can you use a general charger for sla batteries. i use a battery tender jr to charge all of my 12 volt small batteries. 22$ on amazon. i use it for my marcum lx7 and lx9.
marcum sells the charger you lost and maybe the will tell you what the specs are. i wouldn't use just any thing on it like a wall adapter. i had a wire fire on a cheap charger that came with a camera. be careful!