whats acceptable % to take from a lipo during race

[tonydevon]

I think Im needing larger capacity lipo as my stadium truck behaving a bit odd at end of 5 mins final

I put my 2wd buggy 3600 lcg IP pack in there, motor not really turned up but at end of run it cut on me for a second, and I noticed that recharging regularly puts 2100ish back in, so Im taking quite a bit out vs the 3600 capacity

Im assuming I be better off getting a couple of 5000+ lipos for the truck?