Charging?
 

I’m relatively new to electric (& this forum). I was into nitro for several years and got an E-Maxx one day and loved it and now I can’t stand my nitro’s at all any more. I am in the process converting my entire fleet of nitro’s to electrics and selling off what I don’t want to convert. I have basic charging down but I would like to know the best way to charge NiMH and Li-po. I know that you don’t want to charge over one C for a Li-po but would this mean that you could charge an 8000mAh battery at 8 amps? That seams high to me. My LHS owner says he dose not charge any Li-po’s over 1 amp to be on the safe side. And what is the recommended charging rate for NiMH batteries too? The charger I use is a Duratrax ICE if that helps. Any and all information is appreciated.

Welcome to RC-Monster! Another one who has caught the electric bug!

When charging Lipos, the easiest way to determine the charge rate is to get the capacity, divide by 1000, then multiply by the manufacturer's recommended charge rating (the 'C' part - this is usually 1C, so stick with that to be on the safe side).

Example 1
Battery 8000mAh, max charge 1C
8000/1000 = 8
8 * 1 = 8A

Example 2
Battery 2500mAh, max charge 3C
2500/1000 = 2.5
2.5 * 3 = 7.5A

Nickel based batteries can be charged at about 2-3 C safely, but watch the temperatures the first few times, don't let them get too hot.

I don't have experience with that particular charger, but they all work using the same principles as above. Just make sure the charge settings are correct, and you should have no problems.

Thanks for the quick response. This was the information I was looking for. The Duratrax ICE I use has a temperature sensor so that shouldn’t be too much of a problem with watching the temps. Thanks again for the information.

also, are you using a balancer during charge?

Some people say you only need to balance every few runs, but i and i think most people here balance every charge.

Also, lipos should NEVER get warm/hot while charging. Its a clear way to know you got a problem

If lipos get hot while charging it may be too late...

I balance every charge, except at the track, when I need it charged before the next round, it takes about 5-10 minutes less.

With the temperature thing, he was talking about the NiMH batteries he has.

PS make sure you use the Lipo charging mode...

i know:yes: just pointing out hotlipo during charge= NOOOOOO

Thanks for all the responses. I also purchased a Blinky balancer for when I start charging li-po’s (Have any of you used this balancer before?). The first Li-po battery that I just recently purchased was a Dynamite 1900mAh 7.4v for my Mamba-25 powered Mini-T :intello: . I have put about two cycle’s trough it and there has been no sign of heat during charging probably because I charge it at one amp.

As for the temperature sensor on my charger, I can adjust the temperature cut-off so that when I charge li-po’s the slightest increase in temperature the charger will cut off. But I don’t think I should have too much of a problem with over charging li-po’s because I will be charging the lipos below one C.

I just want to double check, I could safely charge lets say an 8000mAh Li-po battery at a maximum of 8 amps (1 C)? I probably won’t charge that high but I just want to know that this is right. Thanks again.

I haven't used an actual Blinky, but the CommonSenseRC balancer is VERY close. Operation is simple; just hook it up to the balance connector.

Lipos should NEVER get hot when charging even at the full 1C, so you could charge at 1.9A and still have a cool pack. If you use a temp probe, it might false trip simply with changes in ambient air temperatures. No need for it IMO. As long as the pack is healthy and in balance by the end of the charge, there will be no heat buildup.

Yes, an 8000mAh battery can be charged at 8A with no adverse effects. You could charge at lower rates but that will only make charging take longer. The only reasons to charge lower than 1C are A) you are in no hurry and don't mind wasting time. :smile: and B) if the pack is quite a bit out of balance. A slower rate will ensure the balancer has a chance to fully balance before the end of charge.

Thanks for the response, and yes I have had a false temp trip because I had it set at 85* and that was about what it was outside. Good to hear that I can charge it a one C and it will be fine, just though that just because it says the maximum charging rate is one C that it was not recommended charging it at one C constantly.