The two ways I have seen a battery explode are over charging caused by a failed alternator regulator and a dim bulb jumping a 6 volt with a 12volt. When a battery is charged at a voltage greater than about 15 volts and at a higher than normal currant it will gas off hydrogen and any small spark will cause it to explode into little pieces. When an alternator regulator fails in a way that causes the alternator to charge at full output 17 to 18 volts are produced at the output. Out put currant will depend on the size of the alternator but most of our boats had around 45 amp alternators as o e . A defective converter that is operating at full voltage and current (assuming it is also charging a battery) could do the same thing. I think most converter installations should bypass the batteries to operate the 12 volt systems. Over charged battery + hydrogen gas + even a small spark = big boom. Put a volt meter on the battery and monitor the voltage with the engine or the converter operating. You should never see more than 14.2 volts. One other possibility is a dead short but when this happens there will be smoke and a fire. Use full face and body protection when working around this problem. Rick

Thanks for the input guys. These are exploding while at dock without the engines running. fortunately I was at the boat both times and was able to clean the mess up rather quickly ( I might add Nothing was on at these times). That's why I was curious about the AC converter. If my thinken is correct does this not function as a dual purpose battery charger and to help prevent an overload from the Alternator when running 12 volt items while motors are on?

Not me anymore. I am getting in the habit of turnning it on when I arrive at the boat from now on out

The temperature of an electric spark is aound 30,000 degrees F. More than enough to ignite anything that burns.

Agreed. Hell, you gotta trust something! I worry more about a leak that draws down the batteries while running the bilge pump.

Jeff

I lost track at some where around 2000 boats I have owned or sold years ago. If you ever see or are on Board a boat wHen the battery blows, it will scare te poopy out of you!! The sound is DEAFINING!! Sounds like a SHOTGUN WENT OF IN THE BOAT WITH YOU!! I staggered outside and sat on the gunnel to clear my ears and head. Another thing s the acid smell inside the boat. Learned my lesson when I opened the hatch and saw the shapnel from the battery casing inbedded in the underside of the plywood engine hatch!!! This accurs as stated above when the battery gets low on water, hydrogen gas fills the void, turn the key, the plates inside the battery spark and BOOM-POOPY ALL OVER THE PLACE!!!! I have seen 3 blow, one as Fastjeff did on my tractor, 2 on boats, last one about 15 years ago on a repo boat, where I foolishly hit the key without checking and the first back in the 70's while welding on the rear deck of a houseboat, where we had trow down a 4x8 ft sheet of plywood over the engine room rear deck. Soon as I struck an arc the spark blew me and him up in the air on the sheet of plywood and came down about a foot!!! POOPY--THESE CAN BE BOMBS!!! I DON'T WANT TO THINK IF IT BLEW YOUR FUEL TANK TOO!!! BE CAREFUL--SORRYDOG

Okay enough. I get the picture. Looks like this weekend project list just got longer, new charger and 3 Brand new Batteries. along with new refridge do in on Fri and new head for forward cabin. hope the weekend last long

I don't even carry a wallet anymore, Money never last long enough to make it there!