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Gel vs AGM: Not Quite the Battle of the Ages, But Nice to Know

AGM Vs Gel Batteries Tutorial

What is the difference between gel cell and AGM batteries?

AGM (absorbed glass mat) uses special design glass mat designed to wick the battery electrolyte between the battery plates. AGM batteries contain only enough liquid to keep the mat wet with the electrolyte and if the battery is broken no free liquid is available to leak out.

Gel Cell batteries contain a silica type gel that the battery electrolyte is suspended in, this thick paste like material allows electrons to flow between plates but will not leak from the battery if the case is broken.

More often than not AGM Batteries are mistakenly identified as Gel Cell Batteries. Both batteries have similar traits; such as being non spillable, deep cycle, may be mounted in any position, low self discharge, safe for use in limited ventilation areas, and may be transported via Air or Ground safely without special handling.

AGM Batteries outsell Gel Cell by at least a 100 to 1. AGM is preferred when a high burst of amps may be required. In most cases recharge can be accomplished by using a good quality standard battery charger or engine alternator. The life expectancy; measured as cycle life or years remains excellent in most AGM batteries if the batteries are not discharged more than 60% between recharge. There are some AGM batteries we sell that offer excellent 80%+ deep cycle abilities.

Battery Tender Plus Gel ProfileGel Cell Batteries are typically a bit more costly and do not offer the same power capacity as do the same physical size AGM battery. The Gel Cell Battery excels in slow discharge rates and slightly higher ambient operating temperatures. One big issue with Gel Batteries that must be addressing is the GEL CHARGE PROFILE. Gel Cell Batteries must be recharged correctly or the battery will suffer premature failure. The battery charger being used to recharge the battery(s) must be designed or adjustable for Gel Cell Batteries. If you are using an alternator to recharge a true Gel Cell a special regulator must be installed.

If you are unsure which battery or charger is best for your application, please call or email our tech people for help making the correct selection

Shop Gel Cell or AGM Batteries

112 people commented, TECH, Ron Hancock, Ronni1ewix, Tech, and 108 others
This article is rated 4.6 out of 5
For Questions and Tech Support, please submit your question with our Support Page.

Should contain only letters, numbers, and (' - .)!

   1   2   3   4   5

  • Ron Hancock
    Which battery is best for my 07 rv? I want something better then flooded batteries. I have a Wfco wf-8945pec converter in my camper.

    Reply  •  Rated article 5  •  March 23, 2023 at 5:09 pm
    • TECH
      A gel battery would be the best if you want the highest cycle life. However, they can not hold under load when excessively discharged, as well as an AGM can. If you know you are going to discharge your battery excessively then an AGM would be the best battery.

      Reply  •  Rated article 5  •  April 28, 2023 at 9:03 am
  • Ronni1ewix

    Reply  •  Rated article 5  •  September 24, 2021 at 2:06 am
  • Ron
    On my battery charger. It gives me a choice of automotive, standard gel and on other with initials. I have a seven year old craftsman riding mower. Where on the battery can I find it’s true name?

    Reply  •  Rated article 5  •  May 27, 2020 at 11:09 am
    • BatteryStuff Tech
      Realistically, older chargers like that may or may not work for a lawn mower battery. Most lawn mower batteries are about 30 AH battery, and some of these older chargers output 10 amp or higher. Ideally for a 30AH lawn mower battery it should be charged with a 3 to 5 amp charger, but may be charged with a charger up to about 7.5 amps. I think you may need to do a little more research to see what amperage your charger is outputting. Most lawn mower batteries are a flooded battery, but you need to find that information on the battery to be sure, or contact the manufacturer of the battery if you cannot tell.

      Reply  •  Rated article 5  •  June 15, 2020 at 12:57 pm
  • Tim Caruso
    Where can I find this Gell cell special Regulator for my boat, I have a 65 amp alternator and want to charge two gel cell batteries ( one starter and one house) and they are currently hooked up to a blue sea “add a battery “ switch and automatic charging relay.

    Reply  •  Rated article 5  •  May 20, 2020 at 4:42 pm
    • BatteryStuff Tech
      Unfortunately, we do not sell alternator or regulators, so I would suggest contacting another source. I would also verify your battery type is really a true GEL battery. Sealed AGM's such as Optima batteries and Odyssey Batteries are often mistaken for gel batteries when they are actually an AGM. Most starting sealed batteries are typically an AGM's due to their high cranking abilities. Gel's are typically not starting batteries since their chemical reaction is slower, so they do not have high cranking.

      Reply  •  Rated article 5  •  May 21, 2020 at 9:13 am
  • Lowell Schnipper
    I am buying batteries for use in a hospital in sub Saharan Africa. Non gel batteries are less costly. They currently use gel batteries. Which is preferred for this environment?

    Reply  •  Rated article 5  •  February 25, 2020 at 5:28 am
    • TECH
      Gel batteries are better in higher ambient temperatures. If they are going to be stored outside of a climate controlled room, then gels would be better in a warm environment.

      Reply  •  Rated article 5  •  March 6, 2020 at 10:08 am
  • Coza
    Great article, thanks.

    I want to use a battery as a leisure battery in a van (12v system). It will be charged using a voltage sensitive split charge relay. I live in Spain and it gets hot during the summer.

    1 Which is better, GEL or AGM (with heat, Split charge)?
    2 Is it a problem that the main battery is a wet acid one and the leisure a different type?

    Much thanks, Coza

    Reply  •  July 1, 2016 at 5:52 am
    • BatteryStuff Tech
      An AGM would most likely be your best bet, but be aware that most battery isolator require both batteries to be of the same chemistry, otherwise the isolator has difficulty charging them accurately. Most people go with an AGM, as they can also find an AGM type for the under the hood starting battery.

      Reply  •  January 19, 2017 at 10:40 am
  • Ernest
    Very good and informative article. Thanks!
    I left the key in my motorbike at ON position for a week or so (light on), and now my GS GT12B-4 battery, which I think is an AGM one, is at 1.2V. Do you think will I be able to recharge it? If so, which charging method should I look for or tell the tech to apply?

    Reply  •  Rated article 5  •  May 21, 2016 at 10:03 am
    • BatteryStuff Tech
      I would suggest a charging method similar to our Warranty Test we have online in our article called: How Does the Powersports Battery Warranty Work? You don’t need to worry about the volt readings, and if the battery at the end turns your bike over you know you have a good battery. If at the end it doesn’t then it is time to replace the battery.

      Reply  •  Rated article 5  •  May 26, 2016 at 8:00 am
  • Frank
    I am runing 24volt sukam inverter connected to a pair of 12volts 100AH powerwave AGM battery for 11 months now, but recently my battery charging time take les than 2 hour to fill up and the discharge time is also les than 2 hour why running same AC load that normally use to last for up to five hour. Thou for some time I’hve been using my 3kva gen to charge the battery throu my inverter due to reguler power failure, pls help is my battery dead or is d gen the problem

    Reply  •  Rated article 1  •  May 15, 2016 at 11:51 pm
  • JimT
    My question relates to using AGM batteries in an RV. Knowing that AGM and flooded batteries use different charging algorithms, is it a problem to use a flooded starter battery under the hood and AGM batteries for the house circuit? If so, which battery or batteries would be hurt with this set up?

    Reply  •  Rated article 4  •  April 23, 2016 at 12:32 pm
    • TECH
      If you want the altenator to charge the battery via a battery isolator then it is recommend to have the batteries the same chemistry, or risk damage to one battery. As far as what battery would become damaged I cannot say, but one will most likely get overcharged. My assumption would be the flooded, but it depends on the AGM as some AGM’s can take a much hotter charge.

      Reply  •  Rated article 5  •  April 25, 2016 at 8:57 am
  • Dale Doman
    What a great site. How refreshing to be able to read information that was readable, understandable and relevant.
    I started out just wanting to know the difference between acid flooded and gel and glass-mat batteries to be able to replace the oem battery on my motorcycle; ended up reading to the end. Very nicely done!

    Reply  •  April 12, 2016 at 7:41 am
  • Singh
    Hi, i want to install a deep cycle battery in SUV located in india. I live in uk and the car is run for a month or two in a year. I doubt if i could get an AGM or GEL in india, so may have to carry one from abroad. Reading your artical i understand AGM may be more transport friendly. I will check the same for Gel with the air authorites.
    I am wondering which battery would survive the heat of india? I am willing to install Gel as the charge will frequently drop below 50%. But will split charge system work with gel?
    Many thanks

    Reply  •  Rated article 5  •  November 28, 2014 at 10:30 am
    • BatteryStuff Tech
      Batteries in general do not like heat. When a battery is in an hotter environment the chemical reaction in the battery speeds up, and in turn increases the sulfation process. GEL batteries do tend to hold up a bit better in these conditions, but higher heat in general equals a shorter life.

      Reply  •  December 29, 2014 at 1:24 pm
    Good day to you. I bought two batteries (deep cycle) to operate my inverter, but after using it for 7months I observed a sharp drop in the in the battery performance. Presently, it can hardly serve for three hour with same loading that it use to take when it was new.i felt bad about it because it falls short of the assurance that the seller gave to me on the battery, hence I’m trying to find out from u guys about which one I should buy next that would at least give me value for my money.

    Reply  •  Rated article 2  •  November 22, 2014 at 3:18 am
    • BatteryStuff Tech
      I would recommend you use our Calculator | AC to DC amperage conversion run through an Inverter to determine if you are selecting the right batteries. You do not want to discharge a battery pack below 50% or you will be in essence taking life out of the battery.

      Reply  •  Rated article 5  •  December 26, 2014 at 9:22 am
  • Willem
    Hi,a question, I have 4 optima Yellow top batteries of 75ah, they will get charged by 3 solar panels, 480wp in total, so I need a solar charger/controller of 40Amps. The controller I almost ordered doesn’t have an AGM setting, only SEALED/FLOODED and GEL. Is this the wrong controller or what setting would be ok for AGM. Thanks.

    Reply  •  Rated article 5  •  November 18, 2014 at 8:41 am
    • BatteryStuff Tech
      I would contact the manufacturer of the controller, as most AGM batteries can be charged at the same rate as a Flooded. But do check with them directly to be sure they don’t have an underlined reason why they are not giving that option.

      Reply  •  Rated article 5  •  November 19, 2014 at 2:45 pm
  • Yasir
    I am glad to find this page and got many new information, I have been working on the solar projects and I have need to buy batteries from china for the systems, and this forum made my mind to take GEL batteries before that we were working on lead acid batteries.
    Sometime we have low power load like led bulbs and fan, but sometime we have heavy load for the batteries, what do you think GEL is suitable for these both systems ???

    Reply  •  October 21, 2014 at 4:05 am
    • BatteryStuff Tech
      span class="caps">AGM is preferred when a high burst of amps may be required, so if your high load fits into category then AGM would be the preferred battery.

      Reply  •  Rated article 5  •  November 18, 2014 at 12:41 pm
    I have a 40’ diesel pusher motor home with (2) 12 v engine batteries, (2) 6 v coach batteries, and (4) 6 v inverter batteries. the engine batteries are not a problem however the (6) 6 volt batteries are driving me crazy. I want what ever is best that is no maintenance. I have cooked more batteries by letting them run out of water than I care to admit. the coach might set for (2) or (3) months at a time which I normally leave plugged in so it stays charged. every now and then I will camp where there is no electricity and the coach batteries will run down low and then I will run the generator to recharge them.HELP – WHAT BATTERIES DO I NEED?

    Reply  •  October 8, 2014 at 2:01 pm
    • BatteryStuff Tech
      span class="caps">AGM batteries would be your best bet if you don’t want the hassle of maintaining the water levels. I would also look into your charger/converter to make sure it is at least a 3 stage charger. Often this is where manufacturers cheap out and only utilize a one stage chargers, which will burn out batteries, even AGM’s.

      Reply  •  Rated article 5  •  November 18, 2014 at 7:30 am
  • Al Miller
    great read thanks.

    Trying to retrofit dodge sprinter with auxillary battery for inverter, battery needs to go inside vehicle under passenger seat. want to use gel for fumes issue but alternator will charge both when isolator is on. any ideas on how to charge the gel seperatly?


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

    Reply  •  October 1, 2014 at 8:30 pm
  • Horace
    My god I am so glad that I finally found the answer for many of my question here regarding in particular the AGM batteries. Thanks os much for this well written and simple explained facts about the different types of batteries.
    I will like to buy me a battery load tester and was inclined to buy the MIDTRONICS PBT300. Reading reviews,someone
    is pointing out that this tester is NOT GOOD FOR AGM BATTERIES.
    Is there a valid reason for this statement?. Are AGM batteries different for load testing than others?.
    Thanks in advance for answering

    Reply  •  September 12, 2014 at 12:02 am
    • TECH
      A load tester simulates a load to the battery to verify that it is meeting its original design. It is not like a charger that needs to be set to a specific battery chemistry. However some of the higher end models might get into battery chemistry, so as always suggest looking at an owners manual before purchasing.

      Reply  •  Rated article 5  •  September 25, 2014 at 10:53 am
  • BatteryStuff Tech
    According to the info provided, you are looking at about 180AH to run that for 3 hours to 50% discharged. AGm would be recommended.

    Reply  •  June 27, 2014 at 8:45 am
  • Ihab Chaaban
    Hi, I have a 24V APS system and I use it for home lighting and watching TV. All lights and TVs are LED, and if I turn ON all lights and TVs at the same time (Full Load) the consumption is 3Amps AC output.
    1- what type of batteries do you suggest to use for this purpose?
    2- how many Amps hours batteries size I need to have at least 3 hours lighting for 50% battery discharge(take into consideration that I don’t need to turn ON all lights and TVs at the same time)

    Reply  •  Rated article 5  •  June 27, 2014 at 5:55 am
  • Chauncey M Freeman,SCPO,USN,RETIRED
    span class="caps">EXCELLENT, Just absolutely outstanding. Most articles require a soul to be a Rocket Scientist to understand what one is reading. Those such articles are usually written by people whom wish to sound to be more intelligent than they actually are. Thank you who prepared this article. I am in process of purchasing a VALDETTARO Built 190 Ton, 34 Meter Steel Sailing Yacht. One of the first things I shall do is get rid of all Her GEL BATTERIES and replace all with oversize AGM BATTERIES. I would love to locate an article that is just as well written as this one, but about the Real PROS and CONS of having SOLAR PANELS ABOARD for charging batteries. I cannot seem to get a straight answer on that subject, but with Solar Chargers getting better every day, it seems to this old Navy Senior Chief Retired, that there should be an advantage in having solar panels helping out that Diesel Fuel Guzzling Kitty Cat Caterpillar 3196 490 bhp. I do not know what I would do if that Kitty Cat required a sand box also. Again I say Thank You who did an excellent job writing the article comparing GEL Batteries to AGM Batteries. If I were still in the Navy I’d recommend you for a KITA. (Just Joking like all Navy Chiefs do) Chauncey M Freeman, Senior Chief Moanback, U.S.Navy,Retired (What did you say? What is a Senior Chief Moanback you asked? He is that Ole Chief standing down yonder on the pier shouting up to the Captain on the bridge of the IKE, “MMMOOOAAANNNBBBAAACCCKKK

    Reply  •  May 24, 2014 at 2:51 am
  • Chris
    What type of battery would you suggest for a classic muscle car with a 327 small block? Car only gets driven on weekends. And would a battery tender brand charger be a good choice to keep it charged?

    Reply  •  May 15, 2014 at 4:23 pm
    • Admin
      Chris, unfortunately, this falls outside of our expertise. The manufacturer should have a required CCA rating for the starter. The Battery Tender will work great.

      Reply  •  May 16, 2014 at 2:15 pm
  • Wayne
    Hi, I have a VMAX V30-800 AGM Battery 28AH Marine RV Deep Cycle HI Performance Battery used for a trolling motor. Can I use my Diehard charger to charge it? Settings are conventional or maintenance free / Deep cycle. Choice of 2, 10, or 50 amp (start) and is an auto charger.

    Also how long can I expect the battery to last just trolling around?

    Thank you.

    Reply  •  May 9, 2014 at 7:01 pm
    • Admin
      Please email with your question. thanks

      Reply  •  May 12, 2014 at 12:09 pm
  • Kevin
    Outfitting a VW non-camper van with an auxiliary battery system. Installed an isolator solenoid so that when the car is keyed off I can draw from the auxiliary battery using the inverter without working about whether my crank battery will go dead. When I key on, the isolator reconnects both batteries (through the fuse panel) and my auxiliary battery begins charging from the alternator. PROBLEM: the crank battery is a flooded battery and the auxiliary battery I installed is a gel. Can my alternator charge both the flooded and the gel as I’d hoped? Note that as soon as I installed the aux battery, my alternator failed…I think the voltage regulator in it went kaput. Waiting to install a new alternator until I know if my battery combination is just going to blow that one too. Thanks.

    Reply  •  April 26, 2014 at 1:19 pm
    • Admin
      Please email with your technical question.

      Reply  •  May 12, 2014 at 12:08 pm
  • Rita
    Very helpful, thank you. I use gel batteries in my electric wheelchair and my question is about storage. If I ‘store’ my chair (ie it sits in the carage while I drive my other chair) will the batteries be damaged in any way?

    Thank you.

    Reply  •  Rated article 5  •  March 17, 2014 at 12:27 pm
    • BatteryStuff Tech
      Rita, anytime you store a lead based battery be it gell, AGM or flooded, you will need to keep it charged or it can get damaged.

      Reply  •  May 12, 2014 at 12:07 pm
  • Sohail
    I’ve a 24V 1KVA UPS to compansate unplannedad load shading for domestic load. Previously I was using 2×12V flooded led acid batteries. But now I’m planning to install sealed batteries. 100Ah AGM and GEL batteries are available to me as linked But I’m confused about selection between AGM, GEL and floaded led acid one. UPS charger is 5 step stady current type, to charge boost and then floating. But all levels of charging voltage, current, discharging current and DOD are reprogramable.
    Here I need your help about
    1- selection of battery between three types
    2- if AGM or GEL type what would be settings of maximum charging voltage boost and then floating current limits and also set point for depth of discharge (DOD)

    Waiting for your response

    Reply  •  March 12, 2014 at 1:17 pm
    • Admin
      Please email the tech department directly with your question.

      Reply  •  May 12, 2014 at 12:06 pm
  • Tom
    Can I use gel battery for house bank and Agm for starting bank
    Port engine charges the house and starboard charges the cranking bank, however the onboard charger charges both banks from shore power
    The cranking batteries are gell now , but need replacing, they stopped taking a charge
    Both banks can be connected in an emergency
    AGM are half the price of gell and the diesels need a lot of amps to crank

    Reply  •  March 9, 2014 at 9:12 pm
  • Cane
    Excellent article.

    Reply  •  December 26, 2013 at 2:00 pm
  • Pablo Franco
    Excellent information, but I still have a doubt, when specified “Valve Regulated lead acid battery” which tipe it is? AGM, GEL or normal bat.

    Reply  •  Rated article 5  •  December 3, 2013 at 11:26 am
  • Arden Kasner
    Thank you for all your work explaining batteries in layman terms. You are an expert in your field and need to be recognized. This comes from a Delco trained repairman.

    Reply  •  Rated article 5  •  August 23, 2013 at 1:43 pm
  • Gary Weglarz
    Very Helpful.

    Reply  •  Rated article 5  •  May 24, 2013 at 6:16 pm
  • Tom
    hi,i am installing hydropower in my camp and in winter time i cant use but temp goes down to 20 to 30 below.wich type of battery would be best form my app.can i let them sit useless on low temp???

    Reply  •  May 10, 2013 at 5:33 am
    • Jeremy Fear
      Both AGM and Gel will work in up to (or down to?) -40 deg f.

      Reply  •  May 20, 2013 at 8:01 am
  • James Grove
    Can you mix GEL and AGM batteries in the same charging system? Ie Can you link 2 104aH batteries in parallel ?


    Reply  •  Rated article 5  •  May 7, 2013 at 11:28 am
    • Jeremy Fear
      That is not advised.

      Reply  •  May 7, 2013 at 2:27 pm
  • Bashir Adamu
    Folks. My battery application is mostly for solar remote lighting and power back-up in Nigeria. As discussed by some people earlier. AGM being more fluid in nature, responds better to high power draw than Gel that is more sluggish. However, for slower discharge like constant current (solar lighting for eg), Gel battery is far more superior, from my experience. But generally, Can those of you who think that AGM and Gel batteries have similar lifespans explain to me why the cycle life vs discharge depths (say 50%) reported by most manufacturers show a much shorter lifespan for AGM batteries than Gel?

    Reply  •  May 6, 2013 at 1:14 am
    • Jeremy Fear
      Gel batteries have the ability to discharge to a deeper level, approx. 80%, than AGM batteries. On the flip side, AGM batteries hold up to abuse much better than Gel batteries. If you take care of your batteries, Gel batteries have a very good cycle life.

      Reply  •  May 6, 2013 at 11:38 am
  • Larry
    What YTX9BS battery is recomended for my Honda EU3000is Generator ?

    Thank You LJD

    Reply  •  April 24, 2013 at 11:26 am
    • Jeremy Fear
      The Scorpion will work for your generator. :)

      Reply  •  April 24, 2013 at 11:48 am
    I have 2 100w solar panels with a 30amp charge controller. I was wondering if it‘s ok to connect it to a 31-AGM 12volt 100ah battery? will the charger controller be ok to charge this battery

    Reply  •  April 10, 2013 at 8:59 am
    • Jeremy Fear
      That will work to charge that.

      Reply  •  April 10, 2013 at 11:16 am
  • Andrew
    So long as 5 is the top rating as the stuff here is great and the tech excellent. I am just trying to work out what type of battery to put into my Moto Guzzi Le Mans. At the moment it is a Hawker Energy ODYSSEY – made in the USA. The Guzzi is getting a little slow to crank over so i want to know the best type of system to get. This has helped me greatly but if i could get some further guidance it would be great. The bike gets a reasonable amount of use and normally 100km/ride.

    Reply  •  April 4, 2013 at 8:24 pm
    • Jeremy Fear
      Odyssey batteries are excellend and should work well for applications where the OEM battery is hard pressed to start the engine.

      Reply  •  April 8, 2013 at 8:10 am
  • John
    I have just purchased a new caravan which is fitted with a 80AH wet cell and an MX25Charger (240V), a solar regulator that can be adjusted for different types of batteries, and is charged from the tow vehicle alternator when travelling directly. I am thinking of putting the wet cell in the car and purchasing a Gell or AGM for the van with a higher AH capacity. Would I have to change the MX charger (240V) and/or fit a regulator of some description between the alternator and battery?

    Reply  •  Rated article 5  •  March 22, 2013 at 4:39 am
    • Jeremy Fear
      You would certainly need an isolator of some sort to correctly charge the aux battery without over/under charging the starting battery, as well as to prevent the starting batttery from being leeched from.

      Reply  •  March 25, 2013 at 7:48 am
  • Anthony
    Looking for some help. I work for a company that sells commercial cleaning equipment and many of the machines use deep cycle batteries like the ones being discussed here. We have a customer who purchased a machine that came equiped with 2 12v “wet” batteries and a digital on-board charger. They would like to upgrade to AGM batteries. The machine has a dipswitch in the control handle that can be switched to “wet” or “gel” and the charger has a sequence of dipswitches that can be adjusted for either as well. Since there is no AGM option, would I be better off leaving the machine set to operate/charge “wet” or switching the settings to “gel”? Any advice is greatly appreciated!

    Reply  •  March 20, 2013 at 12:00 pm
  • Stratmann
    Hallo friends,
    some of your comments are not compatitable with my experiences. Let me tell following
    story: A user installed an AGM-battery into his emergency devices and after 15 years the battery was still working. He told it to his Golf-friends and every body installed
    such a battery into his caddy. But the life of this batteries was lower now than 1 year. What was the reason ? This user did‘nt tell his friends, that the emergency-case never happened and the caddyuser discharged and recharded every day.

    The lowest point of discharge should be 70 % from 100 %, because the deeper you discharge the shorter is the life of an AGM-battery. I try to explain this as follows:

    Real AGM-batteries are made with the same thin plates as for starting purpose. Very clear, because it is a Starterbattery which shall give high power and for this high
    power you need surface.
    Why do you want to pay for something, which you do‘nt need. For Semitraction purpose
    it is not neccessary to get high power. You need Ah, nothing else. If you have to chose between starting application and Semitraction applications than you should decide only between normal lead/acid and a GEL-battery. AGM is designed only for many electrical users and for start/stop, not for Semitraction. But this is, as many other things, mostly a question of experience. Who has the big pocket, can make expensive experiences. (Excused my bad english, I am only a German.
    Klaus Stratmann
    GELBatt GmbH

    Reply  •  March 11, 2013 at 12:22 am
    • BatteryStuff Tech
      span class="caps">AGM technology has nothing to do with the thickness of the plates. Your are correct, starting batteries have thin plates. Flooded, AGM, and even some gel batteries (rare) are made for these kind of applications.

      But flooded, AGM, and gel batteries are also manufactured for deep cycle applications, therefore they are built with thicker plates to sustain deep discharges. It really depends on the battery itself. Battery construction does not always define the type of application it should be used for.

      Reply  •  March 11, 2013 at 10:07 am
  • David
    I have four sollar pannels, rated at 15 watts each tied together going into a 7 amp regulator. There are four deep cycle 12 volt batteries that I run a 12 volt TV and a 100 watt inverter that runs my lap top. I now can not run my lap top off the 12 volt to 120 inverter. I have trouble with the batteries having dead cells. Is it something that I am doing wrong or is it bad battery? I would like to hook up a 30 volt wind turbine to the batteries, can I – should I? What should I do for this system so that I can have 12 volt power for the inverter and 12 volt TV to last through the night? Or to last a couple of days without sun light??

    Reply  •  Rated article 5  •  March 5, 2013 at 7:06 am
    • BatteryStuff Tech
      If your batteries have ‘dead cells’ then there is nothing you can do to fix it. I recommend replacing your batteries. By doing this, your inverter should work as intended and your problem solved.

      Also, charging a 12 volt battery system with 30 volts is too high voltage.

      Reply  •  March 5, 2013 at 9:20 am
    Can a gel battery be missed with Agm.

    Reply  •  February 6, 2013 at 3:05 am
    • BatteryStuff Tech
      We do not recommend connecting a Gel battery with an AGM. The discharge/re-charge will be uneven and it will lead to performance issues.

      Reply  •  February 6, 2013 at 9:14 am
  • Thomas
    Thanks for the info you have been a great help I learned things I didn‘t even know I needed!!!

    Reply  •  January 15, 2013 at 11:07 am
    • BatteryStuff Tech
      You‘re welcome. Thank you for reading our article. If it helped you, please share it with your friends!

      Reply  •  January 15, 2013 at 12:08 pm
  • Anon
    starting battery is a standard west marine wet cranking battery. I was under the impression you can‘t charge a wet and AGM together…Is this true? My starter battery is only a year old and works fine, but I want to add an AGM pure deep cycle for the house battery.


    Reply  •  January 2, 2013 at 9:58 am
    • BatteryStuff Tech
      It‘s not about whether or not you can. We just don‘t recommend it because it‘s not the most efficient way to construct battery banks. Batteries of different ages and types charge and discharge differently, and it can lead to uneven performance and early failure for one or both batteries. But technically it will work if you try to do it.

      Reply  •  January 2, 2013 at 10:07 am
  • Tom
    I have an Class B motorhome that I have used a 5 watt solar panel with no controlor to maintain the “chassis” battery when the RV is not in use. It is parked facing south and the battery has successfully been maintained for since 2007 without needing water. I hookup to power prior the departure for recharging the “house” battery which have been disconnected during storage. I also have a “cricket” (smaller that a golf cart) with 2 gel cell batteries in series for 24 volts. It has an onboard charger that charges the two batteries separtately (at the same time) when the indicator on the dash shows about 50% charge. It takes about 6-8 hours to charge the batteries. Your comments, please

    Reply  •  January 1, 2013 at 11:43 am
    • BatteryStuff Tech
      6-8 hours of charging is perfectly fine. What is it exactly you are inquiring about?

      Reply  •  January 2, 2013 at 9:59 am
  • Anon
    Confused if I can have a AGM house battery and a marine starting motor on the same 1/2 marine battery/charge switch…being charged by a decent size outboard motor.


    Reply  •  December 30, 2012 at 10:03 pm
    • BatteryStuff Tech
      You tell me, what is the issue with an AGM battery being connected to your Marine battery? Is your Marine battery a wet, AGM, or Gel battery?

      Reply  •  January 2, 2013 at 8:44 am
  • Frosty
    I have contracted to install a Generac 27kW liquid cooled emergency generator at my home in Virginia. Should it have an AGM or Gel Cell battery? The Generac automatically comes on for 1/2 hour once a week to check all systems (to make sure it is ready for use when an electrical outage occurs).

    Reply  •  December 29, 2012 at 2:44 pm
    • BatteryStuff Tech
      Do you already have a charger for the battery? If not, as long as the charger you buy is compatible with Gel then you can go that option. It really doesn‘t matter unless you absolutely need one of the following: a completely sealed battery, the need for severe discharge, or have extreme temperatures in your working environment.

      Reply  •  January 2, 2013 at 8:37 am
  • Robert
    Good info, thanks! I have a question. . . I put a gel cell in my 2003 HD Road King. Initially it did not hold a charge more than 3 days and I‘d put it on a 1 volt trickle charger overnight. It has worked fine like this for a year or so. After a few months I noticed the charge beginning to last a little longer, say, 4-5 days. Is this normal? Am I damaging the gel cell by trickle charging it with 1 volt? My ‘74 BMW needs a battery. I‘d like a gel cell for the maintenance free aspect but again wondering if I would damage the cell with a 1 volt trickle. All feedback is greatly appreciated. Thanks!

    Reply  •  Rated article 5  •  December 21, 2012 at 6:26 pm
    • BatteryStuff Tech
      It‘s probably a 1 amp trickle charger, not 1 volt. Your battery is a 12 volt battery, so it needs at least 12 volts going in. But the current (amperage) is the strength of charge. 1 amp is just fine for a gel motorcycle battery. If your battery is truly a gel-cell, then make sure your charger is compatible. Gel batteries should not be charged any higher than a rate of 14.2 volts. Regular non-gel chargers can reach as high as 14.6 volts.

      Reply  •  December 28, 2012 at 10:50 am
  • Randall
    Excellent write up!! Its nice to have a simple explanation. I bought a scorpion AGM a couple years back and have had no complaints. My only issue is something I did not know I caused until reading this. I eneded up installing a motorcycle alarm on my bike and not thinking I parked it in my garage for a couple months with out dissconnecting the battery. Needless to say the alarm discharged it and not thinking I figured I could leave a normal 2 amp 12 volt charger on it overnight. Well next morning my garage smelled awful, it was due to the battery being overcharged and boiling out what im now sure was the little amount of liquid in it. I admit this was all my fault as I did not think when charging it or parking it. Anyways looks like ill be buying another scorpion AGM and this time a battery tender to avoid this issue. Thamks for the write up! I now finally know what I did wrong.

    Reply  •  Rated article 5  •  November 23, 2012 at 7:16 am
    • BatteryStuff Tech
      Sorry to hear about the loss of the original battery, but we‘re glad the mistake will not be repeated in the future. :)

      Reply  •  November 26, 2012 at 1:11 pm

    Reply  •  November 4, 2012 at 4:35 pm
  • Vidis
    how do i determine how many amp hours i need for my 12v golf cart which contains eight batteries?

    Reply  •  September 30, 2012 at 5:02 pm
    • BatteryStuff Tech
      Can you confirm that your golf cart is a 12 volt system? Are the batteries 6 volts, 8 volts, or 12 volts? On average, golf carts run of 36 or 48 volts. But even if your cart does indeed run on 12 volts, I cannot tell you how many Amp Hours you need without knowing the draw amount and the duration of the draw.

      Reply  •  October 1, 2012 at 10:14 am
  • Anton
    I have a motorcycle in which I would like to put and AGM battery, but it seems like all the regulator rectifiers I get for it have a voltage setpoint of 14.7V, and they usually see 14.9 or 15 on occasion. Is this too high for use with an AGM battery?

    Reply  •  September 17, 2012 at 11:58 pm
    • BatteryStuff Tech
      High Performance AGM batteries like Optima and Odyssey can recieve a charge voltage as high as 15 volts, but I wouldn‘t put any other battery on it as it will be too high.

      Reply  •  September 18, 2012 at 2:49 pm
  • Rich
    I have a battery backup system in my home consisting of eight Trojan 105 six volt, 220 amp hr. batteries connected to a Trace SW4024 inverter/charger. I am no longer able to maintain flooded batteries, so I need to replace with sealed batteries. From your article, it seems that gel cell is better for my use than AGM, but I don‘t know if I can set my charger to accomodate gel. I currently bulk charge at 28.8 volts, with a float set to 26.8 volts. Can you tell me what my settings need to be if I go with gel cell and/or AGM?

    Reply  •  Rated article 5  •  August 6, 2012 at 4:16 pm
    • BatteryStuff Tech
      Those settings are fine for AGM batteries. If you use Gel batteries, the bulk charge should be no more than 28.4 volts. Floating at 26.4 is also good for Gel.

      Reply  •  August 7, 2012 at 9:28 am
  • Charles
    Which kinda batteries are best for a domestic/home windwill-energy solution‘s battery bank?
    THe installation is to be designed to function independent of the power grid. REcharging may have to be by a pms-run power generating set.
    Tis for a cabin that may not be on the grid in the nearest future.

    Thank you.

    Reply  •  Rated article 4  •  July 12, 2012 at 1:43 am
    • BatteryStuff Tech
      The best battery for long term storage and deep cycle is the gel battery. To determine how any Amp Hours worth your battery bank should be, please use our online tools. We have calculators to help you choose the correct battery size depending on the load amount.

      Reply  •  July 12, 2012 at 9:08 am
      • Tom
        span class="caps">LINK?

        Reply  •  February 6, 2013 at 9:53 am
        • BatteryStuff Tech
          a href="/kb/tools/calculator-sizing-a-battery-to-a-load.html">/kb/tools/calculator-sizing-a-battery-to-a-load.html

          Reply  •  February 6, 2013 at 10:28 am
  • Bbc
    if one is going to use a deep cycle battery for a trolling motor to putter a small boat around for a weekend, then reconnect it back to my diesel Suburban that already has two regular Interstate batteries, what would work best, AGM or Gell Cell, or Dry Cell?

    i will never know how much it gets drained while i‘m using it, but i figure it could get kind of low, like 30% or so…? (only a guess.) if the Gel Cells deal with this kind of use best, then i suppose i must go that route. but would i really have to have a special regulator installed on a Gel Cell?

    i used to have a massive Optima marine battery on a powerboat for years, then i wound up using it as i described above for another couple years. it eventually died, but i think i got plenty of life out of it. are Optimas Gel Cell or AGM?

    i‘m so confused about which way to go. i wasted $90 on a cheap deep cycle battery from O‘Reily‘s which only lasted a handful of re-charges, and i don‘t want to make the same mistake again.

    thank you all so much for all the help — this is a great resource!

    Reply  •  June 17, 2012 at 6:00 pm
    • BatteryStuff Tech
      For deep discharge, Gel is the best way to go. Regular charging systems will charge at a voltage that is too high and will damage gel batteries. Gel compatible chargers will charge usually no higher than 14.3 volts. With AGM, I recommend no more than 50% discharge. Optima batteries are AGM.

      Reply  •  June 20, 2012 at 8:36 am
  • Tim
    How do I know when my AGM battery is 60% discharged or 80% discharged etc?

    Reply  •  June 11, 2012 at 11:37 am
    • BatteryStuff Tech
      Here is some helpful voltage ranges. 100% charged is 13.2V-12.8V. 75% is 12.4 V. 50% is 12.2 V. 25% is 12.0 V. Anything lower than 12 volts is extremely discharged and should be re-charged as soon as possible.

      Reply  •  June 12, 2012 at 12:47 pm
  • Capt. Mitch Witt
    In the mid to late 90‘s Gel Cells were state of the art. The ARE FAST recharge and offer charge and discharge profiles and life spans superior to lead-acid. Gel Cells are still premium choices particularly for “house” loads (slow discharge rates).AGM‘s are technically not as great as sales figures would
    indicate. Some charging systems sold in the mid to late 90‘s which have a programmable setting for Lead Acid and Gel Cells will NOT work for AGM batteries. If the charger manual does not offer a specific setting for AGM don‘t buy AGM, they will be ruined by improper recharging. Some technicians offer he advice of setting your programmable charing system to “lead acid” for an AGM battery. This does not work. If the equipment was not specifically designed to accomodate AGM batteries – don‘t buy AGM batteries.

    Reply  •  May 31, 2012 at 6:09 am
    • BatteryStuff Tech
      Using the lead-acid setting of a charger will bring charge to an AGM motorcycle battery. It‘s not going to reject it. However, high performance AGM batteries, such as Odyssey and Optima, have shown to last longer if charged with a higher voltage than what is considered safe for wet-cels and gell batteries. This “AGM” setting is nothing more than a higher voltage, as high as 15 volts sometimes, just as the “Gell” setting is a safer lower voltage, 14.3 volts tops, usually.

      Reply  •  May 31, 2012 at 8:26 am
  • Jerry Filson
    Hi — I have an Optima 6-volt battery in my Model A Ford. Which charger do you recommend to recharge/maintain it? Thanks.

    Reply  •  May 21, 2012 at 12:23 pm
  • Steve
    Brilliant exchange – especially for a newbie. Many Thanks!
    I have a Gel vs AGM dilemma. Just bought a sort of neglected EV – no gas engine in this baby.
    The 6 battery bank is Gel but I have (at least)one bad battery. I realise I cannot replace the duff Gel battery with an AGM but AGM‘s are so much more available, etc.
    My questions are: 1) If i have to replace the whole bank – I am thinking AGM – am I right? 2) Do most charging devices have that Wet or AGM/Gel switch on them?
    Thanks Again….steve

    Reply  •  Rated article 5  •  April 9, 2012 at 6:29 pm
    • BatteryStuff Tech
      If you buy new batteries, AGM is a good option. Most chargers are pre-set for wet-cel and AGM charging voltages. If there is a Gel setting, there might be a switch. It‘s less common, but some chargers do have that option.

      Reply  •  April 10, 2012 at 10:11 am
  • Dave
    Good read. My charger has 2 battery type selections. 1-AGM & WET 2- GEL. I didn‘t know mine was a AGM it ended up being charged as a GEL. Now charger just reads fault and battery is at 7.8 volts
    Have I killed it?

    Reply  •  Rated article 5  •  March 17, 2012 at 7:55 pm
    • James Ville
      Charging an AGM with a Gel setting is not going to harm the battery. It‘s the other way around that is damaging. If the battery is reading 7.8 volts, that is very bad. Please to try recharge it correctly and promtply. Extreme discharge can lead to rapid formation of sulfation, which will shorten battery life. If the battery reads more then 6.5 volts, most automatic smart 12 volt chargers should be able to bring it back to charge. If the voltage does not reach 12 volts, there may be an short in a cell or two. If that‘s the case, the battery is useless.

      Reply  •  March 19, 2012 at 11:12 am
  • John Hall
    I am a long-term user of 12V batteries, having lived on a sailboat for almost 10 years. I concluded that gel cell btteries were the way to go for maximum life if discharged to the 50 % discharge point.

    Now I am much older and in an electric wheelchair, a Pride Jazzy. I have used both AGM and gel cells in my wheelchair, finding gel cells marginally superior in longevity, if recharged at 50% or less discharge point, with three stage chargers.

    1. Is there a difference between these two battery type in terms of longevity when properly maintained?

    2. If not, which battery type/chemistry is better for long life?


    Reply  •  Rated article 3  •  March 17, 2012 at 1:51 pm
    • James Ville
      span class="caps">AGMs and Gels both have the potential for many years of life, equally, if maintained properly. What you are doing now is good practice. ONe primary difference between the two is this. If you deeply discharged the battery (below 50%), the AGM would be damaged more than the Gel. Both will have their lifespan negatively effected by the event, but the severeity of the effect will be less for the Gel.

      Reply  •  March 19, 2012 at 11:09 am
  • Ken
    Exactly what I was looking for! Thanks.

    Reply  •  March 4, 2012 at 8:12 pm
  • Nevadahalfrack
    Finally!! A no nonsense simple and unbiased explanation of the two different oft confused power sources.
    Thank you.

    Reply  •  Rated article 5  •  February 18, 2012 at 3:59 am
  • Sunil Bhatnagar
    The fact that Gel batteries are more superior to AGM is not promoted in right way as AGM has many far superior working qualities which Gel can not offer. AGM batteries are fast recharge batteries and are availble easily worldwide. Gel batteries have very small market share. Cost per cycle is approximately same when AGM is compared to Gel.

    Reply  •  Rated article 2  •  February 7, 2012 at 4:12 am