boiling batteries

[not2tacky]

Hello,
I’m new to participating in this forum but have tuned in for some time. I’ve had a problem with my 12 volt system since I got into this trailer last summer. No option of boon docking for now as I don’t have enough 12 volt for much more than the trailer jack and lights for a short time when off shore power. The symptom shows up as battery problems-an older one cooks off pretty fast while hooked to shore power and I’ve just abandoned it (as I remember, a few weeks ago I swapped a brand new one in there and it immediately started overheating also). I have been able to pretty well inspect the wiring for that battery compartment back to the inverter/charger and don’t see evidence for an obvious leak. I’m a little afraid I’ve got a dead short somewhere unless it’s related to the inverter/charger malfunctioning. On our last trip, under wet conditions, when connecting the satellite cable I felt a tingling like putting your tongue on a lantern battery when the back of my wet hand contacted some bare metal inside that compartment. I don’t know if this is an indication that something down right dangerous is going on or just typical for the conditions. Anybody out there with experience and wisdom to suggest a diagnosis/quick fix or where I should start (everything in the trailer seems to work just fine off the shore power)? I built and wired/plumbed my own house so have some aptitude, just lack direction being new to the alternate universe of travel trailers. Incidentally, I’m writing this from my work computer so am not able to confirm it, but I believe it has a parallax inverter/charger, though I might just have that stuck in my head from seeing it somewhere else.

[thecatsandi]

Originally Posted by not2tacky

Hello,
I’m new to participating in this forum but have tuned in for some time. I’ve had a problem with my 12 volt system since I got into this trailer last summer. No option of boon docking for now as I don’t have enough 12 volt for much more than the trailer jack and lights for a short time when off shore power.

Well thats a bummer.

Originally Posted by not2tacky

The symptom shows up as battery problems-an older one cooks off pretty fast while hooked to shore power and I’ve just abandoned it (as I remember, a few weeks ago I swapped a brand new one in there and it immediately started overheating also). I have been able to pretty well inspect the wiring for that battery compartment back to the inverter/charger and don’t see evidence for an obvious leak. I’m a little afraid I’ve got a dead short somewhere unless it’s related to the inverter/charger malfunctioning.

A short to the frame is hapeneing somwhere. Not enough to trip a breaker. With everything off put an amp meter in line with each circuit. It should read a very low draw.

Originally Posted by not2tacky

On our last trip, under wet conditions, when connecting the satellite cable I felt a tingling like putting your tongue on a lantern battery when the back of my wet hand contacted some bare metal inside that compartment. I don’t know if this is an indication that something down right dangerous is going on or just typical for the conditions.

This is an indication of something dangerous. Some others have had this problem and it tured out to be the 110 line ot the AC unit was pierced.

[not2tacky]

Makes sense and sounds like a good place to start. Wonder what
I'll do if I find it?

[Smokin Camel]

I have to endorse that advice. Start with your amp/voltmeter and check your AC input first. If it doesn't show up there (though I think it will show)check your output on the charger.

You may want to pull the panel off of your breaker box & be sure your AC is wired in correctly. My hunting partner is an electrical contractor and also knows the RV wiring rules. He has seen some "interesting" wiring in RV's (he is also an arson investigator). The PO may have wired something out of phase which would not do the charger any good.

[thecatsandi]

I thought of something else.
Try this.
Get a 30 to 15 adapter (RV to House). Plug that into a known good GFI outlet.
If it trips then you definately have a 110 VAC leak.

[not2tacky]

Plugged into a good GFI receptical, powered up the a/c & fridge, no problem- didn't trip the GFI breaker. I had the (+) post disconected from the old battery and checked voltage on on it before removing the ground, it showed 2-4 volts - not much of a reading but the needle moved. Then completely removed it,checked the voltage and it looked like about 12V coming from the inverter/charger with no battery. Then swapped in a deep cycle out of one of my boats that had a good charge and it read 12 V after connecting. It's been on about 45 min and don't see any sign of overheating yet. I'll give it a couple of hours and if that holds, will let it go overnight, I sure thought I swapped that other battery in there before but may have been delusional. before I go any further, I don't have any AC load on it at all right now and can't hear the inverter fan running. The batteries may not be demanding any charge because they're not down enough-don't know because my little voltmeter cratered on me for unknown reasons (will pick a better one up in AM). Should I put a little load on it (fantastic fans?) so it will kick on and I can see if it's overcharging? Could it be the old battery just had a bad plate or something and all I need is to go get a good new battery? Of course this doesn't say anything about the little shock while hooking up wet.

[Rebee]

Your inverter should be giving an output 13 to 14 volts. I believe the 12 volts you are reading is the actual battery voltage. If it were mine I would suspect the inverter having a problem. The inverter has an over charge/battery protection circuits, if this circuit is broke the battery will over heat and cause the battery to short out. Check the inverter output with out anything connected to the output.

dale

[ROBERTSUNRUS]

Hi, if I understand what you are saying, then the first thing you need to do is buy two brand new batteries and install them. If you are connecting a good battery to a marginal or bad battery, you will have bad results. Sounds, to me, like you have one bad battery and one fair one; And taking one battery out of your boat and connecting it to the fair one just don't work. You shouldn't get a tingle from the 12 volt system. This is usually caused by a poor connection in the 110 volt system and most likely a bad ground or no ground connection. A little three light polarity tester plugged into an interior receptical inside your trailer is a good test.

[uwe]

If you are not sure what is going on, and if your skills don't produce reasonable results in a short amount of time, then you need professional help. A large percentage of RV fires are of electrical origin.
Please get professional help, so we can enjoy your posts for a long time to come...

[72 tradewind]

What I have found with boiling batterys is that the batterys have failed. First battery in my Airstream started boiling after about a year of light use. Replaced it with the warranty battery, (same type battery) no more boiling. Bought a boat with a battery in it. Seemed like it needed a charge. We were camping in the Airstream so I swapped batterys, boat battery in the Airstream, AS battery in the boat. Later in the day I went to check on the boat battery and it was boiling away so I promptly recycled it.

[rangebowdrie]

The feeling of a "tingling" in your hand, when you touched the metal case idicates that there is the potential of dangerous voltage present in the metal of the trailer. Somewhere in the AS there is a fault, chafed wire inside the shell perhaps, or internal fault in the chargers wiring. Because of the flexing of the trailer, sometimes internal wiring problems can be intermittent in nature. Whatever, get this problem tracked down ASAP, someones life could be in danger.

[not2tacky]

OK, I bought 2 new batteries. installed them and no problems after considerable time connected to shore power. So, inverter/charger must not be over charging, right? Have not checked to see what kind of charge is going to them as the inverter hasn't kicked on (batteries fully charge at purchase I guess). I'll go out and turn the fans on for a while tomorrow to discharge the batteries some and see what I get.

Plugged into a good GFI source for shore power and it didn't trip with the AC and fridge running. Also looked for leaks with my little voltmeter and saw none. Maybe it's a ghost leak that comes and goes after some flexing of the trailer on the road. Maybe it was my imagination to begin with. I'll check it on my next trip in March.

Just thought I'd update those who have been nice enough to reply. Thanks to all.