Ni-Mh Battrey Pack charging Problem..Help??
 

recently i bought a HBX massive 1/10th scale truggy to yous out and about while im not at home with my 1/5th scale Baja since its to big to take with me everywhere. of which i bought about 4 months ago..

But i seem to have a slight problem with my battery pack for my Massive..After about i would say 3 uses of the pack it has suddenly started charging to fast and dying to quickly..

Its a 3600mah Ni-mh pack at 7.2v and when i put it on the charger i set it to charge at 3.6amps, and here is where the problem starts...My charger tells me how much capacity has been restored while charging and also automatically stops charging when the pack is full..But for some reason the charger says fully charged after only putting in 460-500mah back in to the pack..Im certain the pack is dead before i charge it and im sure theres nothing wrong with the truggy as i tested the pack on 3 of my friends trucks aswell and same issue as me the pack would just die at around 1min of use...which tells me the charger is only pumping in 400-500mah and just stopping. i have also replaced the charger just to make sure but still same problem as before, i also bought a second pack exactly the same but a different brand and same issue it just developed this problem after 2-3 uses.

So are there any specific settings i should set on the charger to make sure im charging the pack's properly??? any ideas whats happening or what im doing wrong??? Im still very new to this RC thing as i still barely understand how to run my baja as well as use my charger so help would be appreciated

Thanks =)

How warm is the pack getting at end of charge? Nimh should be noticeably warm, if not you are likely experiencing a "false peak". Restart the charger.

Also check each of the six cells for temp, if one is much hotter than the others it could be a bad cell.

Some chargers have a lockout feature to prevent premature shut off in the first few minutes. What charger do you have?

Welcome to the forum.

Dave covered most of what you need to know but there is something else to consider.

Those NiMH tend to self discharge just sitting which can cause them to get out of balance. You may have a couple cells that are totally dead while a couple others are nearly full which causes peak chargers to cut off. About the only things you can do about it are slowly trickle charge them overnight or discharge the cells individually to a common voltage before charging them.

Or just convert to LiFe or LiPo and eliminate all the headaches. :D

Question about nimh's.
I have some aa's I use around the house. I have a battery holder that holds 4 of them and that's how I charge them. I'm sure they are not "balanced" with each other. What if I hooked them to a bulb and dis charged them completely? Would that kill em? Or should I just charge them 1 at a time?

Most home AA chargers are not peak chargers, it's just trickle charging them so balance doesn't matter.

Basically when a NiCd or NimH get's fully charged, it can't hold any more juice so the excess turns to heat. This is why a fast charger needs to shut off because the cell will just get hotter and hotter until the thing explodes. With a slow trickle, the heat is able to dissipate easily so things don't go boom.

Now if you are fast charging them with a peak charger using a 4 in series holder, yes you might want to find someway to get them close before charging them. If you don't charge them until all four have gone dead in whatever device you use them in, then they are probably close enough for a below 1c charge.

At the end of the charge it is still Cold/Not even warm so im sure im not feeding the pack to many Amps at any given time,

I was researching that "False peak" thing and many people said to just keep restarting the charge until the pack is warm enough, which means its almost charged up im guessing?

Also my charger is a "UltimaXpro AHC-6AC" i honestly have no idea who made this thing or what, i got it from some discount hobby warehouse.

Thanks for giving me a straight clear answer =) compared to the guys on Hobbyking that are a bit rude and off the point.

Thx il try this out if all else fails =)

Also im planning on buying a HPI Savage Flux soon because My neighbour and some friends Built a track outback to small for my Baja so i need something Fast and small hahaha. Il be getting to two 4000mah Li-po's with that beauty so problem solved haha =)

Yeah if the pack isn't at least a little warm at cut-off, hit it again. False peaks are common with unmatched, unbalanced stick packs.

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Vote for Lipo all you want but help the guy with his issue first.;)

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NIMH packs..a bad cell can be found by either being hotter than the rest in the pack OR colder. I've had bad cells do both.

except for packs swelling, catching fire, burning the house down, probably going to need a new charger as well, etc.

Despite all that, they are still MUCH better and MUCH less hassle than NimH but saying there are no issues just isn't true.

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[QUOTE=wingracer;12344263]Yeah if the pack isn't at least a little warm at cut-off, hit it again. False peaks are common with unmatched, unbalanced stick packs.[/QUOTE

Thanks i decided to just keep restarting the charge until the pack was full like u said...did that for 2-3 uses and now it charges normally =D