CRT.5 build - would opinions on my setup choices

[VintageMA]

Originally Posted by dway

I think regular lipos would be a better choice. You are only going to have enough room to run a 4s1p pack at 13.2v 2300mah or a 2S2P pack at 6.6v 4600mah. I don't think either one is a very good option.

dway - Comments like this without any technical support on the statement don't carry much weight around here. Do you have any technical reasoning behind your comments?

I also have 2 of the MaxAmps 3S 5000mAh packs myself, but I actually opted to go with the A123 batteries for several reasons:
-Weight - the weight of a 4S A123 pack will balance out nicely against a 8L and ESC mounted on the other side of the car.
-Amp draw - this buggy weighs like 5lbs wet - the highest peak current draw on my BL LST2 with a LMT 1950/7 and 6S in a 14-15lb truck is 85Amps. So I have no concern with there being a current limiting factor.
-Motor - at 3019kv the 4S A123 puts the 8L right in its sweet spot.
-Safety - I've had 4 2S 3700mAh lipo packs (the Firefox ones from FDM) balloon and swell on me just storing them at ~50-60% charge. This has me very concerned as I live in an apartment and don't have a garage. Even though I store the cells in a metal lock-box - I get worried about fire now. If the A123 cells prove them to me on this installation I may consider getting more of them.

Re: the volt drop on the cells - check out the pdf in my first posting. @25*C w a 30A load the cells show a running voltage of ~2.8v. Just like jhautz - this is why I will run 4S A123 instead of 3S Lipo.

JHAUTZ - I'll post some pics on this thread as I am building. A few questions for you if you've thought out some build issues.
1 - What are you going to be using for the battery mount? This is the one place my customization and craftmanship skills always struggle.
2 - Do you think I should get a UBEC as well for the 4S A123? I was going to try the BEC in the MM - but I know I've read a lot that the MM BEC gets hot even on 3S LiPo.