Be careful.We had a doctor in our area try and charge a PWC battery while the PWC was in the water with jumper cables. He was electrocuted.I guess knowledge in medicine doesn't mean you know anything about electricity dangers around water.
With jumper cables? Not possible. 12 VDC doesn't shock you that way. Now maybe if he was using an 110VAC charger
Well I do know they can explode as I had that happen to me one day when my car, 77 Monte Carlo, wouldn't turn over I popped the hood jiggled a loose terminal and POW like a gun going off in my face. I recall it was a hot day and I had been on the road a while and had stopped for gas. I walked into the station with my eyes closed, stripped clothes, flushed eyes had the gritty feel of acid on my teeth and a chunk of plastic sticking out of my forehead. Lucky I guess.I think my brother shat himself but got a new battery in hosed things down and on our way.
as batteries are being charged they produce hydrogen gas. That's why you should always turn your charger off before disconnecting. That's also why you remove jumper cables from the "live" vehicle first.
Wasn't on a charger just driving from Syracuse to Vermont.