The specs on a pc ps are sometimes not up to par. Anyways the yellow wires are 12 v + and the blacks are -

Figure your total load in watts by multiplying the voltsxamps on the output of charger and then the ps needs to have at least that much power and be able to supply the minimum voltage for the particular charger/battery. It works good, and in case it is a bit less powe than you need, just charge slower.

For easy figuring since your output and input voltage match then you could say whatever current you will charge at = the current of the ps (plus 10-20% more)