AGM batteries on fire!

[ScoBlair]

Just brought my MH (FR Georgetown GT7) home from storage, to get ready for a long trip. Suddenly, saw smoke pouring out of the furnace vents, and found my new AGM house batteries had exploded and caught fire. Heard a couple pops just before I stopped. Nothing was on inside, just the engine running, and the batteries were disconnected at the toggle switch. Only charge was from engine, nothing else. Fried the wiring, and our trip - anyone else had this problem? Replace batteries <3 months ago, and worked fine on 2 recent trips.

[cadillac_al]

I would guess they grounded out somehow. Do you see any evidence of the positive cables or post shorting out?

[Old Scout]

Doesn't seem to happen very often, but our brand of DP [fleet of approx. 1200] had 3 reported battery fires--all were relatively new AGMs, and all were while under way [Cummins engine running].

[Arch Hoagland]

What brand of battery were they?

[shootist]

Originally Posted by Old Scout

Doesn't seem to happen very often, but our brand of DP [fleet of approx. 1200] had 3 reported battery fires--all were relatively new AGMs, and all were while under way [Cummins engine running].

3 in 1200 is a huge number, can you imagine 1 in every 400 cars burning down.

[Fridge Defend]

Originally Posted by ScoBlair

Just brought my MH (FR Georgetown GT7) home from storage, to get ready for a long trip. Suddenly, saw smoke pouring out of the furnace vents, and found my new AGM house batteries had exploded and caught fire. Heard a couple pops just before I stopped. Nothing was on inside, just the engine running, and the batteries were disconnected at the toggle switch. Only charge was from engine, nothing else. Fried the wiring, and our trip - anyone else had this problem? Replace batteries <3 months ago, and worked fine on 2 recent trips.

Sorry for your loss, please carefully gather the facts

Please post your findings when you have completed an investigation into the cause of the fire.

As engineers, we are constantly monitoring the facts so we can improve safety.

Your facts may help others supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.

Some considerations:

1. Were the batteries on a circuit breaker or fuse, if so what size?
   
2. What size cables were the batteries using, and are these the same size cables used in the past with similar configuration (number of batteries, ...)
   
3. Were there any loads on the batteries? Fires are often caused by a load such as an air conditioner that draws a lot of power. If so, what circuit breaker or fuse was used on this load?
   
4. Look for the part of the fire where the most damage is, if you send in a photo this can help.
   
5. If there is a proper investigation by anyone, please share the results

.

V=IR & P=VI always, Paul and Mao

[ScoBlair]

Everything pretty toasted/melted by the fire - could not sort out anything.
Worked fine on 2 recent trips last month.

[ScoBlair]

Originally Posted by Fridge Defend

Sorry for your loss, please carefully gather the facts

Please post your findings when you have completed an investigation into the cause of the fire.

As engineers, we are constantly monitoring the facts so we can improve safety.

Your facts may help others supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.

Some considerations:

1. Were the batteries on a circuit breaker or fuse, if so what size?
   
2. What size cables were the batteries using, and are these the same size cables used in the past with similar configuration (number of batteries, ...)
   
3. Were there any loads on the batteries? Fires are often caused by a load such as an air conditioner that draws a lot of power. If so, what circuit breaker or fuse was used on this load?
   
4. Look for the part of the fire where the most damage is, if you send in a photo this can help.
   
5. If there is a proper investigation by anyone, please share the results

.

V=IR & P=VI always, Paul and Mao

Fire started while I was driving from storage lot to my home, about 3-5 miles.
Battery disconnect was off - ie, battery supply was disconnected, nothing running on the house system.
Batteries connected with original battery cables, 4 in parallel configuration, exactly same as original system. Previously had flooded lead-acid batteries, which failed after 2 seasons, and replaced with same size AGM batteries - Duracell brand.
Just brought it to the dealer, to see if this can be repaired - probably will start to investigate early next week. Not too hopeful, found lots of other electrical functions not working - side cameras (activate with turn signal), electric driver chair adjustments, rear camera, electric motor for steps, and parking brake sensor.
Not sure if I can attach a picture.
Let me know if any other questions - just have not heard this happen before. And this was not an extremely hot day, either. Very confused, but do not want to experience this again!

[ScoBlair]

Originally Posted by Arch Hoagland

What brand of battery were they?

Duracell batteries - brand new in March 2023, bought from Batteries Plus in store.

[ScoBlair]

Although not connected to shore power, does the inverter setting for the charger affect this? Flooded vs AGM1 vs AGM2? The fire/explosion occurred just from driving and charging from alternator and engine.

[Mark_K5LXP]

I have no idea what happened and hopefully it can be sorted out. Just as a data point lead acid batteries are pretty much non combustible - mostly metal and liquids that cannot be made to burn. It's the stored energy going through external conductors- wires, metal chassis, that gets hot from wayward current and those or surrounding items are what burns. So this pretty much underscores what's said above, they somehow shorted and having a battery shift while in motion and touch something, or a cable rub through or flex and break is not unheard of. With any luck the damage is confined and readily repaired.


Mark B.
Albuquerque, NM

[Ray,IN]

Originally Posted by ScoBlair

Although not connected to shore power, does the inverter setting for the charger affect this? Flooded vs AGM1 vs AGM2? The fire/explosion occurred just from driving and charging from alternator and engine.

The inverter/charger must be connected to 120VAC to work; that means shore power or genset power.

[153stars]

AGM can accept slightly higher charge and float. Shouldn't be damaged by a modern 3 or 4 stage charger on flooded setting or alternator unless voltage regulator has failed high.
A few owners have had over or under charging due to bad temp sensor to inverter charger.. More often under charging.

Originally Posted by ScoBlair

Although not connected to shore power, does the inverter setting for the charger affect this? Flooded vs AGM1 vs AGM2? The fire/explosion occurred just from driving and charging from alternator and engine.

[Old-Biscuit]

Previously had flooded lead-acid batteries, which failed after 2 seasons,

What do you mean by failed?
2 seasons........something is going on