Dead house battery

Thankfully no harm was done, but my very old Diehard marine battery went bad. It was at the stage it could have exploded though!

About a week ago, my CO detector woke me up about 9am for no apparent reason. I thought perhaps the batteries in the detector were getting low or the detector is just aged and needs replacing.

Later on that day, I saw my battery voltage reading was unusually low so I plugged in my RV converter. I should have realized something was wrong at that point. Normally I have it unplugged since my solar panels keep the house battery bank charged. At 4pm, I shouldn't be showing 12.3V. I should be showing 14V from the solar charging!

I exited the van for about 10 minutes and returned to find 'rotten egg' smell, but not from any of the propane burning appliaces or from the propane tank storage compartment! It was coming from the battery box! The box is vented to outside but not airtight from the interior. I opened the box and the odor was strong and the old battery was burning hot.

I quickly unplugged the RV converter and disconnected my solar panels. After allowing it to cool down about 5-10 minutes, I promptly removed the bad battery and placed it outside. Thankfully, I caught it in time before it exploded. I was a bundle of nerves disconnecting it and hauling it outside.

I am holding on to it for core exchange since I will be getting another cheap marine battery next week. In the long run, such batteries are a waste of money but in the short term, it's 1/3 the cost of a pair of 6V Trojan T-105s, or rougly 1/2 the cost of a pair of cheap golf cart batteries. Plus I would have to modify the battery box I already built. I used scrap wood so I was limited in the size I could build it, so it ended up too short for 6V golf cart batteries.

It has crossed my mind to pull the old, worn out generator and install 6V golf cart batteries in it's place, but I'm not going to right now. I may do that in a year or two, if I decide I need more battery power. I would probably need a third 100W solar panel to keep up with the battery bank. I did install my first two in such a way that I have room for a third by removing the RV antenna so it's possible to do. Just not something I want to do right now. It would cost roughly $500 to add a pair of Trojan T-105's and a third solar panel so I may budget for that later on.