I've got some 6800mah 120c gen ace basher series. Had them 3 or 4 years and they've always tended to puff the hard case if I run till lvc as they are warming up. Then as they cool have somewhat flattened. My last run with them wasn't even to lvc, just stopped to check temps after 5 mins. Didn't bust out of the hard case, but again when cool came back, maybe will try them in a less demanding way from now on. I just got 9200 mah and 9300 mah sets to simply have more mass of battery to try and spreed out the heat and maybe not get hot so fast. Still check temps and don't run till lvc. Also the way you drive depending on the resistance of the terrain can change the heat with out even noticeable change in performance while driving