Battery Exploded

[Full Circle 473]

One of the house batteries exploded. Would like some advice as to what I can check before I replace them both. The boat is equipped with 2 of the deep cycle batteries installed in series and 1 starter battery. All the batteries were installed 3-4 years ago. (before we got the boat). The second house and the starter battery seem fine at this time. Output voltage remains at 13.8 volts. I plan on replacing both house batteries but want to check out if there is a system issue first. What should I be looking for?

 

[KD3PC]

charger age, and such...what is it putting out, voltage wise, and current...not connected, then connected and then with the batteries down.

alternator output voltage, noise, etc

What was the battery/boat doing when it exploded? What is the battery technology?

Fuses blown?

 

[Davidasailor26]

To KD3PC's questions I'll add:

Were both batteries connected in parallel at the time, or was one switched on and the other off?

What kind of "exploded"?

Is there any evidence of a large gauge cable shorting against ground?

 

[Benny17441]

Make sure all the connections are tight and check the output voltage of the charger. If it is a smart charger put it through its paces as it switches stages from bulk charge, absorption charge and float charge. Take a 12V battery and discharge it some and then connect to the charger. At bulk rate the charger should never exceed a voltage of 14.3V. In the next two stages the voltage should taper down to a maximum of 13.4V in the float stage. If the charger significantly exceeds on the high side these two voltage limits it may be overcooking the batteries. Just because only one battery was affected it does not rule out a system fault as it is usual for the weakest battery to fail first disrupting at that time the process. On the other hand batteries can and will fail sometimes with explosive results through no system fault. Make sure the connections are tight to avoid the creation of sparks. Have had a similar failure (not explosive) with a failed voltage regulator on the alternator. Check also the output voltage of the alternator.

 

[Full Circle 473]

The top of the battery blew off the body and got destroyed. There are no shorts or any other issues. The house batteries are installed in parallel. The starter battery is on separate circuit. Both circuits were and are still operational. No fuses or breakers blew.

 

[dlochner]

What kind of batteries? Sealed, AGM, regular old flooded lead acid golf cart batteries? It doesn't look like any heat damage, but then again, a hydrogen explosion is pretty quick and may not have charred anything.

 

[SG]

Lead acid batteries (including convention, Gel, and AGM ones) out gas a bit.
The AGM (except when equalizing, if you try that) probably the least. Gel cells a little; and, wet cells the most.

Years ago there was a Hinckley that burnt down to the waterline because the gel cells were "sealed" in.

So give us some more info on the type, the installation (box or cabinet or...), etc.

 

[Justin_NSA]

I blew up a car battery once. A shorted starter sent the battery current straight to ground.

 

[Full Circle 473]

The battery installation is in the engine compartment, open to air, sitting in a tray. The batteries seam to be sealed. There is no "burn" damage at all. Just the battery itself.

 

[SG]

Maybe the vents were clogged. Had you been running the engines?

 

[Full Circle 473]

Engines were not running, but I really don't know when it blew. This time of year I only get to the boat about once every two weeks. Run the engine every time for about 10 min. Boat is plugged into shore power full time? There are no vents on the battery, it is sealed. My guess is that the battery shorted on the inside and offgased until the pressure blew off the top. Just a theory.

 

[jssailem]

It reinforces the idea that we need to have good fire extinguishers with the correct chemicals.