On board charger question

[helpmelovemyboat]

I was hooking up a bass pro shops 2 bank charger to my battery today (bought the boat used, charger was already installed) and I noticed when I attached the ground wire to starting battery (positive was already hooked up) it sparked a little. The trolling battery was also hooked up to the 2nd bank and charger was NOT plugged in. Is this normal? I always thought that if you saw a spark when hooking something up it meant it was drawing current. Should an onboard charger not plugged in do this? All wires are hooked up correctly.

 

[Silvertip]

Re: On board charger question

Probably a filter capacitor discharge in the charger -- not power from the battery going back toward the charger. No big deal.