Battery question

[ED66677]

hi all
something worries me...

I'm currently running a 8XL under 12 cells and I have 2 packs of 12 GP2200 in parallel, I noticed that when there's no load on the prop motor spins faster with 2 packs than one, sound logic!

But I see all around guys running big motors that drain lot of amps, 70, 80 or 100!
If I look at most of the best battery specs like GP's or IB's, max amps is 30 for GP's (from 2200 to 4600) and 40 for IB's 4200!
Do you guys have packs in parallel?... Or do you simply drain more that cell can provide?... but kill packs quickely?

Are 20C (may be 30C if there's any on the market?) Lipo's a real advantage? do they really provide 20C? A 4000 Lipo pack would then provide 80 Amps continuous for almost half weight!

[Fluid]

What NiMH Battery manufacturers recommend and what hobbiests do are two different things. Drawing over 50 amps from a NiMH cell does shorten its life, but you still get 50-100 cycles of good performance with most cells. Some cells are less robust, others will take it easily.

Yes, LiPo cells can have major advantages over NiMH cells. A 4000 mAh 20C pack can give out a continuous 80 amps - in theory. The sad reality is that many of the cheaper packs are over-rated by the sellers, and a 20C-rated pack may actually struggle to give up 12C. The only way to avoid these poor cells is to pay for good ones. No free lunch unfortunately.

LiPos have much less internal resistance than NiMH cells do, and for the same capacity they weigh about half as much. More voltage under load along with less weight means better performance for most boats. What many racers do is parallel packs, hooking them up to give the same voltage but twice the capacity. This either increases run time, or doubles the power (amps) you can pull out of them.


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[ED66677]

Ok so I'm good in the way I'm setup 2 packs of GP2200 is better than 1 of equivalent capacity (4400) :)
I'll stay with my Twin GP2200 on the next boat!

[Jeepers]

try a set of IB 4200s you"ll be glad you did!!!!! major performance difference.

[ED66677]

I will, everybody talks about IB's so I'm going to try soon, but I will also move to Lipo's soon, on maxamp.com, they seem to have good lipo's 4200 @ 20C constant and more, it weight only 400grams, this must change a lot compared to Nimh just because of the 600gram you save!!!

[Raydee]

Do a lot of research before you buy Lipo's. There are some very popular Lipo dealers that over rate their cells. I personally saved and finally bit the bullet for Poly RC cells and I am happy I spent the extra money.

[Mich. Maniac]

I have been using the VENOM line of lipo. granted they are somewhat new to the biz but they have been nothing but reliable and powerful. I am also using venom balance charger. takes a while to charge but 20 cycles and they hit the same numbers every time.