i hanent tried they're lipos yet but i used to use they're 6 cell nmh batteries and they were awesome batteries. the owners name is mike and he runs the races at the track in lake havasu ,AZ .he used to modify the stock p2k2 motors also and those things were ballistic after he was done with them. his stuff was always excelent qaulity b4 so im sure his lipos r 2 .