This baby won't last a week, it's bound to give up the ghost soon (pun intended). And looking at the mess you've made, I'm pretty sure you've voided the warranty!
When I opened the charger, it turns out the white wire is attached to a connection on the PCB marked "Out +", but the black one is loose so I don't know where it used to be. There are two options next to where the white wire is, one marked "Out -" and the other "ID"; also slightly further back there's one marked "ADJ". Anyone know which of those the black wire is meant to go into?
Sorry if this should be obvious, but I'm a bit of a noob... :}