Connect two 12v rails?

[Beetlebeetle]

I'm converting a Coolermaster 525w Extreme 2 PSU for charging use. It has two 12v rails, each able to supply 12v at 20 amps. When I connect the two together (to theoretically get 12v / 40A) I see no difference in the output when I put a heavily load on the supply. I drew 20ish amps and the voltage dropped to just below 10v.

I think one of the rails is dropping to zero when I connect the two of them so I'm only getting power from one. Is there a way to get both to stay on so I can draw 40A?

Thanks!

 

[mikeporterinmd]

I didn't try to do this. I just connected different chargers to different rails. You need a fairly heavy wire to safely handle 40 amps over distance in a home type environment anyhow. I have six chargers distributed between two rails.

Mike