Boiling Battery!?

[JenPB]

One of our TVs has a dual battery system involving two 12v Optima batteries. There's a toggle switch that allows us to isolate the batteries from each other or link them (to jump one with the other). This vehicle belonged to (and was set up by) my dad, but he's not doing very well these days, so I'm not sure how much he'll be able to help with the following.

We've had some problems maintaining a charge on one of the batteries. Today, while on a snow run, I noticed an odd sound from under the hood - a very loud bubbling or dripping sound. I opened the hood and immediately spotted the steam drifting out from the battery that was making the bubbling sound.

We were on top of a mountain ridge that was covered in snow. I figured the alternator was overcharging the battery, but had no tools with me (DOH! They were back in the trailer!) and didn't know what ELSE to do, so we just turned around and headed back.

Made it back to civilization, but not before the vehicle began shutting down intermittently. (It would lose all electrical power, then shut down.)

I don't understand how the electrical system works. There's a regulator switch, I believe, that's supposed to keep the alternator/generator from overcharging the batteries, right? But if there are TWO batteries, and one's charged but the other isn't, how does the regulator determine whether to continue charging or not? And if it continues allowing the charge, doesn't that cause one to be overcharged?

Please help!

Jen

[BobB]

Please don't mess with the batteries unless you know what you are doing. Batteries can explode! Take the TV to Sears and have the technician check the batteries. You probably need a new one. I'm sure they will be able to figure out how the switch works.

[Harry Young]

When an individual battery cells specific gravity fails because of several reasons "[b]all not good" the cell will boil under any charge, the alternator is most likely not the culprit, if the alternator were it would have to over charge over 14 volts for a long period of time, or the charge regulator is not working right...the charge regulator if solid state and most are today 99.9% of the time usually fail to charge enough. "unless this vehicle is old enough to have a mechanical one" The best guess is the cell is toast, (achedemic argument because boiling batteries at this point are toast) the low specific gravity of the acid to water ratio could be allowing the cells to freeze in cold climates...then put into a charge it will boil in the shorted cell, if the separator plates are damaged it can boil under charge too. [b]Boiling that violently the battery can explode. Living in Alaska in my youth this has happened to me too many times…I have been lucky.

I would stay away, if the battery is done boiling and cool remove it, remove all electrical connections first…isolate the battery in a plastic battery box...test both batteries in a shop. I have had Optima battery returns when the paired batteries are a lead acid battery and a gel cell. If the batteries are good I would look at the series parallel circuit of the set up including the switch.

If you are not mechanically minded and a little seasoned disconnect batteries and take the tug and the trailer to someone who is.

[b]If the battery is still hot...call your emergency number and let the fire boys shut it down and remove it for you.

Above all things recognize this as a potentially lethal situation, it may have explosive consequences, have a water hose near,"for you" and a buddy in the south 40 who can help if something goes wrong or to render medical aide, this is not a time to be alone. Wear clothing easily striped off. (I am serious) A full face shield. Rubber gloves.

Please let the board know what the out come is, this one we may all learn from even if simple or stupid in cause...personally I want to know this one as I am entertaining the idea of dual batteries but will use a battery isolator rather than a switch.



Recognize how close you came, you are lucky and I would hope I am as lucky in that situation when the time comes.

Harry

One of our TVs has a dual battery system involving two 12v Optima batteries. There's a toggle switch that allows us to isolate the batteries from each other or link them (to jump one with the other). This vehicle belonged to (and was set up by) my dad, but he's not doing very well these days, so I'm not sure how much he'll be able to help with the following.

We've had some problems maintaining a charge on one of the batteries. Today, while on a snow run, I noticed an odd sound from under the hood - a very loud bubbling or dripping sound. I opened the hood and immediately spotted the steam drifting out from the battery that was making the bubbling sound.

We were on top of a mountain ridge that was covered in snow. I figured the alternator was overcharging the battery, but had no tools with me (DOH! They were back in the trailer!) and didn't know what ELSE to do, so we just turned around and headed back.

Made it back to civilization, but not before the vehicle began shutting down intermittently. (It would lose all electrical power, then shut down.)

I don't understand how the electrical system works. There's a regulator switch, I believe, that's supposed to keep the alternator/generator from overcharging the batteries, right? But if there are TWO batteries, and one's charged but the other isn't, how does the regulator determine whether to continue charging or not? And if it continues allowing the charge, doesn't that cause one to be overcharged?

Please help!

Jen

[Joe Z]

Harry gives very good advice.......... my friend lost an eye when one exploded in his face. Please Be Careful.
Joe

[Darwin Maring]

You got the best advice one can give from all the above so go to Sears or Advance auto and have them put their battery / alternator machine on your vehicle to check it out.

[Pete Dumbleton]

If you flipped the switch while the engine was running, it's quite possible that damage was done to the alternator/voltage regulator -- They NEED a battery connected to them.

[JenPB]

Thanks, Harry, for the reply. The TV has cooled in the driveway overnight. (It actually FROZE here last night...amazing!) My dad wasn't very happy when I told him about it. Came up with all sorts of hairbrained ideas (like I'd left the welder on...I don't even use the welder and it's hidden in a glovebox where the switch CAN'T accidentally be thrown). He'll come check it out, he said. I'm not certain he'll figure it out since, well, he fixed it last time one of the batteries went dead, and that was about 6 months and a few short miles ago.

I'll keep y'all posted on the outcome.

[Pete Dumbleton]

Two bad batteries? Doesn't sound like an application for $$Optima batteries unless they are within warranty.

[JenPB]

Two bad batteries? Doesn't sound like an application for $Optima batteries unless they are within warranty.

This TV also has some extra equipment that necessitated a second battery, not the least of which is an onboard welder. There's the winch and the water pump for the water heating system (for the shower). So there's a secondary battery to run these items when the vehicle is not under full power. (For example, the welder is typically used when the vehicle is not operational.)

The batteries are arranged in series, but there's a switched isolator. Comes in handy when one of the batteries IS discharged - flip a switch and you can jumpstart yourself anywhere.

[Steve L.]

Hmmm. Batteries in series add their voltages. That would suggest you were getting 24 volts out from the batteries. (12 + 12). Unless, I suppose, the tow's starter and other vehicle requirements are tapped off the first battery and the welder at the "end" of the two batteries in series.

You have a configuration I'm not familiar with, although I'd love to have a look at it... From a bit of distance though... With safety glasses on.

To echo what others have said, battery explosions are not that rare. They don't just spontaneously explode, but during removal, etc. A knowledgeable expert is worth their weight here.

[Dan Meyer]

You may simply have a worn-out battery.

One of the failure modes of a lead-acid battery is the plates inside the battery shed bits of lead, and this lead settles to the bottom of the cell. For the most part, this is no big deal until the end of the life of the batery. At this time, enough lead can be accumulate that it shorts out one of the cells of the battery, and this shorting if the cell will cause a very large current to flow, boiling the electrolyte until the cell is dead.

If you need to learn more about lead acid batteries, http://www.batteryfaq.org/ is a good place to begin.

-- Dan Meyer

[Pete Dumbleton]

My point is that the advantage of an AGM battery is that, while they cost significantly more, they are supposed to last longer and cost less in the long run.

This advantage becomes a monetary disadvantage when there is no long run because they are stolen or in heavy-duty circumstances or whatever...

You might be a lot happier with less expensive, run-of-the-mill flooded lead-acid batteries, although with the welding setup, there may be a need for a rapid-discharge battery string.

Flip the switch when the engine is running and you risk the charging system and then the batteries.

[Darwin Maring]

The problem with this tow vehicle is that it appears to one of a kind, being that a welder located in the glove box and 2each 12V batteries in series is involved and the person that wired it apparently did not include a set of instructions to follow.

[JenPB]

Dad, who was in QUITE a mood initially when I told him about the "boiling" of the spiral batteries (Exide Orbitals, by the way, not Interstate Optimas) mellowed out and offered to come by today to check on the situation. While he was here (in a MUCH better mood) he gave me a tour of the system and showed me what to do "next time."

For those of you who requested further information on the system -
Dual 12 V batteries both attached to an isolator controlled by a dash-mounted switch. Flip switch UP, batteries are parallel allowing the vehicle to jump-start itself and to provide extra power for welder which also has an electrical outlet. In this mode, the generator/alternator charges the secondary (starter) battery first. Flip the switch to the middle and the secondary battery is entirely isolated from the vehicle's system, thereby saving the battery from any drains (radio, shorts, whathaveyou) during long storage periods. In this mode, the alternator/generator charges only the primary battery only. Flip the switch down and the vehicle runs off the primary battery, but the generator/alternator charges the primary battery, then the secondary (starter) battery.

High power generator controlled by a switch on the welder. This was new to me. I saw the switch, but thought it only affected the welder. However, even when the welder is OFF, this switch determines whether the alternator/generator to put out low yield (regular power) or high yield (welding power). Even if the welder is off, if the switch is on high yield, the generator/alternator is putting out extra power all the time, thereby potentially burning up the regulator, the generator/alternator and frying the batteries. (This was set to low yield when the battery boiled.)

Regulator - solid state. Dad said he's heard of them going bad, but in twenty years working with this vehicle and variations of this setup he's never had a problem or SEEN one go bad.

After testing the "boiling" battery - 1 volt today - and the secondary (starter) battery (12.3 volts), we know we'll have to replace one. I wrote to several battery suppliers, and the concensus was that the battery must have had one bad coil. This could have happened in manufacturing, or in jarring - which DOES happen with this vehicle. One bad coil makes for a ruined battery.

Why do I use these batteries? There's "no maintenance" for one thing. No water to top off. I also like the idea that if there's an accident (rollover, particularly) there won't be battery acid all over everything. Further, they're alleged to provide higher cranking power for starting, and, perhaps most importantly for our type of use, maintain a charge longer than traditional lead-acid batteries. We don't drive this TV very often (sometimes don't even start it for a couple of months at a time), so we need that long shelf life. OH...sure, we could DISCONNECT it, but we never MEAN to leave it that long! Something just happens with all our plans when we have little kids milling around the place!

[JenPB]

OH...so what have we done about it? We disconnected the primary battery and now the system is running off the secondary (good) battery. Only the winch remains connected to the dead battery, but since we have to go LOOKING for trouble (ie. snow, mud, rocks) here in California, it's safe to say I won't need a winch anytime soon.

We'll replace the battery, then Dad, the electrical engineer and designer of this system, will walk me through the system while he tests it all out. You bet I'll be writing it all down so I'll know what's what in case he's not available next time something like this comes down. (Or for the next person who acquires this vehicle should it ever change hands.)

[Roger C H]

Reading your post again, I don't know if this applies or not. I ran into this in a motor control circuit I designed with a reversable motor. But it is a good thing to keep in mind.

Hmmm. Does that switch operate a dual relay? If so, you better have both relay operating coils running through the opposite relay side so that you never can get BOTH relays ON. What this does is by running the operating coil for Battery A ON through battery B contol coil, A cannot go ON until B goes OFF and vice versa. Hopefully your relay has small auxillary contacts for this purpose. If not, get one that does.