Comments on: Proper Care and Feeding: NiMH Battery FAQs

By: Dave

Dave — Mon, 19 Feb 2024 13:33:50 -0800

Long term Storage of NIMH rechargeable AAA batteries question. You said to store NIMH batteries at 40% SOC. How do you know when the battery is at 40% SOC?

By: Sam-y

Sam-y — Mon, 26 Jun 2023 12:13:13 -0700

Very helpful!!! Thank you.

By: Phil Purnell-Webb

Phil Purnell-Webb — Wed, 28 Dec 2022 00:05:32 -0800

My solar lights use NiMh 1.2v 600mAh batteries. Can I replace them with (say) 2300mAh ones?

By: Sher

Sher — Wed, 29 Jun 2022 17:09:37 -0700

Hi. I have a sonic toothbrush with NiMH battery. I fully charged it, thinking my old sonic wasn't usable. I got the old one working and might not need the new one for a while. Will it damage battery to not use the now-charged new one for maybe a year?

By: Talia K

Talia K — Mon, 18 Oct 2021 15:11:50 -0700

I have a Philips XL430 cordless phone. Unfortunately I cannot use its NIMH 550 mAh batteries anymore as I have damaged one of them. I have replaced them by two fully charged GP 930 mAh batteries, however the phone does not charge and the screen says 'no battery'. What can be the reason? Thanks in advance.

By: Talia K

Talia K — Mon, 18 Oct 2021 13:08:16 -0700

Answered all my questions and more. Thanks!

By: Ronald Johnson

Ronald Johnson — Mon, 27 Sep 2021 12:32:20 -0700

Can I put these batteries in outdoor solar charged devices

By: Denise Meier

Denise Meier — Sat, 09 May 2020 10:58:51 -0700

can solar powered batteries be put in rechargeable battery chargers

By: Armand Boisvert

Armand Boisvert — Thu, 26 Mar 2020 08:26:45 -0700

I have NIMH batteries that came with my portable phones in 2017 the phone is acting very static breaking up how do I know when it’s time to buy new NIMH batteries

By: Jim

Jim — Fri, 24 Jun 2016 19:55:13 -0700

The article says i may need to cycle the batteries a few times to get peak charge but it also states not to fully discharge the batteries. How far should they drain before I recharge them to achieve a proper “cycle” to help structure the batteries?

By: Stark

Stark — Thu, 26 May 2016 01:18:44 -0700

Hello I have a remote controlled heli opterbut it seems it has a battery problem it does not charge so one day I removed battery and connected it with dry cell it underperformed but worked,the battery which I removed from helicopter was a small 3.7 v 85 mah rechargeable battery so the question is now which battery do I use in order to replace the helicopter battery and bring back to working plz tell me reply fast

By: William McCollin

William McCollin — Fri, 20 May 2016 14:50:23 -0700

Good info all through the questions

By: AL

AL — Sun, 28 Dec 2014 09:25:11 -0800

Excellent information. Thank you.

By: Chandrasekhar

Chandrasekhar — Tue, 23 Dec 2014 07:03:57 -0800

Tons of info..Excellent, Excellent & Excellent notes verrry useful

By: nona ebol

nona ebol — Mon, 08 Dec 2014 04:34:10 -0800

i bought this digital power charger w/ 4 pcs 600mah rechargeable batteries.. i tried to charge it but its too hot, both charger and the batteries, am afraid it will blast so i remove the charger.. is it ok if its too hot? and can i use the rechargeable batteries to solar garden lights?

thanks and more power!

By: Wayne

Wayne — Thu, 04 Dec 2014 12:23:22 -0800

I would like to know if I replace my current cordless phone battery with a higher capacity rechargeable battery.
For example, currently the battery that comes with the phone is using a 450mah capacity battery. Can I use a 1000mah or even a 2100mah rechargeable battery ? If its possible, does that means that the charging will takes a longer time and the usage time will be longer too ?

By: Manu

Manu — Fri, 14 Nov 2014 15:42:04 -0800

Hi, thanks for the article. Can you tell me what happens when you use a rechargeable Ni-mh 2100 with a normal AA battery? Did I damage the Ni-mh? Thanks!

By: Shannon

Shannon — Tue, 11 Nov 2014 08:13:13 -0800

You do not list cordless phones among the electronic devices that use these rechargeable batteries. I have a Panasonic cordless phone that takes Ni-MH 1.2v AAA batteries. Will any rechargeable Ni-MH AAA work in my phone?

By: MedicalGenius

MedicalGenius — Thu, 30 Oct 2014 07:41:30 -0700

Interesting article.

Question: If an EKG machine with an NiMH battery were to be unused for six weeks, what action(s) should one take to prevent premature wear of the accessory? Should the equipment remain plugged in, keeping the battery’s charge at full capacity?

Also, what is minimum temperature and/or humidity levels it is safe to store NiMH batteries?

Thank you.

By: SpongBob

SpongBob — Tue, 28 Oct 2014 12:04:42 -0700

Question: What temperature and humidity range can a NIMH be safely stored in? We have three EKG machines located in trailers. We would like to lower the temperature within those structures since they won’t be occupied for six weeks. How best can we conserve energy and ensure that the batteries inside the EKG machines aren’t harmed? Should the batteries simply be removed? The units are kept plugged in 24/7.

Thank you.

By: Ambrish

Ambrish — Tue, 28 Oct 2014 09:10:23 -0700

Can I use a battery with higher mAh than originally provided with my camera ? Will the same charger work for new battery as well ?

By: AVG

AVG — Tue, 14 Oct 2014 07:00:11 -0700

I have just received a new phone battery. Based on other purchase experience When I put it in the phone I know it will contain some charge already. Is it best to charge it fully straight away? or let it run down and then fully charge? thanks

By: Tep

Tep — Mon, 13 Oct 2014 14:59:08 -0700

Really like the article! I do have a question about batteries though: I have a device which is running on two AA Duracell batteries. The batteries (brand new) together is producing 3.2 volts (1.62 volts individually), which is estimated to run for at least 2 years. The device is constantly running and consumes about 300 Micro amps, which is not a lot. I was wondering, when might the batteries voltage begin to drop from 3.2 volts to 3.0 volts or lower? After constantly being used for a month straight, will it then begin to drop?

By: ROZ

ROZ — Thu, 09 Oct 2014 22:19:17 -0700

I have a Duracell GoEasy charger (a few years old now) that came with AA NiMH batteries marked with 1700mAh and see newer AA NiMH batteries with 2400mAh. Can I use the newer 2400mAh AA batteries in this charger?

By: Maggie

Maggie — Tue, 07 Oct 2014 07:13:57 -0700

Hi there… I replaced my solar garden batteries with new ones , because the old ones would not charge out side in the sun light anymore . ( I Use them in in strings of 50 small bulb fairy garden lights ) I ordered exactly the same batteries that were used in the solar panel for the lights, and they arrived uncharged. My problem is, that although I have put them in a battery charger several times to fully charge, they do not hold their charge for long, and the lights will not work for more than a couple of nights. The bright sunlight does not seem to power them up again during the day light. I have to keep taking them out of the panel to recharge every two to three days which is very annoying as the old batteries gave the lights life for about a year before they died. Any ideas what I am doing wrong ? Thank you so much … Maggie :)

By: Wanda

Wanda — Wed, 20 Aug 2014 10:39:40 -0700

Can NiMh batteries be replaced with alkaline batteries? Thanking you in advance.

By: K

Thu, 07 Aug 2014 23:59:40 -0700

how much longer does a 2300mah battery last compared to a 1700mah

By: Elsa

Elsa — Wed, 30 Jul 2014 10:19:23 -0700

I just read your article and the questions and comments. I think you may have answered my problem, but my specifics are a little different so I thought I would ask. I bought a new unopened box of Journey’s Edge Solar powered Outdoor lanterns from a yard sale vendor. The batteries seem to be in need of recharging. They are NiCd AA600mAh 1.2V. batteries.
I have some Energizer rechargeable AA 2500mAh 1.2 v batteries. I also have a Sanyo Ni Mh recharger. I am recharging the Ni Mh batteries now, but can I use these higher mAh batteries in my solar lights? Also should I try to recharge the Ni Cd 600 mAh ones that came with the lights in my Ni MH recharger? Will it harm the batteries or the recharger?

By: M Dawson

M Dawson — Mon, 07 Jul 2014 09:23:40 -0700

Hi ,I have purchased some batteries for my solar string lights Ni-MH AA 600mah 1.2 v but they have come uncharged. I found a cheapish charger at the weekend but the charge is considerably higher … 1200 mah if i remember rightly. Is it ok to buy ? Could i also recharge the original spent batteries…. Maybe I should not have bought new batteries first.. doh ! Please help…. Thankyou

Due to the fact that we don’t have all the information for your system we would need you to contact us at tech@batterystuff.com so that we can ask the appropriate questions, to get you the answer that you may need.

By: M Dawson

M Dawson — Sun, 06 Jul 2014 15:29:29 -0700

I have just purchased some AA Ni-Mh 1.2v 600mAh batteries to replace those used in my garden solar lights.Could i have just recharged the old ones instead of buying new ones? Also,can the new ones be charged in a charger used for 1200mah. Confused lol …Thankyou

By: Gary

Gary — Mon, 23 Jun 2014 09:31:50 -0700

Hi,
I’ve just purchased some AA 2400 MaH batteries for my solar lights. I’ve just noticed that the batteries that they are replacing are 600MaH. Will this make any difference to them working and also am I better off fully charging the batteries beforehand like you mentioned above (I think the answer is no to the seconfd question in this case !).
Please help,
Gary.

By: Tech

Tech — Mon, 16 Jun 2014 10:56:13 -0700

Always check with the manufacturer.

By: irfan

irfan — Wed, 11 Jun 2014 05:49:38 -0700

can i use 3000mah battery instead of 2000mah battery(recomd.) in my micromax canvas 2 colors A120 because it is causing heating problems and has low battery life… will dis change affect my phone ?

By: alan

alan — Fri, 06 Jun 2014 14:39:10 -0700

Great article, interesting read!
Could you help with my question? I have just bought a second hand a snap on diagnostic scanner that has an 8.4v NI-MH rechargeable battery that doesn’t hold its charge; I am going to replace this battery. The scanner comes with its own built in trickle charger and a separate battery only trickle charger both of which share the same power lead adapter. I noticed that this power lead adapter was not a snap on original but a Stontronics VE50-1500. The specs of the trickle charger require 14-16v dc input at 36W but the output of the Stontronics is +15v dc 3.4A at 50W, would this be overcharging the battery and could this be why the battery does not hold its charge? Thanks.

By: Doug

Doug — Thu, 05 Jun 2014 07:29:57 -0700

Is there a measurement for which I could use a multi-meter to determine if a NI-MH battery is still above 50% capacity/life? I have some that haven’t been charged that much and different chargers indicate they are fully charged, but they are clearly not when I place them in a digital camera or other higher current devices.

By: Lee

Lee — Thu, 05 Jun 2014 07:24:01 -0700

I use a set of wireless headphones 900 mhz . They came with 550 Ma NiMh and they work fine. When I switch to New Duracell 800 Ma NiMh the headphones have a popping sound. Switch back to orig. AAA and all is fine again. Any ideas?

By: Simon

Simon — Tue, 03 Jun 2014 14:09:55 -0700

I have a 9.6v nimh 800 mah battery pack for a Tonka toy truck. I’m looking to buy a smart charger for it but some of them are saying only use on 1500 mah or higher. If it’s a smart charger, will it hurt an 800 mah battery? If I buy a charger that comes with a new 2000 mah battery pack, will that somehow hurt the toy truck? If I’m understanding the article and comments correctly, it sounds like 9.6v is what matters and the higher mah will just take longer to charge and last longer. Am I right?

By: BArBF

BArBF — Thu, 22 May 2014 11:19:57 -0700

I got 15 solar pathlights and 12 of the batteries in them would not charge. They are located in bright bright sunlight. label says AAA rechargeable battery can be replaced with up to 900 maH. The original maH is 150. These were cheapos but nice looking bulbs. For the ones that DO work, what advantage would there be to replace with the 900 maH?
And would charging under indoor light be sort of the same as cycling the batteries on a charger? Can you OVERcharge these batteries that way? (duh here) lol

THanks so much!

By: Al

Al — Tue, 13 May 2014 09:46:18 -0700

Can you leave a Ni-MH battery on the charger indefinitely without damage – i.e. we have a small cordless vcaccum with a Ni-MH batter and a A/C plug in charger, and it says to toally dischargfe before re-charging – thedn requires 16 hours to recharge – making it troublesome if it runs down during use. If I forget to unplug it will damage occur – or if I just leave it plugged in will it overcharge/damage the battery? Help!!

By: samer

samer — Thu, 24 Apr 2014 17:53:50 -0700

an awesome article thanks man but i have a question ……..
if a have a battery 5 v / 1 mah can i charge it with a 5 v / 1.5 mah charger or a power bank ?

By: JIm H.

JIm H. — Tue, 22 Apr 2014 16:14:34 -0700

Question: Do Ni-MH batteries lose power – amperage (like a car battery would)? In other words, the voltage is 2.4V, the appliance (beeper) lights up but doesn’t vibrate.

By: Effem

Effem — Sun, 30 Mar 2014 00:08:38 -0700

Is it safe to use Ni-Cd battery charger to charge Ni-mh batteries? What are the precautions if I will do this? Another question: Can I charge different brands of AA Ni-mh batteries at one time in a 4-slots battery charger?

By: Vladan

Vladan — Wed, 26 Mar 2014 08:18:18 -0700

Wow! Very helpful, thank You!!!

By: Steve

Steve — Fri, 21 Mar 2014 16:23:23 -0700

I have a radio that uses 4 AA batteries. When I put alkaline or NiCad batteries in it works fine. I recently purchased NiMH batteries to use in it and charged them up. My multimeter says they have almost 1.35 volts each and the amperage measures higher than the NiCad batteries — but when I install the NiMH batteries, the radio doesn’t show anything, no clock, no battery level, nothing. It looks like there are no batteries in in at all. When I put the NiCad batteries with lower voltage and amperage readings back in it fires right up. Any thoughts as to why?

By: Kurt

Kurt — Sun, 16 Feb 2014 11:47:50 -0800

So I wonder if someone can help. I have a communicator for a helmet that runs on a NI-MH battery. The battery pack says 4.8v 1000mah. The charger that came with the unit is a 12V 300ma charger. I also have one from a small cordless drill that is 12V 200ma. Is it better to charge is with the 200ma? Just curious if that is a slower charge and if so it is a better way to go for longevity of the battery? Thanks!

By: Jim O

Jim O — Fri, 29 Nov 2013 15:34:13 -0800

I have a Cobra two-way radio set. It came with SANIK NiMH batteries, 1200mAH. When the radios are placed in the charger, the LEDs light up and they seem to charge and all is well. When one of the batteries went bad, I replaced them with LENMAR R2G NiMH bateries, 1.2 volt but with a 2150 mAH rating. They don’t seem to charge, and the LED indicator doesn’t come on. The charger instructions say you can leave the radios on the charger even after the battery is charged.

So, is there some reason the longer life batteries won’t charge? Am I stuck with only the shorter life batteries (which I can’t seem to find)?

Thanks.

By: R Woods

R Woods — Wed, 14 Aug 2013 16:34:20 -0700

Outstanding site. Exactly what I was looking for and the information on more modern batteries was very interesting. Guess I‘ll have to check out your home web site. Thanks, r woods

By: JT

JT — Fri, 09 Aug 2013 09:59:16 -0700

Great write-up. Much more clear and concise, and with a more user friendly presentation than most articles I have read (although they were intended for a different audience).

QUESTION: At what percentage of the rated capacity should Ni-Mh and Ni-Cad batteries be replaced?

Example: An 1800mAh Ni-Mh battery is now cycling (discharge / charge with a microprocessor controlled charger) with a full charge at 1200mAh. Thus, the battery is now at 67% of its’ rated capacity. How do you decide if it needs to be replaced? (These numbers are just an example, not representative of my actual batteries). If it matters, they are used in High-end 2 way radios.

By: ashton grave

ashton grave — Tue, 06 Aug 2013 22:52:48 -0700

very comprehensive & useful article. I have replaced nicad 1.2v AA batteries in a solar sensor light with great results. whatever the nature of the cheap solar panel charging current etc is, it seems to work fine.

By: Fast Robert

Fast Robert — Thu, 25 Jul 2013 22:50:05 -0700

Really clear & helpful

By: adel salem

adel salem — Sat, 22 Jun 2013 07:49:45 -0700

thaaaaanks

By: daveboy

daveboy — Fri, 21 Jun 2013 03:50:41 -0700

I was confused regarding rechargeable AA batteries,I have been using NI-CAM with poor results,I have now
changed to NI-mh,hopefully the dreaded \\\“Memory syndrone\\\” is a thing of the past.

Super article Tank you

By: Autumn

Autumn — Thu, 30 May 2013 14:47:50 -0700

I just wanted to let you know that this article was extremely helpful and useful. I now have the answer I need to make my battery purchase. Thank You!

By: chuck

chuck — Thu, 30 May 2013 13:13:13 -0700

I have a rayovac rechargeable alkaline labeled 1.5v. are they still available?
Thanks for the help

By: AbhinayD

AbhinayD — Tue, 21 May 2013 05:36:33 -0700

Kodak Ni-MH Rechargeable Battery heat up while charging..is it a problem..plzz help

By: shaz

shaz — Tue, 21 May 2013 01:14:32 -0700

i have 2 nimh 1.2v rechargable batteries. I got a 11v battery charger from old stuff…can i use it to charge my battery..? Or how much volt will need to charge that batteries? I like to build circuits.. can i modify my charger?

By: Dick

Dick — Sat, 20 Apr 2013 11:37:10 -0700

This was a great article. When I first used solar lights in the yard and the batteries eventually failed I could not find 400maH ones anywhere. I succeeded in locating 1000maH by mail order from China. I always worried that the difference in spec would be a problem but I could not find any information on the Web about it then. Yours is the only article that discussed the point, and I‘m glad to find out that difference in specs is not a problem.

By: Betty

Betty — Thu, 14 Mar 2013 06:48:35 -0700

Great tech support here!

By: chohan

chohan — Sat, 23 Feb 2013 03:27:43 -0800

i have got 3 x makita 18v 2.6ah nimh batteries

now the problem is these batteries show full charge on multimeter and they hold that full charge as if you see after 10 days of charging the batteries will show full charge on multimeter…..the batteries give good spin to the drill but if i apply pressure with my hands i can stop the drill

why is this???

remember the good 18v batteries you cant stop the drill with your hands

so why they not performing well under LOAD

answer will be much appreciated

thanks

By: Dmac

Dmac — Mon, 18 Feb 2013 22:21:04 -0800

Hi, I bought a digital camera and the sales guy told me to charge my Kodak Ni-MH batteries for 4 hours before use, I charges for 6 hrs. I assumed I should charge for 4 hrs every time but the battery manual recommends 11.5 hrs. Should I listen to the sales guy or charge as per the manual. Or does anyone know how long I should charge my batteries?

By: Gabe

Gabe — Mon, 18 Feb 2013 18:40:34 -0800

It didn‘t dawn on me to look into the details of my AAA batteries and I‘m wondering if I may have screwed up an antique device of mine.
Device requirements: AAA alkaline batteries (It‘s an old device – a well-preserved Handspring.)
What I put in there: NiMH AAA batteries (Eneloop)

What happens in cases like these?
Many thanks.

By: julia

julia — Thu, 07 Feb 2013 07:21:14 -0800

Hi,
I want to buy an adapter for my car since it is too old to have the place to be able to plug in and listen to my Ipod. I always heard that just a plane invertor is too high a voltage. If I get a 2100 amh charger, will I be able to play my Ipod off of it without damage? Same for a cell phone?

Thanks!

By: bruce

bruce — Tue, 08 Jan 2013 19:26:20 -0800

I just got a OFNA Receiver Pack 110V AC NiMH Wall Charger 10214. It is rated at 6v output, but is showing 11.48v on a meter at the connector. Is this usual to this type charger? It is specifically for NiMH charging on the label, so maybe the circuitry turns up the voltage at initial hookup? I just bought this to charge a 4 pack of 2000ma AA size batteries. The charger is very warm to the touch with a red charging LED showing. No instructions came with it.

By: Matt

Matt — Sun, 06 Jan 2013 15:25:30 -0800

Great article. My question … our video baby monitor came with three 1.2V 2000 mAh NiMH batteries in the handheld monitor. We charge them using the supplied cable that just plugs into the handheld monitor. The batteries that came with the monitor are slowly dying so I would like to replace them. Will any brand of AA NiMH battery from a local store do the trick?

By: Chris

Chris — Tue, 18 Dec 2012 11:38:54 -0800

I have a Kodak digital camera (Easy Share Max Z990) that came with 4 rechargeable 1.2 volt NiMH AA batteries and a charger. Is it safe to use 4 alkaline 1.5 volt AA batteries instead?

By: Steven

Steven — Sun, 09 Dec 2012 10:09:23 -0800

Very useful info – thanks. I bought a set of store brand 2450mAh AAs which I have been charging with an Energizer CHDC7. Strangely, two of the batteries now give the “bad” blinking indicator. Two seem fine. Is it common to have very different performance within a group bought in the same package?
Also, I doubt I have charged them even 75 times, after mostly using them in digital cameras,(Over a two year period). Is there any justification to complain to the retailer?
Thanks!

By: Beatlearl

Beatlearl — Sat, 08 Dec 2012 12:26:57 -0800

I had to bookmark this site because I know smart when I see smart and after reading some of the articles on your site you guys are smart.

By: BOB

BOB — Sat, 24 Nov 2012 21:53:09 -0800

I have a question regarding this paragraph:

“When I receive my batteries do I need to charge them?
Yes, before you use your new NiMH batteries for the first time you need to charge them fully. Please note that for new NiMH batteries, it is often necessary to cycle them at least three to five times or more before they reach peak performance and capacity. The first several times that you use your NiMH batteries you may find that they run down (discharge) quickly during use. Don’t worry, this is normal until the batteries actually structure internally.”

I purchased an electronic item with a NiMH battery and mistakenly didn‘t charge it as long as the manual said (it said up to 16 hours and I did it about 2 hours). After using it and wondering why the battery was already low, I looking in the manual and am now charging it fully. Since I didn’‘t fully charge it before first use, will that cause a problem for the battery?

Thank you.

By: Mani

Mani — Fri, 02 Nov 2012 20:41:15 -0700

Nice and useful information. thanks for sharing.

By: Siddharth

Siddharth — Thu, 18 Oct 2012 01:39:33 -0700

For how much time do i have to keep my 2100mAh NiMH batteries in charging???
My charger doesn‘t have any indicator for the batteries, if they have fully charged….Plz Help me with the exact time!!!

By: amin

amin — Wed, 17 Oct 2012 11:11:13 -0700

Which is the best battery 1000mAh or 2100mAh ? i use sony BCG-34HW2RN battery charger. Can i charge 2100mAh battery in this charger ? please reply
Thanks

By: Manoj A

Manoj A — Tue, 16 Oct 2012 07:49:26 -0700

I am having CB-5AH NI-MH canon charger. Can i charge my batteries rated for 1000mA NI-MH. Thanks in advance. I would like to thanks you for giving wonderful understanding.

By: DSANJIB

DSANJIB — Sat, 13 Oct 2012 08:28:44 -0700

AM USING KODAK DIGITAL CAMERA BATTERY OF 2000MAH AA 1.2V.HOW MUCH TIME DO I NEED TO RECHARGE THEM?

By: Rajesh

Rajesh — Tue, 09 Oct 2012 00:52:37 -0700

Can I use a charge for any battery capacity (say 400mAH to 2800mAH)? Or chargers are designed to use specific capacity?

E.g. Can I use “Sony BCG-34HWN Battery Charger” for various NiMH batteries (say 400mAH to 2800mAH)?

By: Ketan

Ketan — Tue, 25 Sep 2012 12:40:10 -0700

OK – my question: How many Watt-Hours can I squeeze out of a standard 450mAH 1.2V NiMH battery? Ineed to calculate scenarios, such as drive a 1 watt load for certain number of minutes etc.

By: Vicki

Vicki — Sat, 04 Aug 2012 12:07:28 -0700

Wow! This is very helpful and interesting info. I didn‘t realize there were certain devices where NiMH batteries should not be used, nor did I know the difference between charger types. Thank you for taking the time to educate us about these things. Warmly, Vicki