helps ALOT thanks
so no heat problem if i run the MMM and neu 1515 2.5D/F
on a 4s or 5s pack, thats one of my big worries that and battery placement

5S on a crt is no issue - dream setup with MMM and 1515 2.5df - This is what I have in my hyper st and the chassis i'm sure is narrower

ok guess i'll be looking for a new charger have a ice and it only goes to 4 cells,
and you can get just over 15min. at a race pace on a single pack?

15 maybe 20 if you got a big pack - The bigger hyperions are really nice Duo or 1210i...

Packs wise youcan vary alot from high end Polyquest to much cheap protek/zippy...

dumb question but i'll ask it, if i run twin 3s packs can i still get the same power and run time as a single 5s pack ? if so what size 3s packs would i need, only reason i ask is if i go over a 4s pack i need to get a new charger

You can run 6s i.e. 2 x 3s packs in series - 1515 2.5DF would be ok but you may want to look for a lower KV motor 1515/1.5Y 1500KV.

Ideally you would want to look for a set of Enerland 3s 5000mah packs (polyquest, flightpower, neu 25c/30c) - You can velcro /tape them together for 6s.

You could then use a parrallel adapter to charge them as a 3s 10000mah pack. I'm guess this will take a few hours on your charger.