Some of the Automobile type chargers have a "Gell Cell" position. That's the kind of 12v battery that is most likely in your box. They are commonly used in emergency lights in commercial buildings.
I have a Schumacher digital automobile 10A/2A charger with a gell cell setting that I use and I set it on 2A charge. I also have a 500ma wall wart from Tower but it doesn't shut off.
Power panel batteries can be charged by plugging charger into
the starter jacks on the power panel.
http://www3.towerhobbies.com/cgi-bin...&I=LXJC38&P=ML
http://store.schumachermart.com/sc-1000a.html