Originally Posted by
Wolf Hobbies
The E4FS and E4RS are designed to be LiPo friendly. Unfortunately there is no form factor standard for lipos to follow so it is not possible to predict which batteries will fit.
ROAR did release dimensions for lipo batteries in a 3mm range. It doesnt account for where the plugs exit and things like that but I guess you could answer if packs in that range would fit.