looking for a decent ps

[scarletboa]

my 200w charger is much much better than my old 50w charger but the problem is my old, dying spare car battery doesn't like putting out more than 100w before the voltage drop becomes a real problem. i have been using a 5a car battery charger hooked up to the battery and the charger at the same time, but the voltage fluctuates too much. i was looking into getting a decent power supply that can power my charger and maybe a 2nd 200w charger at the same time.

this is what i was looking at:http://cgi.ebay.com/Silent-600w-DUAL...ht_1769wt_1165

the ps claims 600w and it is only $20 shipped. i'm thinking yes, but i just want to make sure i'm not buying a POS instead of a PS.