Shrekito

iTrader: (4)

Good morning all,
I bought a new 7.2 3600 NiMh battery yesterday. Now I haven't charged the battery yet. The guy at the L.H.S. told me that NiMh's don't have a memory. Should I charge the battery on 1A to give it a good deep charge. But then I wonder am I wasting my time? If the battery doesn't have a memory anyway. My peak charger can charge from 1A to 4A. Any input is always appreciated. Thanks

JeromeK99

iTrader: (3)

Go ahead and charge it at 4amps. It might take a couple of cycles to get it working up to speed.. What that means is it might take a couple of charges and discharges (runs) to get it to where it should be. They don't really have memory, but you should let them cool down after a run before charging it again. Now the other thing is that each cell is different, even if they are matched. Discharging and equalizing is a good idea. It also allows you to get a feel for how they charge and you can tell if something is wrong if the charge time or other reading on the charger differ from run to run. If it is run all the way down, it should take about an hour, probably a little more to charge it all the way up. My last set of 3600 would take 45min @5amps.

Jerome

Shrekito

iTrader: (4)

Okay cool I was going to charge it a 4A. But I though just to be on the safe side I will ask. Now as for discharging I usually just run the battery down till the car doesn't move. Is there a better way.

JeromeK99

iTrader: (3)

Running it down will work... but I've always used a discharger made from 10 tail light bulbs (GE1157). This is basically a 20amp draw, pretty much the same as a stock motor running at full speed. I hook them up to that until the light starts to fade a bit, not all the way down. Then I used a equalizing tray to bring each cell down so that when I charge them again, they are all the same. If a cell starts overcharging when you are charging up the pack, it is actually discharging and can make it very hot. This eventually harm the cells. Some chargers have a discharge feature.

NiMh can be a lot of work if you want the proformance.


Jerome

rctazmanmc

iTrader: (141)

I agree with JeromeK99 on a discharger and care.

I would avoid running it down until it does not move since most cells in a premade pack are not equal or "matched" so you could have a cell reverse on you and it is worthless on most parts then.

Let the packs cools also before charging them back up - heat is not a batteries friend for the most part.

Take care of them and they will last a long time. I have packs that are 2 years old that still perform well.

Also store the packs with about half the charge in them.

Shrekito

iTrader: (4)

Thanks for all the info guys. I charged the pack on Monday at 4A. Then yesterday I got home and peaked the pack. Wow what a diffrence going from my old 2400 NiCd packs to a 3600 NiMh pack. I can't even imagine what a lipo pack will do to my truck. I thought my motor was wore out and I needed a new one. I put that new pack in and the truck rips. I really want to thank everybody on the forums for all the info. It makes it so much easier to get into a new hobby when you have the information you need.