Carlos

Carlos — Mon, 28 May 2012 12:16:46 -0700

I have four 110AH leisure batteries for my small hybrid solar system. The batteries are all 2yrs old and are not holding their charge like they once did. I read somewhere that I could empty and wash them out then replace with a mixture of sulphuric acid(96%) with distilled water to the correct gravity, put them on a trickle charge for 36hrs and then they will be better than new… Is this true? And if so, how can I be sure my mixture is correct? I do have a basic hydrometer. Many thanks!

By: Timothy Lee

Timothy Lee — Sat, 26 May 2012 07:27:51 -0700

I have a 12V marine deep cycle battery which is marked 875 marine cranking amps, 675 cold cranking amps, and 125 amp hours. I have been using the battery on my boat for about two years since I purchased it. It was charged every couple of months by either running the engine (a 9.9 HP outboard with an alternator which puts out less than 10 amps at full throttle) or by using a regular car battery charger with a pulsating charge of 10 amps(duty cycle= 10 sec. on, 140 sec. off). It only serves the bilge pump when the boat is not in use, and the pump only runs a few times a day for a few seconds. After not checking it for about two months, I found that my battery was not working (boat bilge was flooded) so I brought the battery out of the boat to my house. Prior to charging, it read about 6 volts on the meter, and it was low on water. Each cell had about 1/4 in. of the cell showing, and I added about 4 oz. of distilled water to each cell. I charged it for about 50 hours with the 10 amp charger, and after reading your article, I changed to a 1 amp charger. I now have access to a hydrometer, and I will stop the 1 amp charge tomorrow morning, and let the battery set for a while before checking with volt meter and hydrometer. The 10 amp charger still reads about 9 amps on its meter when charging, and immediately after I disconnected it, the voltmeter showed 12.46 volts. All cells were bubbling, and the battery was warm, about 100 F. What have I done wrong so far? Could I have damaged the battery? Do you think it will recover from the deep discharge?

By: mat

mat — Mon, 21 May 2012 13:00:12 -0700

is it possible to charge a 12 V battery with less than 12v?

By: vince

vince — Mon, 21 May 2012 11:20:05 -0700

I have a cpep that uses 2.2 amp I need to run it of a deep cell and a inverter for 8 hour for camping what what size inverter and deep cell battery would I need?

By: Justin

Justin — Sun, 20 May 2012 15:37:46 -0700

i have a 12 volt trolling motor and i just purchased an optima bluetop battery. These batteries are marketed as being dual purpose (deep cycle and cranking). is it possible to connect two 12 volt batteries to power my trolling motor (i want to be on the water as long as possible) and if so could i than use one of those 12 volt optima blue top dual purpose batteries as my cranking battery for my engine? if any of this sounds dumb im sorry im very new to boating and im trying to figure all this out .

By: bob

bob — Thu, 17 May 2012 18:46:06 -0700

The best ever. Your tutorials were written for dummies like myself.

By: Kamran Jabbar

Kamran Jabbar — Wed, 16 May 2012 04:23:09 -0700

When we use two batteries 12V each in a 24V system connected in parallel. There will be a possibility of unbalancing if both the batteries have different manufacturing date or batch. The charger only knows to charge 24V even if one battery is at 14 and other one is at 10. So it is thumb rule always connect same batch batteries in series and never replace one battery in a series. Replace the whole bank to avoid unbalancing. Unbalancing can damage one battery earlier than expected life.

By: yloon

yloon — Mon, 14 May 2012 22:35:04 -0700

I have been charging my dead battery for 4 months using pulsetech smart charger. This dead battery has been leaving there for 1 year.
I got back my voltage of 13.7v and the smart charger is pulsing without mass charging for 1 week.
However the battery still unable to start my car. The battery can supply headlight, horn and etc.

Should i give up this battery or any other way to try it out?

I notice 1 of the electrolyte\\\‘s in a cell is not drying up even after a long charge. the other cells always keep drying up and require to top up with battery water. Is the cell dead and cannot be revive anymore?

thanks.

By: S.

S. — Wed, 09 May 2012 16:09:09 -0700

My husband just added acid instead of distilled water to my motorcycle battery after it had been sitting all winter. Is it ruined?

By: jim

jim — Tue, 08 May 2012 11:48:10 -0700

Off the beaten track but several years ago my Dad bought me a 16V Craftsman drill. I used it a couple times and put it in the garage. Recently I was cleaning up and found that drill but the battery was dead and refused to take a charge no matter what. A new battery (when they can be found) is $55 plus. Do you know of any way to get this battery working again? Thanks.

By: Jack gilbert

Jack gilbert — Sat, 05 May 2012 20:09:46 -0700

Great info, my battery died today, so, the AAA guy said that my old battery was below 12.5 volts and that it wouldn‘t have or hold the amps?? what does this mean

By: trev

trev — Mon, 23 Apr 2012 21:51:33 -0700

i might have missed this in the article but, why is it not recommended to mix battery sizes, and not to mix battery types?
cheers

By: Dave

Dave — Fri, 20 Apr 2012 15:29:36 -0700

I have a question. I purchased a Minn Kota Endura 50 trolling motor 2nd hand. It‘s for an aluminum fishing boat I have access to once a year for a week. I‘m a casual fisherman who takes the boat out maybe for an hour a day. I bought a deep cycle AGM 12 Volt 12 amp hour with a charger for agm and gel batteries. I had trouble finding what kind of draw the trolling motor places on the battery at the Minn Kota site. Did I buy an undersized battery for my causal usage?

By: Bill

Bill — Mon, 16 Apr 2012 13:15:56 -0700

Hello,
I asked a question a few weeks ago and have been looking for a reply. My question is about running LED lights on a 12v vs a 24 volt system. I have 17 lights that are 27 watts each and want to get the maximum runtime. I have seen your calculators but do not have all the imput parameters. The batteries I am thinking about are deep cycle with 210 reserve capacity. Thanks.

By: Frank

Frank — Mon, 16 Apr 2012 09:30:11 -0700

Virgin lead vs. recycled lead?

Is there a life span difference between batteries constructed with virgin lead compared to one made with recycled batteries, assuming that all other conditions are equal? If there is a difference, is it a noticeable one?

By: Budge

Budge — Tue, 10 Apr 2012 12:27:46 -0700

I have a 12 volt portable battery (Sears Diehard Portable Power 1150) that I use for car camping trips and the occasional jumpstart. I wasn‘t keeping it charged all the time and the battery finally wouldn‘t take a charge anymore. So I was convinced to replaced it with a deep cycle agm battery. After reading your article, it seems apparent that I should not have used a deep cycle because it‘s not appropriate for jumpstarts. However, I have also found that after the first time I used the battery for a weekend of camping, I had drained it down to 10% and now it will not charge. Is it possible that the unit is not compatible with deep cycle batteries, or is it more likely that I overdrained it and the unit isn‘t registering a battery to charge? I was told that I can connect this unit to my car battery (or any other charged 12 volt battery) and that should trick the unit into charging the battery. What do you think?

By: Tom

Tom — Mon, 09 Apr 2012 04:38:26 -0700

Lots of good stuff here—-and well written so that weekend mechanics like me can understand it. I have a 36v Western Golf Car with 2 year old batteries. The charger came with the car and I recharge after every use. None-the-less, two cells have failed on each of two of the batteries. Your article recommended that I should not \‘mix and match\’ batteries, but I would like to replace the two failing batteries with new ones to get another year or so out of the remaining 4 old batteries. They cost about $125 each so my fix would invest $250 now to stave off a $750 pay out for another year. Bottom line: If I follow your advice, I replace all batteries at the same time and chuck 4 fairly good batteries (with no resale value). Is there a middle ground—-such as using some of your products to bring the two batteries back to service??

By: chad

chad — Sat, 07 Apr 2012 13:16:15 -0700

Excellent information. Thanks.

Just bought a DieHard Platinum Marine Group 31 for my boat. The reviews on this battery are excellent and I plan to use it for both starting the boat and running the trolling motor. You mentioned needing a special charger for AGM batteries. I have a Stanley BC4009 40 amp 3 stage charger. Is this charger OK to use with the AGM battery? Do I have to disconnect the battery from the power cables to charge it? Thanks for your help!

By: bobby

bobby — Sat, 31 Mar 2012 06:46:45 -0700

A very useful site, and highly informative – well done!

I have two flooded lead acid for my domestic bank, and have added a small AGM for the engine start. The mains charger can be configured for one type or the other – in my situation would it be better to set the charger to AGM type?

bob

By: Rich

Rich — Wed, 28 Mar 2012 07:23:36 -0700

James,

I have a boat with 2 cyl diesel engine and currently 2 series 27 wet batteries set as two banks. I would like to add another 2 batteries because the engine does not start easily when cold. The question is whether it is advisable to mix AGM\‘s as one bank with wet cells as the other. I would like to change to AGM\‘s, but hate to lose the investment already made in the two wet batteries. For starting, I do have a standard A/B or BOTH as a switching option for the banks.

By: Bill Smith

Bill Smith — Fri, 23 Mar 2012 11:27:55 -0700

Thank you for that info. Well meaning folks online were driving me nuts telling me that a deep cycle battery that is often discharged to 50 percent will greatly shorten the life of a small alternator. But I couldn‘t find any info like that at a reputable web site and I‘m glad to hear it isn‘t really true. I had been looking at a VSR (voltage sensitive relay) for the part of the wiring you mentioned. These (I guess they are all the same) charge the starting battery first and then switch the charging current to the auxiliary battery. Does the isolator you mentioned work that way? If not, which method do you think is best. I know the companies that make the VSR devices are always touting the fact that there is no voltage drop with their devices which I gather there is with a device that uses a solenoid.

By: Andrew D-H

Andrew D-H — Tue, 20 Mar 2012 05:22:55 -0700

Awesome article – thanks. I have a question.
I have a YP17-12 (12V17AH) Maintenance Free Lead Acid battery in my Bushranger Power Tank (for jump starting). It‘s was showing over 12 volts after about 10 hours at 1 amp. I tried to load test (it failed) and it‘s now just under 12 volts. It has a plastic strip which when I popped it off with a screwdriver there were little caps on each filling hole. Can I add distilled water to it even if it had gel. I up-ended it with caps off over a container and not a single drop of liquid came out making me think it is not a wet acid type. Your thoughts would be greatly appreciated.

By: Shawn

Shawn — Mon, 19 Mar 2012 12:04:33 -0700

The article above suggests you know what you‘re talking about. I don‘t know jack, but have read a little online and am trying to use a deep-cycle battery to power a projector for a public art project. Any chance you‘re available to help me trouble-shoot? I borrowed a neighbor‘s charger and charged a brand new battery up for about 15 hours. I then hooked up a 1000watt inverter and plugged the projector in. It worked great, for about 25 minutes, but then just died with a Low Voltage error message. Does this mean the battery wasn‘t charged all the way or am I doing something else wrong? According to the projector specs, the max wattage it uses is 288. Would really appreciate any input you‘ve got. I‘m out of my league here.

By: Cain

Cain — Sun, 18 Mar 2012 11:55:28 -0700

Hi,
I only use my car on weekends. My question is: Can I use a Smart Charger whenever the car is stopped? This will not overcharge the battery?
My car has an AGM battery.
Thanks in advance for your help.

By: Bill Smith

Bill Smith — Sun, 18 Mar 2012 00:40:07 -0700

Thank you for the excellent article and taking the time to answer everyone\‘s questions. I want to install a dual battery system in a small car that has an 80 amp alternator. The 2nd battery will be dedicated to one appliance that has a low current draw. A small deep cycle AGM like those used in mobility scooters will do the trick (about 35 Ah). I don\‘t want to upgrade the alternator but I also don\‘t want to overly stress the one I\‘ve got by having it regularly recharge a battery that is often going to be drained close to max (50 percent). Is there a way that I can limit the current to the second battery so that it charges at 10 to 15 amps? That would be equivalent to driving with lights on and so I know it would not have a big negative effect on the alternator as long as I am not using the lights.

By: gary

gary — Sat, 17 Mar 2012 06:33:47 -0700

have a 6 volt dry cell batt. in a old bike. is there a way of protecting the batt. from being over charged? thank you for your time..

By: Toni Roddey

Toni Roddey — Tue, 13 Mar 2012 14:19:49 -0700

Fantastic information. Thanks so much for your service to those of us struggling to understand through all the hype. My question is for a marine application. I have a bank of 4 Trojan lead acid batteries for my house bank and another lead acid starter battery. My starter battery died and I‘d like to replace it with a maintanence-free option but have heard not to mix battery types. I‘m not ready to replace the Trojans, so should I just buy another lead-acid starter to tide me over until my Trojans die? Thanks for any suggestions you can give.

By: Jummy

Jummy — Tue, 13 Mar 2012 02:49:52 -0700

hello Jamie, I am currently working on a research about Solar- hybrid off-grid instalations,
I have my battery amp hour for 20hrs discharge but i need the battery to store enuf cahrge for 3 days, so ut is trippled, do i still use the C20 rating or do i use the C72hrs rating for it? i am confused. and the needed Current is about 6000Amp-hour

By: mel schallot

mel schallot — Mon, 12 Mar 2012 10:46:00 -0700

Very good overview of lead-acid batteries. How do I submit a question? What type of sealed lead-acid battery would a handicap scooter likely have: AGM or Gel? I need to know in order to select the right charging mode for a Schauer automatic charger.

By: Deron

Deron — Mon, 12 Mar 2012 10:16:25 -0700

Next time simple is enough…..

By: Phyleus

Phyleus — Mon, 12 Mar 2012 03:30:44 -0700

Wonderful article. Just had a question though.
How does one test SMF batteries on-site for e.g. Server UPS batteries. ? The test-gig should be portable though.

By: Greg White

Greg White — Thu, 08 Mar 2012 16:21:59 -0800

James, this is a great site! Maybe you can help me: I have 3 8D AGM marine batteries on my boat with a xantrex charging system. The boatyard said they would plug the boat in over the winter in the warehouse but did not. Nor did they shut the breakers off. So, the batteries were depleted to zero over the last 5 months. How can I tell what damage was done? How can I calculate the liability the boatyard has?

By: Eagleye

Eagleye — Mon, 05 Mar 2012 17:33:07 -0800

Thank you James, for all the great information!

Ive got an electric scooter (xtreme xb-600) and need to replace the 12v22ah SLA. Ive looked around and was told that the EVX12200 or EVH12240 Deep Cycle Battery would be the way to go.

Your opinion would be muched valued and appreciated!

By: Rick Echols

Rick Echols — Fri, 02 Mar 2012 09:06:16 -0800

Hi, I have four 6 volt house batteries for my RV. We do some warm weather dry camping. How low should I let the voltage drop before recharging with the generator? Thanks, Rick

By: john paciorek

john paciorek — Fri, 02 Mar 2012 06:07:59 -0800

I have a Sportster scooter which is seven years old and has two 12V deep cell GEL type batteries. It has been used very little. These batteries won‘t take a charge. When I disconnect them to read the voltage I get 11 volts on one and 13 volts on the other. Gel types (80AH) for this unit are super expensive.
(1)Could I try to replace the 11 volt battery only, presuming its a dead cell?
(2)Would you recommend that I replace these batteries with two AGM batteries with a comparable AH rating? Can I use the same charger on these batteries?
(3) Any other way out of this dilemma, such as using a maintenance-free lead acid battery with a comparable AH?

Thanks very much, John
Thanks very much

By: Tom Z

Tom Z — Wed, 29 Feb 2012 09:55:06 -0800

I have an interesting battery question for AGM battery charging. I recently purchased a 12 volt 7 amp battery for my roboduck, I used my older 1/2 amp charger adn about two hours later, I noticed the battery had a puddle of clear water around it\‘s base. It was acid! How on earth could a glass matt battery generate that much fluid (about 1/4 cup). I did nto even think there was that much fluid in the battery! What is going on?

By: Yancy

Yancy — Fri, 24 Feb 2012 11:33:54 -0800

I‘m shopping for a couple of off-grid batteries , I‘m curious when purchasing a new battery, what is the typical warranty length, in case you bought a dud that was sitting in the heat in storage for 12 months. Thanks, great info BTW

By: John C

John C — Thu, 23 Feb 2012 17:43:46 -0800

Great informative article. Just wondered if you or any of your readers have experienced or heard of problems with BMW automobile batteries? This is a well know and documented issue by many BMW owners and dealers? Due to the inordinate number of battery life failures BMW no longer honors their new car battery warranty. By downloading historical information from the automobile\‘s computer the dealer will look for any excuse for blaming the problem on the car owner, e.g., leaving the door open, leaving the key in the car, or not driving the car for several weeks. It seems to me that BMW has a problem with parasitic drain on their cars from about the time that the 2008 models came out. The car computer remains active when the engine is off, still controlling functions that I cannot explain. BMW has not compensated for this parasitic drain by installing a heaver duty (more Amp Hours) battery. I can\‘t believe their engineers are this ignorant. An easy saluting would be to parallel two batteries but this would increase the cost of the vehicle by several hundred dollars. That is probably why BMW has taken no action to correct the problem. It is possible that other automobile manufacturers have similar problems. My opinion is that if new batteries cannot be designed to compensate for the heavy parasitic drain then the manufactures need to install two parallel batteries or come up with procedures to connect an external battery trickle changer when the car is parked overnight.

By: Todd

Todd — Wed, 22 Feb 2012 18:21:02 -0800

I am purchasing a 125 watt solar panel and want to purchase two 12 volt RV batteries.I dry camp alot and want to be able to maximize my reserve capacity using the solar charging to replenish the drain on the batteries. My question is what size battery re the 20 hr amp rating would you recommend using two twelves and AGM or Gel? I do not winter camp so majority of use is April to Oct. Apprecite your expertise.

Thanks TP

By: Z

Fri, 17 Feb 2012 04:37:09 -0800

I have a few questions about sulfation removal.

1. How can a person determine how much sulfation has occurred inside a battery?
2. Which de-sulfation device do you most highly recommend to remove sulfation from battery plates?
3. How much time is required to fully de-desulfate a battery? If the de-sulfation device isn‘t capable of fully de-sulfating a battery, can you let me know how much de-sulfation such a device can provide.

Thx, Z

By: kris f

kris f — Thu, 16 Feb 2012 01:10:58 -0800

hey, i am trying to charge 2 deep cycles in parallel with a 6 amp charger (12v) is this any diffrent than charging a single?

By: Denise Keilholtz

Denise Keilholtz — Tue, 14 Feb 2012 16:31:30 -0800

hi I am extremely interested in the subject and would like to thank you for clearing up a few things that i had previously not known.

By: Bob G

Bob G — Thu, 09 Feb 2012 14:20:56 -0800

Two weeks ago I purchased a new car Buick Enclave that had been on the lot for an extended period of time. Everything seemed to be fine until I took a long trip (10hrs). The next morning I used the remote start to warm up the car then turned it off and continued to load the car using the remote hatch lift several times. About ten minutes later I got in the car and didn‘t have enough battery to start it. I was able to get a boost to start the engine and return home (10hrs). I took the car to the dealer the next morning to have it checked out and was told the battery was good as it checked out at 12.3 volts. Doesn‘t that show a discharged battery? Should the charging system maintain the battery at 12.6 to 12.8 volts? The next step is to have the electrical output checked. I would appreciate your input as to what I should have them check next. Thanks

By: Bert

Bert — Sat, 04 Feb 2012 17:19:46 -0800

Hi, I have an older 4 ×4 truck with no electronics. However, I have an inverter to power (mainly laptops, gadgets), two external lights but no winch. My current alternator is rated at 75amps and my current battery at 80ams / CCA 780 / CR 120. I want to install a split batteyr system (solenoid+monitor) along with another batter (same power or slightly higher). Do I need to upgrade my alternator.. say to a 100 amps? Can a 75amp alternator comfortably charge both batteries..given than I\‘m using a \“smart\” split battery charging system? or am I asking for trouble….ie: a dead alternator? Thanks

By: JAYANTI

JAYANTI — Thu, 02 Feb 2012 03:31:52 -0800

Very important article on rechargeable batteries.

We are planning to install Lead Gel batteries in our AS/RS equipments. Shall we go for Lead Gel or AGM type of batteries ? Why ? Give us advantages in terms of cost & safety while selecting the type of battery.
Pls help us to decide.
thanks

By: john

john — Mon, 30 Jan 2012 21:31:06 -0800

if i could rate your article out of ten, i would give it ten.
very informative alas i did not solve my problem
what is the method of getting a rechargable battery to hold charge,
will short overcharging periods do the trick?

By: Larry

Larry — Fri, 27 Jan 2012 07:15:22 -0800

Is it possible to have 12 volts from a battery and low or weak cca ? Also tell me if im thinking wrong , but I have theory , that a battery is allot like your arm , you arm has the 12 volts and the muscles in your arm potentially are your amps , you can with stand holding weight for a certain amount of time until you become weak and need to relax for a few moments before you can “crank” again , would you say that would be a good example if i were to try and explain how a battery functions to people who don‘t speak english ?

By: john hackney

john hackney — Thu, 26 Jan 2012 11:03:29 -0800

Over the last 40 years I have puchased endless numbers of leisure batteries for my caravans none have ever lasted more than 12 mounths althouth I have charged them regularly.My latest one has just failed after 6 mounths and the manufacturers stamp 15 indicates January 2005 surerly this must be one of the reasons they do not last the coarse.I have found out more about batteries since reading Battery Stuff.Com although I am a retired motor engineer,Well Done.

By: Keith Clemens

Keith Clemens — Mon, 23 Jan 2012 07:38:27 -0800

Just to let you know that your battery basics piece was well written and useful. I appreciate your hard work and your passion for your subject.

By: jimmy

jimmy — Sun, 22 Jan 2012 08:06:42 -0800

What is the connection to the battery tocharge a 24volt system

By: Desmond

Desmond — Wed, 18 Jan 2012 14:04:41 -0800

This is just what I need to give me confidence in dealing with a battery issue. Much appreciated.