NIMH Charging.. When is it to many amps?

[NORCAL SS]

2000mah 7.2v nimh battery and seeing all this info on the net

Some people say 2000 mah you can charge at 2 amps while others say only .5??? I dont want to wait here for 15 hours for the pack to charge but at the same time I dont want to screw the cells up so whats a good compromise.

Promatch racing says to charge their cells from 4-6amps so just seeing if this applies to my nimh also?

i have a thunder ac6 charger

 

[JohnRobHolmes]

What is the cell size/ shape? I say keep the cells under 140f for longevity. The cooler the better. 2a should be fine, but .5a would be a good compromise for giving your packs a very long service life.

 

[Chris_The_Battery_Man]

2 amps is most as I would go

 

[EddieO]

The lower the better in theory.....we used to charge are racing packs at 6+ all the time....

2 amps will take a while.....promatch knows batteries well.....I think 4-6 is just fine. Like John says, monitor the temp......

Later EddieO

 

[Chris_The_Battery_Man]

4-6, unless it is a NiCad, is a little harsh. The pack will get really hot, plus it will have the tendency to false peak.

 

[2500hdon37s]

id stay 2 and under. or just make the switch to lipo like i finaly did, so much better!

 

[Manning]

Depends. If they are super cheap cells, you may only be able to charge at 1.5 amps. If they are killer cells with super low internal resistance, you might be able to go 5 amps.

If the batteries are getting hot quickly during a charge, you are charging at too high a rate. All batteries are different, and as the get older the max charge rate goes down due to the internal resistance going up.

You want a Ni battery to be done charging at about 120F. Generally that's pretty warm in your hand, but you can hold on to it tightly with out it being uncomfortable.

 

[Maxx_Savage]

Lower is always better.

I never go over 1C and normally stick to 1/4C or 1/5C.

Even at 1/2A, your 2ah pack is still only going to take around 4h, not 15h, LOL

BTW, you didn't say whether you actually have Promatch cells, so be very careful using their advice.

 

[Banditt]

Charge @ 5 amps. We've charged those cells for almost 15 years @ 5 amps. Life expectancy does go down a little. Just make sure they are slightly above room temp when the charge is finished and not scorching hot. You will end up getting new batteries before actually wearing them out. Even if you do they are only 2000mah and not worth much.

 

[JohnRobHolmes]

Depends on what "those cells" are. If they are 4/5A he will kill them quick. If they are subC he can pump the amps.

 

[team3six]

Not trying to hijack the thread. But I think its very cool that all you electronics vendors are cool among eachother. not something you see everyday from vendors in the same class. "thumbsup""thumbsup""thumbsup"

 

[fred0000]

I charge at 2 amps, i have a 2600mah and a 4500mah, it does take a while, but I dont want to go faster to help with life of the pack, if i'm going crawlin the next day and wont have a chance to re-peak my packs, I peak them at .5 amps the day before, just my routine I guess, works for me.

I charge in the evenings or when i'm workin on my crawlers, then when its time to go crawl, I peak them again just to be sure. (as far as I know re-peaking is NOT an issue for ni-mh or li-po's aslong as your using a proper charger, you wouldnt want to do this with anything BUT a peak charger)

in addition, I charge my li-po's at 1C and always balance charge, batterys might not be overly expensive, but if you have to buy them often, they are, its not worth the chance for me. but if your smart about it and charge in the evenings or when your workin on your crawlers. re-peaking day of only takes a few min to do them all. $0.02 take it or leave it

 

[skinner]

om my good race packs (4200-4600 nimh ib's) side by side sub -c, I always did 5-6 amps.
now on smaller mah & cells I charge lower if pack can't handle temps.
but always repeak before day used which takes few minutes.
so if you wanna be safe do 2 amps.

 

[gymjunkie23]

What about my reedy wolf pack 3600 and 4200 nimh ? My Novak charger does 0.5-4 amps and up to 8cell..thanks

 

[Banditt]

Depends on what "those cells" are. If they are 4/5A he will kill them quick. If they are subC he can pump the amps.

Yeah I should have read and asked if they were sub C. If they are only the 4/5A then yeah charge at like 2 amps and you should be good to go.

 

[bob1961]

don't/shouldn't charge more then what there mah are....

1500 mah = 1.5A max
2000 mah = 2.0A
3300 mah = 3.3A

and so on for each mah number as max A charging "thumbsup" .........bob

....

 

[Charlie-III]

don't/shouldn't charge more then what there mah are....

1500 mah = 1.5A max
2000 mah = 2.0A
3300 mah = 3.3A

and so on for each mah number as max A charging "thumbsup" .........bob

....

This is also known as a "1C" charge rate."thumbsup"8)

 

[reden]

Lower is always better.

I never go over 1C and normally stick to 1/4C or 1/5C.

Even at 1/2A, your 2ah pack is still only going to take around 4h, not 15h, LOL

BTW, you didn't say whether you actually have Promatch cells, so be very careful using their advice.

I dont go over 0.5C(Graupner glider TX).

For most batteries 1/4 to 1/5 is a good compromise.

Its mostly about how much life do you want out of htose packs.

High charge - short life
Low charge longer life

I have also heard (hearsay) that fast charged batteries (NIMH) gives a better punch.

 

[Charlie-III]

I have also heard (hearsay) that fast charged batteries (NIMH) gives a better punch.

Normally I would charge NiCD or NiMH at about "1C" until "full". Just before I race, I would re-peak a couple of times to get some warmth into them since they perform better for the 1st minute or so.

There is a thread (just recently bumped up/added to) regarding temperature & battery performance.