4s or 5s lion or lipo
 

Ok guys, well I finally got the motor/esc for my 8th scale. I'll be running a feigao 7xl with a BK 9918 esc. Question is should I go 4s or 5s. For the time being I'll be running 12 cell nicd/nimh since I have them sitting around from when I used to race. I'm thinking of building a 4s2p lion pack using the emoli cells due to price. But I'm not set on it yet. I may end up going lipo and would like everyone's opinions. I'm not set on a 4s system, but I'm worried about the 9918 being able to handle the 7xl on 5s.

Thanks,
Pat

Id say 5s because the motor you have (7xl) will run more efficiently with 5s. 4s will work too, but you will not have the same speeds and acceleration. On 4s it will also run longer and cooler. IMHO go for 5s. But if your pleased with the 12 cells your gonna be using for now, 4s would be a pretty big step, too!

what is the runtime for the lipo batterys?? ive never really heard someoen say anything about the actuall time

Ok, but do you think the 9918 will easilly be able to handle the 7xl on 5s or would it get to hot thermal and possibly be damaged.
I've had bad luck in the past letting the smoke out of 2 schulze 18.97's that were in an emaxx with a hacker 9L and only 14 cells.

Also are there any advantages besides weight in going lipo over lion? The thing I really like about the emoli cells is I can build the packs how I want and really get the buggy balanced well, a slightly heavier well-ballanced buggy will perform better on the track than a light off-balanced buggy.

The 9918 should handle it easily. 1 question, is it one of the older ones? The old 9918's had a problem with brake fade. Anyways, the weight difference will be negligable, the emoli cells should be fine in a buggy.

paintballer1331, the runtime is mainly based on how much MAH the lipos have, what motor your running, and what terrain. It is almost impossible to give exact numbers to you. BTW welcome to the forums!

Runtime pretty much depends on your driving style.. With lipo it's lighter, so if you stay on the same voltage, the batteries will last longer.

Sylvester, I got it brand new off ebay. But I don't know if its one of the new or older ones, is there a quick way to tell just by looking at it?

5s Lipo with a 7XL may run inefficiently in a 1/8 buggy. If you haven't gotten the motor yet, an 8XL would be a better choice for 5s Lipo. If you have the 7XL already, then 4s Lipo would be a better choice.

There isn't really a good way to check if your 9918 is old/new. That doesn't really matter anyways, since the brake fade didn't affect all of the Warrior 9918s. The one I got (November '04) had brake fade, and it started doing it at about 150 deg.

Yeah I already have the 7xl. I was originally thinking about just doing a 4s2p, and I'm still thinking that might be the best way to go.

You'd get what would probably be the best weight/performance ratio (weight of the whole buggy with batteries). Even with a 4s2p setup, the power output of the batteries would be about 1150watts continuous, which is more than enough... And the weight of a pack like this is about the same as 12 NiMh cells, but with more runtime.

so your runtime will be like 10 min?? if you just drive around your backyard? or how long are we talking here?

I think the runtime should be at least 15mins depending upon how you drive, as long as nothing overheats.