Is this cell going in your car? If so, you may want a 13.8 volt PSU. If it is staying in your house, then you can run it off of a 12 volt PSU. I am using a 650 watt ATX PSU that runs 52 amps on the 12 volt rail, and thats plenty for me! If you are not putting it in your car, go the atx route and buy a big one that has more power than you think you will need. I would get at least a 500 watt that can run 35-40 amps on the 12 volt rail. that will probably run you 50 dollars. Just for comparison, a 40 amp continuous lab PSU is in the multi hundred dollar range. My 52 amp was only 66 dollars, but if I bought a 52 amp lab power supply it would probably be 300 dollars...