Using my favorite Voltage Loss Calculator
http://www.electrician.com/vd_calculator.htmlI came up with these figures . . .
Using a length of 275 feet and a wire size of 4/0
and using different amperages for charging, you will get these losses
300 amps = 10.1 volts drop
200 amps = 6.7 volts drop
100 amps = 3.4 volts drop
50 amps = 1.7 volts drop
Of course not all of your generators will be at the end of the cable so your total losses will be less than what is stated above, you could condider this a `worst Case' scenario.
I work in the entertainment business and 4/0 cable is the standard wire size for getting the power from the Building (or generator) to the stage. it's always 3 phase power so there are 5 wires needed including the neutral and ground wire. Ever so often, we will use runs up to 300 feet. I'm going to tell you that it is a REAL JOB to run out 300 feet of 4/0, 5 wire cable.