Lipo batteries might be fine. I'll stick with the NiMH batteries that are culls from a Prius battery rebuilder in Sanford NC. I currently have 108 of his 6.5 amp 7.2volt Panasonic batteries. I used them on a MinnKota with a Torqeedo prop, and now on a Torqeedo 801. The batteries require a NiMH charger and there aren't that many around that have the capacity to charge them rapidly. I've been impressed that I can leave them in the garage for a month without tending to them and they don't discharge, even when indiscriminatly tied in a 4s3p configuration. Clincher was the $3 per battery, delivered at my doorstep. I have both the three bladed Torq prop and their smaller 2 bladed prop, and it's hard to establish valid comparisons, but I'm a believer. Especially coupled to the brushless Torqeedo motor, it's an efficient propulsion system.