Cooked battery about caused a fire

Who can tell me about a cooked battery? Took the little Scout out for a nice day on our beautiful mountain lake and when I got to our dock, I noted a smell, electrical and plastic like. Opened the engine compartment and when I bent down I could hear a fast boiling sound. Felt the three batteries and the third one was too hot to hold my fingers on!!

I feel like I have just avoided a real disaster, but even as I type this it is still too hot to hold my finger on 30 minutes later, but the boiling sounds have stopped. I don't see any evidence of battery acid coming out, no spillage, so I don't think it has boiled all the water out.

I have enclosed pictures of the battery set up. What the heck cause this? A regular should stop the alternator from overcharging right? The thing I find interesting is that it is just one battery of the three that is cooked off.

So I cut the shore power, and turned the battery switches off. Something somewhere has gone haywire, but this type of thing could actually be dangerous.

Anyone ever have this happen? I have heard of boat fires caused by batteries. Here are a few pictures I took. Dern things are hard to get to and heavy.

We had something like that last year after getting the new boat home. Horrible smell. Replaced the bad battery and it was fine and been fine since.

Hopefully that's all there is. I just went back to read the builders notes and this battery is one of the two house batteries in parallel. So I'm now thinking more of the battery as with your case. Dave Martin did a fabulous job on this little boat.

Had to take pictures of how this system is set up.

Hope you turned the charger off. Once the water is gone batteries have a tendency to blow up.

This is often caused by lead sulfate settling on the bottom and shorting out a pair of plates in a cell. Then the cell voltage jumps from 2.1 (12.6/6) per cell to 2.5 (12.6/5) and starts boiling electrolyte until all cells are dry.

Replace the battery and all should be ok.

David

Good catch. Pending on how old all your batteries are may be good to change em
all out.

Sounds like a shorted out battery cell. If any acid has spilled out mix baking soda with water to clean any acid spill.

If you use a meter to read the voltage across the terminals of just that hot battery, you’ll probably find that the voltage is very low - like 10.something. When a cell shorts, that cell is taken out of the picture and you end up with a 10.5 volt battery instead of a 12.6 but your charger is still trying to charge at the higher voltage so the battery takes a LOT of current and gets very hot. This just happened to the battery in my daughters car. It was so hot I could hardly touch it. Let it cool down and get it out of there.

Ken

Thanks guys for your answers. I was afraid it was an alternator or regulator or something in the charting system when the boat is under power as this happened after a 2 hours cruise prior to hooking up the shore power and engaging the charger. So now off to be a contortionist and pull those batteries!

Adopo said:

Thanks guys for your answers. I was afraid it was an alternator or regulator or something in the charting system when the boat is under power as this happened after a 2 hours cruise prior to hooking up the shore power and engaging the charger. So now off to be a contortionist and pull those batteries!

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Boat yoga I like to call it.

There. Got the offending bastard, err i mean battery out so will replace all.

Adopo said:

There. Got the offending bastard, err i mean battery out so will replace all.

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Not so fast! You gotta explain about the Isetta! :lol:

Well....what a fun car right? Long story, wife is really the origin of this and many of the cars. I'm lucking in that she likes planes, cars, and boats. I guess she would like trains too but we haven't tried those lol. We attended what was one of the most fun actions RM has ever had, the Bruice Weiner Microcar Auction in Maddison GA. It was getting toward the end, and she got away from me. Next thing I know I hear Max, the best auctioneer in the business who could sell fire to the devil saying, going once to the lady in the back, and looking around I saw my wife with her paddle up!! So we purchased it and continued the restoration. That action was insane, the largest collection of Microcars in the world, setting major world records. The Peel P50 was the coolest car, and it sold for I think $122,000 or so, and the Messerschmitt Tiger brought the most. The other thing about this is it is a true three wheel version, most are of the four wheel variety.

So I drive this around our lake house neighborhood, which is in the foothills of SC, just above Clemson. It is so funny, because it's only about 13HP, powered by a 1959 BMW 4 stroke engine. I have to race about 50 mph down the hills, and on the steepest I am in first gear by the time I crest them. It's a hoot. You know they made thousands of these, and even drove them over the Alps and in the original Mille Miglia race in Italy.

She normally lives with her larger siblings, but those too are stories as well...and the bed. I had that put in one night when our 1964 Carrier 4 pipe 30 ton chiller went caput, and it was around 100 degrees. This relates to the Isetta. I stupidly left the carb open, and due to the nature of this carb it dripped gas. It was more unbearable than the heat, so back to the heat. But it still made for a really cool "Four Poster bed" don't you think? Yep, we like cars. Now if we could just get a great "trawler" before we run out of time and health....

https://rmsothebys.com/en/home/auction-results/bw13

https://rmsothebys.com/en/auctions/...a-300-three-wheel-special-export-model/292888

Nice collection! I’m stuck with the Italian car bug too, but not to the same level as my budget doesn’t allow.
I’m into lancia, fulvia and appia specifically. I do the restoration work myself. (If I have a break from boat work anyway)

Bmarler said:

Nice collection! I’m stuck with the Italian car bug too, but not to the same level as my budget doesn’t allow.
I’m into lancia, fulvia and appia specifically. I do the restoration work myself. (If I have a break from boat work anyway)

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Oh I love the Fulvia and have wanted one since I saw one in the flesh at Concorso Italiano. And forget about the Stradale, did you see the one on BAT? I go here about every day. I'll PM, perhaps you an tell me which Fulvia to go for. I know they made several variation. I'll PM you for advice. You may have noted the 71 GTV in the garage. I came from Canepa Design in Scotts Valley. Thanks!

The best vintage and classic cars for sale online | Bring a Trailer

Replace the two 12v batteries in parallel (very bad practice) with two 6v batteries in series. That way, when your battery switch is off, one will not be trying to charge/discharge the other.

Brooksie said:

Replace the two 12v batteries in parallel (very bad practice) with two 6v batteries in series. That way, when your battery switch is off, one will not be trying to charge/discharge the other.

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Here is the current set up. David Martin did a fabulous job on this Fairchild Scout adding many custom features. This battery box is one of them.

Good catch and Good call on replacing all. Replacing 1 or 2 in a battery bank just shortens the new batteries life .Remember your battery maintenance routine. you must check the fluid levels. You may just have cooked the battery due to low fluid. I can be an overcharging problem also. With the new batteries a simple check of the fluid level every 2 weeks for a while , to make sure the levels don't go down, is a simple check for your charging system