best info I have found
http://www.rcgroups.com/forums/showthread.php?t=1005309
But to figure out how many amps it's rated for, just use ohms law.
I = V/R or current = voltage divided by resistance
I * V = P or current times voltage = power
a watt is a measurement of power.
so 750W / 12v = 62.5A
Just because it's rated at that doesn't mean it will do that. If you run a power supply at 100% capacity for an extended period, kiss it goodbye.
Ideally you want to keep it in the range of 40% - 60% capacity.