More power supply help...

[Metallover]

I had a charger that charged my old lead acid batts I use. I soldered deans onto it. The deans plug was backwards. Now when I plug it in the tiny green led flashes very fast. I took it apart and I couldn't find anything obvious wrong with it.

Today I came across a new power supply for an old laptop. It puts out 18v instead of 29v. I want to use this new power supply to charge my two 12v lead acid batteries.

The two things I think I need to do are put a charge limit on the system and change the voltage to something like 15v or preferably ~29v. Anyone know how I could do this?

Left is back of old ps, middle is ne, and right is insides of old.