thats the tranny ratio, not the gear ratio ur using (spur and pinion).
400 pounds to go lipo. nonsense. I've told u 2 times already that a great lipo can be had for 65 bux and the same for the charger. thats 120US. far cry from ur 'quoted figure'.
ALL BATTERIES need constant attention. in fact while ur just recharging ur lipo for another run, u'd otherwise be givin ur nickels alot more ATTENTION when u rest them, yeh really dont wanna use them more than once a day, so pull the next 1, discharge that 1, equalize it, then charge it up full.
lipos catch on fire, nickels explode. the former occurs if u act foolishly. modern chargers work like u've not seen before in controlling the charge of a lipo. til then ur just wasting time, and honestly with the batts u say u have. thats ur biggest prob. not ur motor.
save urself some grief and go faster.