Why is Battery Boiling out Electrolyte?

diyguy

Member
Trying to figure out why my battery is boiling out electrolyte. :?

It's a 2N with a one-wire 6-volt generator. The wiring is clean ... I put a new wiring harness on it shortly after I got it (about 30 yrs ago) so there's no funky wiring. I'm thinkin' the most common causes for this is the cutout relay going bad or the generator adjusted too high. The generator adjustment screw is set on LOW and I haven't touched it for probably 20+ years, so I don't suspect that.

For what it's worth, I recently took the hood off for engine repairs and disconnected much of the the wiring in the process. That makes the timing of this new problem suspicious: it did not boil the battery before pulling the hood and has boiled the battery both times I've used it since putting the hood back on. I **think** I got all the wires back where they belong but now I'm second guessing myself. The wiring is pretty simple ... as best I can tell it's wired according to the standard diagram.

I'm tempted to put a new cutout relay on it to see if the problem goes away since they don't cost much, but would rather troubleshoot than just throw new parts at it.

How would you diagnose this problem and how do you test a cutout relay?

-Steve
 
How much water are you filling the battery cells with? There should be a line marker inside each cell so you don't overfill them -that would cause boiling over. next, I'd suspect the wiring -a 30 year old wiring harness may have seen its day. Once the electrolyte get boiled out, your battery is going to be junk. You can't just add more -chemical reaction with old and new stuff will make it FUBAR. When it did run, was there a charge on the ammeter? You can take the battery, ammeter, cutout, and generator to your local trusty starter/alternator shop and the will bench test it, usually for free. GOOGLE search JMOR's wiring diagrams to find your setup and use it as a guide...report back.

Tim *PloughNman* Daley(MI)
 
On those, the cut out does nothing to regulate the amount of charging.........only the generator HI/LO does that. Cut out connects gen to battery when running and disconnects battery from gen when engine stops turning the generator. Only a simple connect/disconnect. If cut out stuck closed, it would discharge back thru generator & kill battery over a few hours or less. If stuck open, it would never charge battery.
 
Your cut out is not a regulator, just and on/off switch.
If it is charging the cut out is closing. If it doesn't drain
the battery when setting, the cut out is probably opening.

I would double check the wiring since that is the recent change.

Secondary, how old is the battery itself?
Maybe a coincidental failure?
 
Tim, good point about the battery fill level. I did add some water to it while doing the engine repair to bring the level up to where it belongs. I'll have to look again for the fill line but if memory serves I added enough water to bring the level up to the bottom of the tubes that drop down about an inch into the battery case - if that makes sense. The 2 times I used the tractor was for mowing and the run time was about 7 hours total. Even though water boiled out both times the plates are still covered so maybe the battery was overfilled. I have not added more water since the boiling started. The good news is the battery is several years old and I think it's a 3-yr battery so it's near the end of its life anyway.

While running, the ammeter shows a slight charge, maybe, needle just barely to the right of center or maybe right at center. Seems that's about where it always runs ... it doesn't move around much. I'd better take a closer look at that to make sure it's working! Never gave it much thought because it always kept the battery charged so I didn't go looking for a problem there.

-Steve
 
JMOR and Royce, thanks for explaining the cutout ... I didn't completely understand how it worked. My cutout is doing what it should and is not the problem.

I'll re-check the wiring but don't know what kind of wiring problem would do this, especially now that I understand the cutout. The 'ol tractor spends most of its life in a garage and the wiring looks very good with flexible insulation (not brittle).

It's starting to look like battery overfill or maybe it's just reached the end of its normal life.
 
Get a good meter and check the charging rate and charging voltage. Ot take the battery to a shop and have it checked.
 
What's her ammeter say when running?

Start ok?

What's static bat volts after setting 4 hours? Right at shutdown?
 
OKAY -getting some good advice here but understand that when we say check the wiring, we don't mean a visual to see that it is 'not brittle'. You need to follow a systematic, step by step problem solving method to determine the root cause of the issue. Get the correct wiring diagram from JMOR. Trace each and every wire to be sure it is going from point A to point B. Next, GOOD 6 volt AG batteries last on average about 5 years, some longer. You need to get the battery checked UNDER LOAD to see if it is holding a charge. Get the generator checked at the same time. Your trusty local starter/alternator shop can do this usually for free. If the tractor is going to be setting for over 30 days, remove a cable, or better yet remove both and connect battery to a battery tender unit. It sounds to me like it is your battery, but follow the trail downstream to determine that...report back with results so others may learn too.

Tim
 

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