This power supply will only work as a power supply for the amp and only if you use a bridge rectifier like the one I have at the bottom of my response. Add this and a few filter capacitors to clean it up a little if you are feeling crafty. You will not be able to recharge that battery with this wall wart though. I would only suggest an automatic battery charger that you can get at an auto store. Sadly they do not sell a sla or car battery recharger here at PE. If you can, slurge on a variable amperage version. It's uses will outshine just charging your amp batteries, as they are usefull if your car battery does too.