Two battery set up through a perco switch. On board charger hooked directly to batteries, not through perco. When installing batteries, perco off and charger not plugged in, I get a momentary spark on the ground wire to battery. Will not do it again unless you leave ground wire off for a short time. Then it will do it again. Am I just seeing a diode in my charger loading or do I have a problem? Sent from my SM-G955U using Lake Ontario United mobile app