Ever been in a telecom companies facility? they use -48v DC to power all the telecommunications gear... they use LARGE lead-acid batteries.. they're designed for this application, as well as ease of service..

I'd love to find a place to get these surplus... or build them..

I have a old Hercules multi-fuel diesel I picked up cheap (and another that belongs to my father-in-law), I plan to couple each of these to a generator head, and I can have a multi-fuel generator... they may be weak for pushing a heavy 6x6, but they're good for up to 50kW of generator (waay overkill) would like to get a 6-pole gen head, to run at 1200rpm...