Thought we'd been shot at.

[sunshineduo]

We were on our way out for dinner when we thought we heard a gunshot, saw smoke near the front of the coach and then smelled the distinctive smell of sulphur/gunpowder. It was a pretty scary couple of minutes trying to assess whether that could actually be true.
Well, after a few pensive minutes of investigation we found that one of the batteries (now 40 months old) had exploded in its case. How lucky we were to have been nearby to hear it rather than to not know and not be able to address the splattering of acid in the compartment. We are also thankful that the containment system worked as well as it did and prevented damage to surrounding componenets.
We're 3+ years full time now and say on shore power. I've been pretty faithful in topping the batteries (they have needed very little maintenance) and this really surprised me.
So, I have a couple of questions;
Is it indeed smarter to disconnect/isolate the batteries when connected to shore power (could there be any long-term consequesnces to the converter if it has no battery/capacitance to smooth things out?
Has anyone had something like this? We had good venting (I thought) and when I checked it there was no blockage. I'm wondering in a purge fan is in order.



When batteries attack ...

[firetrucker]

Do you have a multistage charger (3 or 4 stages, not just two)? If only two stage charger, your batteries could be overcharging and the cause of the battery exploding. If you have an IOTA, then you should check to see if it has the IQ smart charger that provides four stages of charging and is much better for the batteries.

Bob

[wingerphil]

was parked next to a rig when same thing happened in the middle of the night. Have no idea on the cause but sure made one heck of a noise at 3am.

[Phil P]

Hi

I think firetrucker has a very good point.

If you have been putting much water in the batteries for some time you may want to check your charging system. Batteries when over charged or charged to fast give off Hydrogen gas. It doesn’t take much to make Hydrogen ignite.

Phil P

[swanny]

what converter do you have?

[Ozz]

I think it was just a very uncommon failure of the battery. It could have been an accumulation of Hydrogen gas (Inside the battery) which would be normal, and a short inside the battery providing the spark for ignition, not normal.
Now that you have one older battery, or more, you didn't say haw many batteries you have. Install all new batteries, don't mix an older battery with a new one. The 3-stage charger is a must for RV systems, I recommend that for you, if you don't have it, like Bob said.
Scary deal. Take care and good luck
Ozz

[swanny]

Searched and found this.

The most probable cause of internal battery explosions are from a combination of low electrolyte levels below the plates in the battery, a low resistance bridge is formed between or across the top of the plates, and a build up of hydrogen gas in the cell. The low resistive bridge is called "treeing" between the positive and negative plates. When current flows in the battery, a spark can occur and ignite the residual gas in one or more of the cells. A second possible cause is a manufacturing defect in the weld of one of the plate connecting straps causing a spark igniting the residual gas. Another source of internal battery explosions is caused from a direct electrical short across the battery's terminals. The battery rapidly over heats form the high current and can explode. The largest number of internal battery explosions occur in hot climates due to the loss of water in wet "maintenance free" and low maintenance starting batteries. Most internal battery explosions could have been prevented if the plates were always covered with electrolyte. Please see Section 3 for more information on preventive maintenance.

kevin

[K&Gs3400RL]

So the possible cause has been addressed. How about if connected to shore power for a long time when full timing should you switch the Battery's off? And if so for How Long?

[2 for Him]

Sunshineduo,
Personally the first investment I would make after the new batteries and box would be remote voltage and amperage meters that are CLEARLY visible in the interior. A high voltage or high amp charge for a long time would have indicated the (probable) short in the battery that boiled the cell dry in just a few days, then Swanny's scenerio occurs. I got mine online for less than $30, big red led readout that I can't miss, shoot, thought I had a picture in my skydrive-guess not. I have gotten so used to where the values are normally I can tell when my solar panels need cleaning or if the scare lights are on at night. JMHO
Tom

[2 for Him]

Still forgot to answer your question,
If your multistage charger is working properly I wouldn't disconnect the battery, they need a float charge to keep them healthy.
Tom