Battery EXPLOSION RISKS !

[GregOddity]

Owner brings the battery back to the boat after wintering it at home and installs said battery on board. As I was walking by, he asks me for an opinion on why his charger was not able to charge the new battery properly. I get inside the boat and the smell of battery cooking was everywhere. I immediately turned everything off and removed the cables from the battery which was already starting to deform. DO NOT TOUCH A DEFORMED AND HOT BATTERY AS IT IS AT RISK OF EXPLOSION. It took 30 minutes to get my Flir thermal camera from my car and for the battery to regain its normal shape so we could move it to the outside to help cool it. So more at less 30 minutes after disconnecting the battery the temperature was still 102.1 degrees Celsius. 45 minutes later it was still at 85.6 Celsius

The terminals were not made tight. He forgot to tighten the nuts on both terminals and they came loose as I touched the cable. The danger of charging a battery with loose terminals is that the battery goes into Thermal Runaway state and a lot depends on where the battery is stored, ventilation, ignition sources and types of security vents.

The normal operating temperature for this battery should be between 40 and 50 Celsius when charging or discharging.

Charging or discharging a battery with loose terminals can actually lead to a situation like this and can cause a battery explosion on board. Make sure your battery terminals are tight after handling a battery or the cables. If the battery feels very hot disconnect the power and walk away until the battery cools down. Check the cables for signs of corrosion or damage to terminals.

Be safe. Don’t be afraid to ask even what you think may be a stupid question.

 

[elton]

I agree, don't mess with lead-acid batteries. They have a very low internal resistance, meaning they can deliver a huge current, resulting in violent destruction of the battery.

I once bolted an aluminium plate across the top of the battery of a motorcycle, after "lampers" stole the original.

It was all fine, until I sat astride the bike, and my weight pushed the metal seat base down, which pushed down the metal plate, short circuiting the battery.

Within seconds, the battery heated up and exploded, splashing battery acid everywhere within the bike frame. Fortunately I had the sense to use a hosepipe to wash the acid away, before it destroyed the bike, and a salutary lesson was learned,

 

[jiris]

This is a very extreme case, thanks for sharing!
Unfortunately, the danger start much earlier the at the melting point of the battery. At the point of overcharging L/A battery starts to release hydrogen, even before its temperature becomes to rise significantly. This is valid even for valve-regulated units and to some degree for marine-grade calcium battery. Hydrogen/air mix is highly explosive in a wide range of ratios and ignites upon receiving an intense look by your eye.
I was lucky to learn this lesson cheaply a few years ago when hydrogen exploded in my engine compartment. Fortunately, the floorboards were not screwed down. They just lifted up a few cm acting like a safety valve, then fell down again. No damage, no injuries.

 

[GregOddity]

This problem is not confined to size of boat or wallet. More to the lack of expertise or care of the owner. Sadly, is far more common to find damaged leads to the battery banks then it should.

This one is on a Princess Yacht over 40”

This is how they should look or as close to it as possible.

 

[black mercury]

Reminds me of a car I once had. One night while driving I started smelling an acid smell inside the car, got to the point when my eyes starting stinging. Pulled over and lifted the bonnet. Battery was so hot you could have pushed a pen through the plastic casing. I disconnected alternator to get me home, and car started again with no problems. I first thought the alternator was overcharging, but it was the battery itself. It would heat up when being charged.
I wouldn't have disconnected the terminals when the battery was in that condition in case you created a spark. Just turn everything off and wait till any gasses disipitate and battery cools. But thankfully turned out OK.

 

[GregOddity]

Reminds me of a car I once had. One night while driving I started smelling an acid smell inside the car, got to the point when my eyes starting stinging. Pulled over and lifted the bonnet. Battery was so hot you could have pushed a pen through the plastic casing. I disconnected alternator to get me home, and car started again with no problems. I first thought the alternator was overcharging, but it was the battery itself. It would heat up when being charged.
I wouldn't have disconnected the terminals when the battery was in that condition in case you created a spark. Just turn everything off and wait till any gasses disipitate and battery cools. But thankfully turned out OK.

The only reason why I disconnected the terminals is because I touched them and one jumped up. I pulled the other one up as they were not even a bit tight. If the terminals melted and the wires got together it could have made it more interesting. But the big take away of that is that I would not have removed them if they were properly attached to the battery.

 

[RobbieW]

Reminds me of a car I once had. One night while driving I started smelling an acid smell inside the car, got to the point when my eyes starting stinging. Pulled over and lifted the bonnet. Battery was so hot you could have pushed a pen through the plastic casing. I disconnected alternator to get me home, and car started again with no problems. I first thought the alternator was overcharging, but it was the battery itself. It would heat up when being charged.
I wouldn't have disconnected the terminals when the battery was in that condition in case you created a spark. Just turn everything off and wait till any gasses disipitate and battery cools. But thankfully turned out OK.

I've had that experience delivering a J109 Hamble to Plymouth. Half way across Lyme Bay the nav seat felt warm, no heating on board and November iirc, had been motoring all the way. 2 batteries, one very hot. Turn off engine, disconnect very hot batt and carry on. Very hot batt still hot on arrival in Plymouth.

 

[JumbleDuck]

One of the cells in my Citroën DS battery failed, but the Lidl-style battery charger didn't recognize a problem and continued to pump 3.8A amps through it. I consider myself lucky that I got away with a dry cell and the cover on one side popped off by gas pressure. I still charge the replacement battery over winter, but only when I am in the garage/workshop and can keep an eye on the current.

 

[pcatterall]

Great post! In my ignorance I have always thought a bad connection was just that and that the battery wouldn't work properly. I was planning to fit a battery temperature gauge ( when next I can get back to Spain!)
I will make that a priority now!

 

[johnalison]

A salutary warning, but these events are fortunately rare, considering the number of batteries around. On a related topic, I see in yesterday's paper that a woman died when they were charging what I presume was a lithium ion battery in their mobile home and it exploded. I didn't see what the fault was due to.

 

[GregOddity]

Great post! In my ignorance I have always thought a bad connection was just that and that the battery wouldn't work properly. I was planning to fit a battery temperature gauge ( when next I can get back to Spain!)
I will make that a priority now!

Yeah, a bad connection is the starting point of quite a few interesting phenomena in the battery, but here's Nigel to explain. It's a short and to the point read and there's a bit about the temp sensor on batteries. https://www.yachtingmonthly.com/archive/how-batteries-can-explode-and-how-to-avoid-it-3930

 

[MikeBz]

The danger of charging a battery with loose terminals is that the battery goes into Thermal Runaway state...

...Be safe. Don’t be afraid to ask even what you think may be a stupid question.

OK so here is my stupid question. Is the danger of thermal runaway with loose terminals solely due to the potential malfunction of the temperature sensor?

 

[Humblebee]

Good post Greg, thanks for sharing.

 

[anoccasionalyachtsman]

I've had that experience delivering a J109 Hamble to Plymouth. Half way across Lyme Bay the nav seat felt warm, no heating on board and November iirc, had been motoring all the way. 2 batteries, one very hot. Turn off engine, disconnect very hot batt and carry on. Very hot batt still hot on arrival in Plymouth.

Ditto on a new X-402, all three f huge batteries tops had melted in completely on a return from a Deauville race. Fella sleeping on top thought he was ill.

 

[lw395]

Personally I suspect the loose connections were caused by the battery overheating rather than v/v.
Overheating probably caused by drying out one cell. Inappropriate charging regime, and/or not recognising that the battery is at end of life?

Also I think moving a batttery when its internal temperature is grossly high is not a very good idea at all.
ISTM possible that the plastic case will be soft and a risk of internal shorts if it bends out of shape when you lift it?

Sometimes the best PPE you can get is a good pair of running shoes.

 

[rotrax]

As an apprentice in the Motor Trade in London in the early 60's I was standing next to a guy under the bonnet of a Hillman Minx.

He dropped a large spanner which welded itself to the external cell connection bars of the battery, got very hot very quick - as he found out when he tried to get it off, severely burning his fingers.

I stepped back pretty fast, just as the whole top of the battery lifted off, chucking acid everywhere.

He needed the forecourt hose running in his eyes for a couple of minutes before we took him to Moorfields Eye Hospital.

Very dangerous.

 

[PilotWolf]

I worked on a boat with the house batteries deep below the engine room floor level. I was doing the weekly checks im the absence of the engineer, I dropped a spanner and just froze waiting for the bang. It landed between the terminals somehow. Had to take a break after that!

W

 

[anoccasionalyachtsman]

As an apprentice in the Motor Trade in London in the early 60's I was standing next to a guy under the bonnet of a Hillman Minx.

He dropped a large spanner which welded itself to the external cell connection bars of the battery, got very hot very quick - as he found out when he tried to get it off, severely burning his fingers.

I stepped back pretty fast, just as the whole top of the battery lifted off, chucking acid everywhere.

He needed the forecourt hose running in his eyes for a couple of minutes before we took him to Moorfields Eye Hospital.

Very dangerous.

I worked on a boat with the house batteries deep below the engine room floor level. I was doing the weekly checks im the absence of the engineer, I dropped a spanner and just froze waiting for the bang. It landed between the terminals somehow. Had to take a break after that!

W

My pa saw the better part of a spanner disappear when it aligned itself perfectly on a WWII aircraft battery trolley.

 

[PaulRainbow]

Removing battery cables from a gassing battery is extremely dangerous, there is no excuse for it. The battery should have been well avoided until the hydrogen had cleared.

If your battery is gassing (boiling, smell of hydrogen, CO alarm going off etc) turn the main isolators and any charging sources off and leave it alone until the hydrogen has cleared. The tiniest of sparks can ignite the gas and the battery will explode, literally, like a bomb. I have witnessed this first hand, flying fragments of battery case and boiling acid are not good for your complexion or eyesight.

 

[JumbleDuck]

As an apprentice in the Motor Trade in London in the early 60's I was standing next to a guy under the bonnet of a Hillman Minx.

He dropped a large spanner which welded itself to the external cell connection bars of the battery, got very hot very quick - as he found out when he tried to get it off, severely burning his fingers.

I used to work for a man who had spent some of his early career at the Signals Research Establishment (now Qinetic) at Malvern. He was there when a technician dropped a large spanner and shorted out a bank of ex U-Boot batteries which they had as a high current supply. Apparently the batteries survived but the spanner was vapourised. The bang, he said, was considerable.