1 cell lipo pack = 4 cell NiMh?

[strodedawg]

my question is a 1s2p(?) the equivalent of a 4 cell nimh pack? i understand that the voltage would be slightly lower - lipo would peak around 4.2V and nimh at about 5.2v. assuming at least 15-20C and a capacity around (2x3200 cells) 6400mah would this be a capable racing battery for a 4 cell pan car. lastly do you think it could handle a mod bl motor?
thanks for the time

I think you'll want a smallish 2s LiPo.

[DrKnow65]

expect a lower voltage with a load applied (3.1~3.8v) so it's not much of a replacement for 5.2v

[strodedawg]

would a higher c rating offset the voltage loss?

[DrKnow65]

yes and no... higher C ratings tend to translate to lower internal resistance, but there are some 25c cells that hold their voltage better than 30c cells. No matter what you won't find a lipo cells that will stay at 4.2v even at 5c.

if weight is the issue, you can get a lower capacity with a higher C rating that should supply the amps you are looking for.

try to get a lipo that is 120% of the rating you need.

[strodedawg]

the problem is.... it is a 4 nimh cell 19t/10.5 pan car class and have a 2s lipo would be too high in voltage. is there a regulator to bring it down to 5v and handle the rigors of racing?

I had no problem with small 2s LiPo's in ratshack x-mods which run on 4AAA cells. I don't believe you will have a problem with a small 2s. Or is the voltage just too high to be within the rules for that class ? If that's the case, have you considered using 2s LiIon ?

J.

[strodedawg]

the voltage is the problem, not the batts. can you recommend a good 2s Liion and how do they compare to lipos?

[BrianG]

I would say 3 NiMH cells=1s lipo. 3 NiMH nominal = 1.2v and max = ~1.4v. Put three in series, that's 3.6v nom and ~4.2v max. A 1s lipo is 3.7v nominal and 4.2v max. But as others have said, the voltage drop of NiMH is higher so you'll need an extra cell or two to get the same nominal voltage under load.

[strodedawg]

would a 1s4p work? so the capacity of the battery would quadruple and the voltage drop would be lessened correct?

[Arct1k]

A123 2s2p? 6.6v?