Exploding Battery

[Cracker]

Sometime during the night, about two days ago, my street-side battery exploded and blew the compartment door open! It bent the latch arm out straight and, when I went to disconnect the 20' extension cord running from my 30 amp service, I found that one of the plug prongs was melted into the female receptacle. The trailer is currently stored in my drive with the air-conditioner set to 78 degrees. It has been that way for the past two months except when we travel. I had not checked the level of the acid for some time - however, in the past, I have virtually never experienced any loss of acid. What I believe happened is that the acid got low in the battery that exploded and the charger just kept running until the battery overheated and the gases exploded. The other battery has one cell that is seriously low (1/2) but it is otherwise intact - although defunct. There was no damage to the battery compartment other than the bent lock arm. What puzzles me is that I would have thought that, under the conditions described, the circuit breaker (---house or trailer) would have tripped before melting the rubber plug??? It is, of course, my fault for failing to check the acid level - if that was the cause of the problem - but otherwise, I've used this same maintenance procedure every summer for close to 10 years. This is my third set of batteries - the others simply failing to maintain a charge after about 3 or 4 years. The batteries in question were installed in 2008. I'm hesitant to replace the batteries without some sound input into what may have caused the problem - i.e., is the converter/charger trash, or could the low acid level alone have caused the problem?

[Wayward]

Did the battery itself explode (with acid and internal components breaking through the case). Or, did the compartment explode?

The reason I ask is I'm wondering if hydrogen gas is building up inside the compartment and being set off bay a spark or heat source. Lead acid batteries in a closed compartment should have have a vent tube leading outside.

Either way it sounds like overcharging. From what I have read here, the OEM supplied converters in the Airstream are not smart about charging and are not ideal for extended charging. Unless you need the batteries for say two months, it might be better to disconnect them and keep a smart "maintenance" charger on, or upgrade the converter.

[richinny]

i've read here that if you have a bad battery in a 2 battery set-up, the converter will constantly try to charge the bad battery thereby overcharging the good battery.

the melted connector could be due to an overload, poor quality or a dirty connection.

[SteveH]

Sad to say, that's one of the things that batteries do. I had one explode about a year ago while we were in a RV park plugged in. I had a smart three stage charger and actually think it was a contributing factor.

One of the batteries developed a shorted cell (the one that did not explode), but the charger saw the lower voltage of the system and started trying to bring the battery back by raising the charge voltage to an equalize level. Of course the voltage was accross both batteries, and I don't know why, but the one without the shorted cell exploded.

Same damage as yours, Cracker, except acid went all over the place as well. Had a baking soda washing party to neutralize it.

I'm of the opinion that these kinds of batteries should just be replaced every three years.

[Mexray]

As you are now aware, the electrolyte was depleted to the point that the internal battery plates and active material dried out, probably crumpling over time and possibly 'shorting' between plates...it only takes a small 'spark' to ignite the hydrogen gas present...BOOM!

I would suggest you invest in an up to date, 3-stage type converter/charger - especially if you leave your AS plugged into shore power all the time...these modern C/C's lower the voltage when in 'float' mode to preserve the electrolyte fluid level, and help insure longer life of your batteries...

I suspect your 'plug' fusing problem was due to the higher current load during continued AC running...it takes a lot of 'heat' to fuse those prongs, and could be a BIG problem is there are any combustible materials nearby...

A clean, bright plug connection (to reduce electrical resistance) will help avoid many damaged plug problems, but it's usually an 'overload' condition that does the most damage...make sure your plugs are tight in the sockets, as some AC sockets become worn over time and can contribute to the problem...

Don't forget to use a baking soda/water solution in your battery compartment to help neutralize the acid that was splashed around inside - then flush with plenty of fresh water from your garden hose...

Happy trails...

[Cracker]

Originally Posted by SteveH

Sad to say, that's one of the things that batteries do. I had one explode about a year ago while we were in a RV park plugged in. I had a smart three stage charger and actually think it was a contributing factor.

One of the batteries developed a shorted cell (the one that did not explode), but the charger saw the lower voltage of the system and started trying to bring the battery back by raising the charge voltage to an equalize level. Of course the voltage was accross both batteries, and I don't know why, but the one without the shorted cell exploded.

Same damage as yours, Cracker, except acid went all over the place as well. Had a baking soda washing party to neutralize it.

I'm of the opinion that these kinds of batteries should just be replaced every three years.

I had the same acid problem except that it all seemed to blow out through the open compartment door onto the driveway. My driveway is a bit lighter color now in the spill area but not too much got on the trailer. The end of the battery toward the compartment door demonstrated the greatest damage from the explosion - although both of the battery caps were blown off too. As I said before, there was hardly any signs of damage to the battery compartment. My most significant question is whether or not to trust the charger again. One other interesting note is that I just got my electric bill and it is at least 25% larger than I've ever had before. Methinks the charger may have been running overtime for quite a while! Incidentally, these Airstream compartments appear to be fairly well vented to the outside at the bottom of the compartment.

[SteveH]

Originally Posted by Cracker

I had the same acid problem except that it all seemed to blow out through the open compartment door onto the driveway. My driveway is a bit lighter color now in the spill area but not too much got on the trailer. The end of the battery toward the compartment door demonstrated the greatest damage from the explosion - although both of the battery caps were blown off too. As I said before, there was hardly any signs of damage to the battery compartment. My most significant question is whether or not to trust the charger again. One other interesting note is that I just got my electric bill and it is at least 25% larger than I've ever had before. Methinks the charger may have been running overtime for quite a while! Incidentally, these Airstream compartments appear to be fairly well vented to the outside at the bottom of the compartment.

I questioned my charger after the incident also, so I replaced the batteries, and monitored the voltage for a while (a few days), and all was well. I had no more problems with it, and traded the trailer last January.

[Ag&Au]

Originally Posted by Cracker

.............................

Incidentally, these Airstream compartments appear to be fairly well vented to the outside at the bottom of the compartment.

Since hydrogen is lighter the air, it must be designed that way to allow maximum hydrogen accumulation before the hydrogen bomb goes off. In your case it worked to perfection, blowing the acid out onto the driveway clear of the trailer. I can't believe I initially thought it was a bad design.

Ken

[SteveH]

Believe me, if you are in the trailer as I was when it happened, it most definately does sound and fell like a bomb.

[Phoenix]

Quote from Cracker's original post:

"One other interesting note is that I just got my electric bill and it is at least 25% larger than I've ever had before."

I think you answered your own question in this extract from your original post:

"The trailer is currently stored in my drive with the air-conditioner set to 78 degrees. It has been that way for the past two months except when we travel."

Air conditioners (ACs) draw a tremendous amount of current compared to most other household appliances. Our 5-ton, 220-volt AC unit increases our home electric utility bill by over $200 per month in the summer; so $75 is probably about right for the smaller, 110-volt RV air conditioner on your Airstream.

Regarding battery problems, I hate to keep re-posting the same suggestion; but conscientious use of a marine battery isolator switch will pretty much eliminate battery overcharging and phantom drains, and extend battery life in storage. See link below, provided for reference only.

Amazon.com: Perko 8501DP Marine Battery Selector Switch: Automotive

[Ag&Au]

Originally Posted by Phoenix

Quote from Cracker's original post:
......................................


Amazon.com: Perko 8501DP Marine Battery Selector Switch: Automotive

I put one of those in my Bigfoot trailer. During the winter I would go out and turn it on for a couple of days every few weeks to keep up the charge. I thought our Airstream had a similar switch, until I found that it left the batteries connected to the charger and just disconnected the load from both. I am either going to rewire the existing switch or put in another Perko. The Perko is so impressive looking that it should be mounted in the open to be admired by all. The label on the both position should be changed to "LAUNCH"


Ken

[Phoenix]

I mounted this switch on the side of our battery box. Send me a PM, if you would like photos and installation instructions. --Thanks.

[Protagonist]

Originally Posted by Cracker

I've used this same maintenance procedure every summer for close to 10 years. This is my third set of batteries - the others simply failing to maintain a charge after about 3 or 4 years. The batteries in question were installed in 2008. I'm hesitant to replace the batteries without some sound input into what may have caused the problem - i.e., is the converter/charger trash, or could the low acid level alone have caused the problem?

Don't be hesitant. If you replace batteries every 3~4 years, and these were installed in 2008, then now in 2012 they'd be about due for replacement anyway, even if you didn't blow one of them to smithereens.

Originally Posted by Cracker

Incidentally, these Airstream compartments appear to be fairly well vented to the outside at the bottom of the compartment.

They're better be vented at the top, too. Hydrogen is lighter than air, and will always rise. Hydrogen will not vent out through a bottom vent; that's to drain any fluids (condensation) that might get into the compartment, and to provide intake air to replace the whatever goes out the top vent.

[SteveH]

Originally Posted by Protagonist

They're better be vented at the top, too. Hydrogen is lighter than air, and will always rise. Hydrogen will not vent out through a bottom vent; that's to drain any fluids (condensation) that might get into the compartment, and to provide intake air to replace the whatever goes out the top vent.

The battery compartments on the trailers are far from air tight. They are vented all over the front. They just have a place at the bottom for fluids to drain, and evidently that's important.

[Ag&Au]

Originally Posted by Protagonist

They're better be vented at the top, too. Hydrogen is lighter than air, and will always rise. Hydrogen will not vent out through a bottom vent; that's to drain any fluids (condensation) that might get into the compartment, and to provide intake air to replace the whatever goes out the top vent.

If his are anything like mine, they don't have a top vent that I have ever seen. However, the door is pretty much all of the front of the battery box, and it's not really sealed to speak of. I think any hydrogen gas that is not in the battery would vent fairly quickly around the door edges.

Ken

[Cracker]

With respect to my larger electric bill, this isn't the first summer I've run the A/C at 78 degrees for an extended period. That's why I was leaning towards the charger running non-stop as the cause. As for the melting plug, my first move will be to change the female end of the extension to a high-quality hard plastic. Next, thanks to some driveway modifications, I can now move the trailer closer to the house plug and do away with the extension. With respect to the OEM battery switch behind the couch, what purpose does it serve if it doesn't take the batteries out of the system - as stated above??? I assumed that it would indeed remove the batteries so that the 12 volt converter could still run the 12 volt trailer systems when plugged in to shore power - without charging the batteries. Can someone else help to clarify this? Further, I would think that, due to the batteries being required for the emergency break-away system, power would still flow thereto regardless of the position of this switch.

[Ag&Au]

Originally Posted by Cracker

......................
. With respect to the OEM battery switch behind the couch, what purpose does it serve if it doesn't take the batteries out of the system - as stated above??? I assumed that it would indeed remove the batteries so that the 12 volt converter could still run the 12 volt trailer systems when plugged in to shore power - without charging the batteries. Can someone else help to clarify this? Further, I would think that, due to the batteries being required for the emergency break-away system, power would still flow thereto regardless of the position of this switch.

I believe the break-away switch is wired directly to the battery. In any case I would not travel with that switch in the off position. As far as what good the switch is wired as it comes, it supposedly is for when the trailer is not in use and takes almost all the load off the batteries so they will discharge more slowly. Everything I am saying applies to my trailer only as I have not checked others. However ours was purchased new and no mods have been done to it yet. However, the warranty has now expired and I plan to make a few things the way I want them. I discovered this the first time we camped. We plugged into shore power and then I turned the switch off expecting to disconnect the batteries, because I knew they were fully charged. I was quite amazed when the trailer when dark. Referring to the trailers manual confirmed that indeed the switch was supposed to be wired the way it is.

It will be a simple matter of adding one short battery cable and moving a couple existing wires from one terminal to another to make it perform as I feel it should.

Yes I agree 100% that is not the way I would expect things to be.

Ken

[Cracker]

To update, I wired in a new Camco female 30 amp plug to my 20' extension and installed two new Interstate RV/Marine batteries today. All is well with respect to the observed operation of the A/C and the battery monitor over the stove. The batteries registered 12.86 volts and 12.88 volts just before I installed them. Currently I've got the A/C running (---still set to 78 deg) and I plan to leave it that way overnight (---all that will do is simply determine if the extension cord gets hot again - or, horrors of horrors, another battery explodes!) Tommorrow I'll check the voltage on the batteries and see if it seems reasonable. I would like to be able to tell if the converter/charger is running (i.e. - "charging"), but other than noting a change in the battery voltages I don't know how? Does anyone know what the maximum voltage reading should be for the batteries??? I've heard that it could be over 13 volts - but what's a ballpark figure?

[Cracker]

OK - today's voltage for both batteries is 13.89. Is this correct for new fully-charged batteries - or is it an indication that the converter/charger is over-charging? Both batteries are cool to the touch - as is the new plug I installed on the extension cord. See post immediately preceding. I plan to unplug the trailer until I'm confident that all is OK. I cannot detect any "humming" from the converter/charger today nor could I detect any humming yesterday. Obviously the charger has been working since it boosted the batteries a full 1 volt. I would appreciate any help resolving this issue.

[TG Twinkie]

You are reading the output of the converter. Turn the converter off or unplug it and I think you will read in the neighborhood of 12.8 volts. Given that you don't have a lot of 12 volt stuff running.