Coach Battery Melted.....

[shajoe44]

I went to check my batteries under the steps yesterday while at ballgame and discovered the mess shown in the picture. One of the house batteries had melted. It was not like this two weeks ago at ball game. I spent two nights at local campground and used their electrical hookups last week but didnt have any noticeable problems while their. Just was curious as to what may have happened.

Thanks

 

[bucks2]

Overheated and melted batteries are often a result of running out of water. The charger believes it needs a charge and continues charging and the battery overheats and melts. Batteries which have shorted internally due to plate sulfation or breakage will also melt down.

It can also be a result of the charger not correctly reading that the battery is charged and it continues to charge and boil out the water, then melts the battery.

If it was mine, I'd take good pictures of how each of the wires is connected, maybe make a diagram and/or mark any wire which could be mistaken for another. Take all the batteries out, clean and neutralize the entire compartment. Paint or otherwise protect any area that needs attention. Put new batteries in and check the charging voltage. Then, monitor the charge process and water levels closely for a week or more to determine that the charger is working correctly.

You didn't say how long it had been since maintenance was done or how often you check the water levels so it's purely speculation what happened.

Ken

 

[donn]

Guess you should count yourself lucky it did not burn your RV to the ground.  Proper battery maintenance is crucial.

 

[shajoe44]

Thanks for the answers. I am going to take it to the Interstate dealer that installed the batteries and let him put some new ones in there.

 

[John Canfield]

Overheated and melted batteries are often a result of running out of water. The charger believes it needs a charge and continues charging and the battery overheats and melts. Batteries which have shorted internally due to plate sulfation or breakage will also melt down.

It can also be a result of the charger not correctly reading that the battery is charged and it continues to charge and boil out the water, then melts the battery.

If it was mine, I'd take good pictures of how each of the wires is connected, maybe make a diagram and/or mark any wire which could be mistaken for another. Take all the batteries out, clean and neutralize the entire compartment. Paint or otherwise protect any area that needs attention. Put new batteries in and check the charging voltage. Then, monitor the charge process and water levels closely for a week or more to determine that the charger is working correctly.

You didn't say how long it had been since maintenance was done or how often you check the water levels so it's purely speculation what happened.

^^Yes^^

 

[SargeW]

The interesting thing here is that it was a 6 volt battery that failed.  6 volt batteries are pretty tough overall, so there must have been some serious heat there.  And the battery that failed was the one that takes all of the charging input leads.  Make sure that the cables are checked good for damage when the batteries are replaced. 

One thing I like to in my maintenance with the batteries is about every 6 months I switch the 6 volt batteries around.  By changing their positions with each other, the hot leads will attach to the opposite battery each time you swap. 

 

[SCVJeff]

I would be very very careful about extracting that thing. If the water is gone, there are likely gas pockets and that thing is surely alive enuf to generate even a small spark.

 

[Frizlefrak]

Also possibly a loose connection was creating a lot of resistance.....ie heat. 

 

[shajoe44]

Part 2 to the problem: I went and had the 2 batteries replaced Friday. After having them installed went inside to crank the RV and noticed a very very weak cranking. I knew this wasn't right so shut it off. I had no power to the dash, radio, speedometer display or anything. I removed the cover to the batteries and acid had leaked out the top of the same battery position that originally melted down. I disconnected the cable to this battery and taped up the ends so I could go to the game. I talked to a few people and they said maybe cable is bad. One of the cables is definitely burned. Someone also suggested a grounding problem.

 

[Gary RV_Wizard]

A bad cable will cause a lot of heat near the defective area. It is quite possible that the cable end is not firmly attached to the cable, or there is corrosion underneath. Repairing or replacing the cable(s) seems like a good plan.

 

[shajoe44]

Thanks Gary for the input. I have one more question and this hopefully will give me a starting point. I have disconnected the cables from the new batteries and taped the ends up til I could get it back home. Ok this past weekend while driving from the place I keep the RV to the stadium parking spot, which is roughly 3 miles I had no DC power. But on my return trip Sunday I had DC power inside the RV. (I use my Honda 3000 generator while at the games and everything works as usual) OK today I went up and drove the RV back home which is a 2 hour drive. After about 30 minutes I had DC power inside, then I made a stop and turned off the engine. After restarting I didn't have any DC power until once again about 20-30 minutes. Is this a possible cause or effect to my original problem of battery getting overheated or does it sound like I might have 2 separate problems?

 

[Gary RV_Wizard]

The engine alternator will charge the house batteries and it sounds as though they were doing so, but don't know how that happened if you had both wires removed at the battery terminals. Or maybe some of your 12v circuits are wired to the chassis battery?

 

[John From Detroit]

Depending on conditions those batteries can easily be passing 50 to 250 amps through their connections,, Does not take a lot of resistance to make a whole lot of heat at that current level,  That said a lot of resistance will mean a lot of voltage drop.

I do clean and check the fluid level (And addd DISTILLED) water in my batteries often, as they get older I do it more and more often (When they were new it was annually, now it's quarterly)  Last time was last week.  Added 1/2 gallon across the system.  Clean regularry as well.    Electricity is the "Fuel' that powers much of the house, and as the Farmall gas cap says "Buy clean fuel, keep it clean".

 

[shajoe44]

OK, finally had time to investigate my problem a little today. I would like for an expert to look at my battery lead hookups. I have included a hand drawn layout of the connections. All batteries shown are 6 volts. I am just wondering if they were not correctly hooked up when I purchased the two under the steps. I am getting 14.18 volts to the cranking battery when RV is running. I have not hooked the 6 volt batteries back up yet.

Thanks

 

[n7qvu]

The bottom battery on the left has two negs??

 

[Just Lou]

If your batteries are truly wired per the the diagram, they will never work.

They need to be wired as shown in the attached.

The 14.18 volts to the chassis battery, when engine is running, is coming from your alternator (which is good).

 

[Jammer]

Looking carefully at the photos, it appears to me that the steel tiedown shorted to one of the lugs for the battery that melted.  That's probably the cause of the fire, not an internal failure of the battery.  Observe that the center portion of the tiedown is missing, presumably melted, and that the crimped end of the blue battery cable is not insulated and would have been in contact (or nearly so) with the tiedown.

Usually with a shorted cell, there's more damage to the plates than appears to be the case in your photo.

If it were my rig, I'd at least consider replacing the battery cables and modifying the wiring so that there's only one lug connecting to the battery.  Failing that, I'd at least put some heat shrink over the lugs, or at least some tape.  Otherwise you may run into the same problem again with your new batteries.

 

[bucks2]

Lou has corrected your diagram to a workable solution assuming all batteries are 6 volt. Your original drawing as posted is not a working solution.

Lou has put together a 12v battery combination on the left side and a 12 volt battery combination on the right side. Cells inside batteries are connected positive to negative and the voltage becomes cumulative. Eack cell (filler cap opening) in a common 6 or 12 volt battery is 2 volts (nominal, actually 2 point something but we're rounding to make things easy) So a 6 volt battery has 3 filler caps, and a 12 volt has 6 filler caps.

If you examine Lou's drawing he has showed you a positive to negative connection between the two left side batteries and a positive to negative connection between the two right side batteries. Lou's diagram shows the left pair in "series" and the right pair in "series" and the two "sets" of batteries in "parallel". So you could properly call the setup "four 6 volt batteries connected in series/parallel".

Then he shows both battery combinations positive leads going to the red or positive cable for the coach (which may include but not be limited to charger, starter, alternator, ignition etc) and the black negatives going to the coach (same locations as the red typically) and to ground, which is correct.

Ken

 

[shajoe44]

Thanks for the update. Sorry about the confusion with the two negatives on that one battery. Should have been positive upper left and neg bottom right. I am going to send all this information to the interstate dealer that installed these.

 

[shajoe44]

Here is picture of battery after being removed.