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Why is my battery bubbling?

bp71k5

bp71k5

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Reading the talk about different batteries reminded me of another problem ive been ignoring. After driving the truck for a bit and then shutting it off, I can hear what sounds like boiling/bubbling inside the battery for a little while. The other problem is that in Moab, something must have got jostled around because i can see that battery acid has spilled and ate the paint off my frame under the battery.

It's just a cheap parts store battery that's about 6 years old. It still starts just fine though. Is the bubbling and leaking a sign of a big problem or just because it's old?
 
Iirc, it's a sign of being over charged.
 
nvrenuf said:
Iirc, it's a sign of being over charged.
Click to expand...

Hmm, doesn't that point to a faulty voltage regulator? The alternator is fairly new and my voltage gauge reads about 14v most of the time, a little less when I have lots of electrical items turned on.
 
Most times it is caused by an over charging alternator which yes is controlled by the regulator. You might have an intermitten problem though and that would be more difficult to find. It is entirely possible that one of the plates in the battery has shorted and is causing this as well. Voltage should be anywhere between 13.5-14.5 typically.
 
4X4HIGH said:
Voltage should be anywhere between 13.5-14.5 typically.
Click to expand...

Yea, that's about where it reads all the time. I did convert the wiring over from the original externally regulated alternator to use a 105 amp 12si. I am pretty confident it hooked up correctly since it charges about 14.4v, but you never know. And the battery is at least 6 years old, it came with the truck when I bought it so I don't know the actual age. It could be 7+. Ive also never added water to it.:doah:

Sounds like I should start with a new battery and then keep an eye on the charging voltage.
 
bp71k5 said:
Yea, that's about where it reads all the time. I did convert the wiring over from the original externally regulated alternator to use a 105 amp 12si. I am pretty confident it hooked up correctly since it charges about 14.4v, but you never know. And the battery is at least 6 years old, it came with the truck when I bought it so I don't know the actual age. It could be 7+. Ive also never added water to it.:doah:

Sounds like I should start with a new battery and then keep an eye on the charging voltage.
Click to expand...

Brian, most "generic brand" batteries usually start to go south after about 3 years and at 6 or more years it is just time to replace your battery. Unless you want a dry cell battery I would suggest you pick up an Interstate battery. I've been running them for years without any issues and my current Interstates in my rig are now 9 years old and still going strong. I can probably get you a good price on one if you decide to go with Interstate.
 
it's the battery sulfating.... it happens most of the time after topping off with water, or too low on water.. it can be a bad cell, usually that is indicated by just some of the cells sulfating.. if all of them, it's usually an overcharging issue... as mentioned, 13.7 to 14.3
 
If the battery is actually being overcharged, its fairly urgent. I would have to check the schematic on your voltmeter, but I don't know of a way the battery could be seeing a different voltage from the meter.
But, even so, if you have a separate voltmeter, it would not hurt to check the voltage At The Battery when the engine is above fast idle with everything electrical turned off.

Otherwise, its most likely the battery.
 
bp71k5 said:
Thanks fellas! Scott, this is not an urgent item to fix but I will give you a ring when it is. :thumb:
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If it's a wet battery and you can pop the covers off, try and check which one is bubling.
If they all are bubbling slightly it's OK, if one is bubbling excessivle, it's a bad cell and you will be stranded sometime.
WHat could have happened is you spilled some of the acid and now a plate is exposed and is damaged, and sometimes even after you added the water it's FUBARED.
If you are not having issues starting now in the cold, it means you probably have only one cell and your engine is not to tight.
I would have the charging system checked, and a new battery put in.
I got tired of jumping cars so that's how I think now.:waytogo:
 
most store bought batteries will last a few years and over time loses the sulferic acidity and will cause the battery to boil out the water in the battery easier over time.even if the battery holds a charge i would replace it.sounds like it is just old and in need of a replacement.i wouldnt try and add water to it.and make sure you clean up the acid that has already been pushed out of the battery.it will eat through paint and weaken the metal it comes in contact with.over 40 years mine is completly eaten through the inner wheel well and battery tray.not just rust because the drivers side is still intact.anything over 14.5 will boil a battery also.just too high a voltage will cause excessive heat in the battery.
 
The truck isn't being driven right now for other reasons, that's what I meant about it not being urgent. Itll be another month before I turn the motor on again.
 
Back looking for a battery. I had some acid spill out during moab (bumpy trails I guess?), so it seems like agm would be a good choice, but I'm hesitant to go with optima. Is odessy the only other option or is agm not going to be good for a truck that sits for months at a time?

Edit: I'm looking at a lead acid interstate megatron or a carquest ngt extreme agm battery. Only reason I'm considering agm is to fix my battery acid spilling. I'm not sure whether the spilling is from vibration, or just from being too old.
 
A 12V battery wants to charge at about 13.5V. When one cell goes bad, it becomes more like a 10V battery, which would want to charge at about 11.3V. So a normal alternator now becomes a serious overcharging condition. A bad cell is easy to test for. Just turn off the engine and leave the headlights on. If the voltage drops below 12 before a few minutes has gone by, replace it. Don't go off of just the dash gauge though. Put a real meter on the battery while it's charging.
 
Blue85 said:
A 12V battery wants to charge at about 13.5V. When one cell goes bad, it becomes more like a 10V battery, which would want to charge at about 11.3V. So a normal alternator now becomes a serious overcharging condition. A bad cell is easy to test for. Just turn off the engine and leave the headlights on. If the voltage drops below 12 before a few minutes has gone by, replace it. Don't go off of just the dash gauge though. Put a real meter on the battery while it's charging.
Click to expand...

I'll try testing it just cause I'm curious, but I bought a new battery today. I found a date code for this old one and it was manufactured in 2003. So it lasted 8 years and still starts the truck just fine. I just didn't want to chance it after the bubbling and acid spilling. Hopefully this new AGM will be ok.
 
Get yourself an acurate voltmeter, and check the voltage at the battery with the truck running at fast idle or a little faster.
With the battery charged, it should be in the range of 14.5 max.
13.5-14.5 is ok. Between those two usually just means that the battery is charging and loading the alt down.

The important thing is, not to go over 14.5. That will burn a battery up, and you do not want to do that to your new AGM.

If you have a voltmeter in your dash, you can compare its reading to the known good one.
That way, even if its off, you will know where it is reading when the battery is seeing max safe voltage.
If it goes over that mark, check with the good meter.
 
Ok, I took some measurements this morning. It hasn't been started in a week so I expect the battery to not be fully charged.

Cold engine(off), voltage between battery posts = 12.07 volts

Start engine, slightly fast idle(900 rpm max) voltage between battery posts = 14.7 volts

Engine running, voltage from alternator at junction block = 14.8v

Engine running, voltage reading on the in-dash meter = 15.0V

Do I need a new alternator? I've seen the volt meter in the dash hit 15 before but not for long, usually happened in the morning which I just attributed to a low battery, but now I'm thinking different.
 
Also tried the headlight measurement a well. Starting at 12.07 volts, the voltage dropped slowly to 11.60 volts over the course of a minute and then stayed there for another minute before I shut the lights off.
 
From that info your alternator is fine. Anything between 13.5-15.5 is normal with about 14.5 being average.
 
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