This battery
combined with
Imax B6


Total pricetag. £ 35.97 +P&P

Cheaper than any other good solution for your overheating drives. And it will free a lot of weight and space for future upgrades.
Yes, the machine will be slower and will have less torque. But will run a lot more controled and with less maintenance problems.
I know I like the less maintenance situation. It's rather frustrating making emergency repairs during an event on a machine that didn't get any battledamage.