Modded PC power supply for charging

hmm i figured that would be the answer just couldnt help myself but ask. so iether i use this to slowly charge my cells or use it on low capacity batts?? then i guess im going to get me a bigger supply then. thanks alot. and when i make the connections do i hook up +12 and then -12 or +12 and GND ??? that is what is confusing.