LiPos and Amp Discharge - RC-Monster Forums

GeeReg · **LiPos and Amp Discharge -** 07.10.2006, 12:12 PM

I'm trying to get into lipos and I'm looking at the discharge rates. I'm trying to figure out what kind of rate I need and what is too little or too much. If I have a motor with a max amp rating of 69 say, what does that usually equate to for continuous discharge? I realize it depends on a lot of variables such as vehicle weight and terrain, but is there a general rule? What happens if the max discharge of the lipos is less? They will get hotter faster and easier and I lose performance correct? What should I be looking at for continuous discharge for my brushless MT (Feigao 380 6L) or something like a Novak SS+ 5800 in my T2?

I also might use them in a brushed setup and have no idea how much something like a stock 27t uses. I'm assuming it's pretty low.

Basically I'm wondering if/when I need to parallel the cells because I'd like to minimize the cost so if it's not needed I won't.

MetalMan · 07.10.2006, 05:53 PM

There isn't really a "guidline" per se, since there are so many factors. The best you can do is to be conservative and get a battery that can handle more than you think you would need.
When Lipos are pushed to their limit, they will get warmer, but also will cut out sooner (hitting 3v/cell, when a LVC is used, like it should always be).

My thoughts are that you should get a battery that can handle at least 50amps cont. for the T2/SS5800, and closer to 60amps cont. for the MT/6L. If you get one battery to share between them, then go for 60amps continuous. This way you'll be more on the safe side, which will increase the battery's life (compared to a battery used closer to its limit).

GeeReg · 07.10.2006, 07:56 PM

I see. I think I'm sticking with NiMh in the MT just because it's hard to fit a long pack in it due to the layout. I will probably pickup a 6000 2s2p for theT2 and something 3s2p or 4s2p for my Thunder King project I'm doing next. Is 3s enough for an 8lb truck? I looking for something quick but NOT crazy power because it can't take it. Maybe a 10L or something even milder on 3s?

MetalMan · 07.10.2006, 10:27 PM

A 9L should work with 3s on an 8lb. truck, since it's only 2wd. You have the right idea for the T2.

GeeReg · 07.10.2006, 10:48 PM

Ok thanks for the input. I'm trying to keep the cost down and 4s2p with a high continuous discharge is getting up there.

BrianG · 07.10.2006, 11:11 PM

Truerc.com has some high capacity 8Ah 10c packs for $135, but they are sold out right now. I've been eyeing the 5s2p packs for some time for $165...

http://home.comcast.net/~truerc/custompack.htm

The bottom few packs on the page...

MetalMan · 07.10.2006, 11:38 PM

Actually, True RC just got in their shipment of the cells. If you check out the "Loose Cells" section you will see that they are there. If you email True RC they should say that they can make up a pack for you.

BP-Revo · 07.11.2006, 02:23 AM

If you get maxamps lipo's (which are shorter than a 6 cell pack, but a bit taller), the 8000mah ones handle 128amps burst and 96 constant while the 12000mah ones hadnle 192 burst and 128 constant or something around there.

The point is they handle rediculous amp draws.

The 8000's are also available in 3S (the others I spoke are 2S).

GeeReg · 07.11.2006, 07:57 AM

Those TrueRC packs could be an option.

BP-Revo: That's basically where I've been looking the most.