rjs_13203

iTrader: (5)

can u charge a nimh 4200 battery at more then 4.2 amps, like say 6 amps? will it hurt the battery, will it charge faster, will it hurt the battery?

sp8y

Hi I charge my LRP 4200 at 4.5 amps but sometimes I charge them at 5.0 amps for quickness, thay seem to be ok charging at 5.0 amps but I would not go any higher than 5.0 amps.
Joe

rockstar81

iTrader: (5)

I have had some (4200's) that say you can charge them at 6 amps, but I wouldn't really recommend it, may preform slightly better at the moment, but I am sure it will shorten the useful life of the packs.

rjs_13203

iTrader: (5)

so 4.2 amps is what i should charge at. what about cycling them whats that all about

RocketRob40

The thing is that charging any battery at too high a rate, while sometimes giving marginal short-term performance gains, cut the long-term life of batteries.

And thus, and as so many battery companies recommend, I follow a simple formula - 1 Amp of charging rate per 1000 mAh of pack capacity MAX. So by following that a 1600mAh pack should be charged at no more than 1.6A, a 3300mAh pack at no more than 3.3A, and your 4200s at no more than 4.2A.

You can go higher, though it really cuts charge time only marginally, but doing so at your own risk - it all depends on how long you'd like your packs to last.

TeckLancer

iTrader: (16)

u can charge at 6. i charge all mine at 6 and i have had them for over a year some even 2 and they still work and charge great. i do equilize after every run and that helps

rocket-mtrsprts

iTrader: (1)

You can charge at all sorts of rates, but at the risk of over-hammering your packs which leads to shorter life. Equalizing or balancing helps prolong life, but most average users don't have the equipment.
Using the 1C formula is best ~ or as someone else said "1 Amp of charging rate per 1000 mAh of pack capacity MAX. So by following that a 1600mAh pack should be charged at no more than 1.6A, a 3300mAh pack at no more than 3.3A, and your 4200s at no more than 4.2A."

That's the smart way of doing it.

JeromeK99

iTrader: (3)

Everybody talks about 1amp per every 1000mah.. well.. that's an ok rule to follow. A safe rule.. no harm can be done.. In the old days with NiCads the higher the amp the better initial performance you got out of the back.. More kick at the start of the race.. so some people think that is true for the battery packs we use today.. well.. they are wrong..

NiMh battery are much different. they do not have a "memory" like NiCads.. and contrary to popular belief... they can be used many times in the same day. They only main concern is to not over-heat them. This will cause a loss in performance and possible damage the cells. Between runs, make sure you cool them down before charging them. I also like to fully "cycle" them down to 5.4v/pack (.9v/cell). I discharge them fully on a 20amp load (10 bulb discharger) and then on my Novak smart tray. Now you don't have to really do the discharge part.. but it makes it a lot easier to see how the packs are doing and makes it consistent for charging times. I know if a pack has false peaked if it doesn't take 45-50min @ 5 amps.

So... 5 amps in my experience is the proper rate. 4 amps is fine.. but you will be spending well over an hour between charges....


Jerome

not home

iTrader: (23)

i charge a gp 3300 at 6 amps.

rocket-mtrsprts

iTrader: (1)

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Morbo

Can anyone confirm this?

rocket-mtrsprts

iTrader: (1)

everyone can

Morbo

You can charge nimh many times in the same day? Can anyone other than rocket-mtrsprts confirm that?

Joel Lagace

iTrader: (4)

Yes confirmed..


Typical race day proceedure for a pack to be run twice that day:
-equilize each cell on smart tray
-charge at 6amps(dont matter if its 3300s or 4800s)
-Run pack
-discharge pack
-equilize on tray again
-when cool start over and race it again,

Most race days or nights dont give u enough time to run a pack more then 2 times so its not hard on them. And i have noticed the second runs to be punchier!

Loop&Roll

NiMH do have memory though, just not a pronounced as NiCd, they can also
be safely run more than once per day. Having said that I wouldn't discharge
or equalise them after the first run just let them cool and charge again.