what is wrong with my packs?

[beason]

I finally got the parts to get my tc4 back on the road, and went to run it.

the packs i have are 6 cell nimh sticks at 3k mah.

It has been months since i messed with the car or the packs.

I put one on the charger at 3amps and started the charge. it peaked in less then 10 min, so i put it in the car and maybe got 3 min of run time before it stopped totally.

i tried again and it only took about 800mah before it peaked.

I set it up to discharge/charge at 1amp and it took 2800 before it peaked. I tried again at 1.5amp and it was about the same.

why will my packs not charge at 3 amps?

I'm getting frustrated with this stuff. I quit nitro because of all the extra maintenance, and now if i leave the electric stuff on the shelf for very long it craps out. what am i doing wrong?

 

[HPIguy]

Beason, sounds like we're in the same boat in a lot of ways. I quit nitro for the same reasons, then got some real eye openers about electrics, and specifically battery storage. From what I've read, a NiMh pack stored at room temperature will lose around 40% of it's charge per month, and eventually they will drop below their safe threshold of 1 - 1.1 v per cell and sustain permanent damage. From my reading the best long term solution is to pack them in ziploc or vacuum bags and store them in the freezer, where the self discharge issue is greatly reduced.

EDIT: Try cycling them a few times on the charger. I rescued a $50 lipo that I thought I had ruined this way.

 

[Metalhead Matt]

+1. Cycle them low rates. After 4-5 times, if they don't come back, it's time to grab some new ones.

 

[beason]

they charge fine at low rate 1 to 1.5 amps. its when i try to fast charge that i have issues. my venom has adjustable discharge up to 1 amp and that is what i have it set at. is this correct? I may try slowly moving the rate up to see where they mess up at, maybe i have a bad solder joint that wont take the juice.

when i slow charge them they run good, it just takes forever to charge at 1 amp.

should i try to cycle them at 3 amps? higher? I've heard to charge at 1 1000th of the max mah, so a 1500 pack at 1.5. a 2000 pack at 2, but to not charge over 3 amps. is this correct?

 

[Metalhead Matt]

I've heard and followed the same charging rates that you stated Beason, and have never had a problem. About the only thing I can think of is charge them slow and run them down a few times, then try upping the charge rate. If they're charging fine at 1 amp, and running fine in the car, they should be all good. Right?

 

[Lessen]

I'm with M&M on this one. I probably will need to do it as well the next time I want to run something. Cycle them like 5 times at 1A. I think it's important that the pack gets up to full capacity each cycle and if that means you have to do it at 1A then that might be what it takes. However, if it doesn't fully charge at 3A after all that cycling then it's time to replace it.