Weeping battery

[ruffdog]

I would never keep a weeping battery in anything...you get what you pay for. Many times they mount the batteries in front of the radiator, fan and coolers so if the battery is venting, any acid will be pulled right through them. It is a real mess dealing with long term acid damage on any vehicle or equipment.

 

[5030]

If it's an old style inexpensive battery with those six caps on top for checking the specific gravity and adding water...well, there's a reason those old style batteries are inexpensive. Mine always corroded the battery terminals and battery box. Vibration and rough country make it worse, but nothing makes it not happen.
Except: next time buy a sealed AGM type battery. It costs about 30% more than the old wet cell type but does not leak anything or corrode anything.

Not exactly. AGM's are vented to the atmosphere as well. They are NOT sealed. Only ones that are sealed are stratified electrolyte batteries like The Hawker or a LiPo battery

 

[5030]

If a flooded cell is leaking, you have an issue with voltage regulation, not the battery. It's gassing off from over charging.

 

[rv7charlie]

AGM (Absorbent Glass Mat) batteries that I've worked with (for almost 30 years) are indeed sealed, with what amounts to a 'popoff' valve which only opens if the battery is abused by overcharging, causing gas buildup at a faster rate than it can be reabsorbed (see 'absorbent' in the name). One of their alternate names is 'SLA', for Sealed Lead Acid. Yet another name is 'VRLA' for Valve Regulated Lead Acid. Here's some reading on the subject.

I'd agree that one possibility is overcharging, but that's simple to check. Just run the tractor at normal operating rpm and measure voltage across the battery terminals; it should be at least 13.8 Volts (barely adequate) but no more than ~14.7 Volts (a bit high for a 'wet cell' battery but tolerable). The SLA batteries actually like charge voltage on the higher end of the range; wet cells seem to prefer around 14.2-14.4 volts.

I'd think that operation (bouncing, tilting) should be a minimal risk, unless the battery is a truly terrible design or was designed for stationary use, like battery backup for a solar system. I replaced the 15+ year old wet cell battery in my Kubota 4700 a couple of years ago with another big wet cell tractor battery, and neither has ever spilled acid, even though I am not kind to the tractor. ;-)

If the old one wasn't spilling acid and charge voltage checks ok, there's a fair chance that the battery is just defective or damaged. I've had one SLA battery in an aircraft that I discovered leaking after a few months of use; turned out to have a pinhole in the side of the case. Likely shipping damage that I didn't notice when I installed it.

 

[5030]

with what amounts to a 'popoff' valve which only opens if the battery is abused by overcharging, causing gas buildup at a faster rate than it can be reabsorbed

Which is exactly what overcharging does, it causes the jar to gas off and emit corrosive gas which eats stuff up like the battery tray for instance. I believe the OP has a bad voltage regulator or an alternator issue and not correcting that will only result in more off gassing, corrosion and other damaging effects.

Myself, never been all that impressed with AGM batteries. Guess they have their place, just not at my place.

 

[rv7charlie]

That's why we can still buy either one. ;-)
One big upside for some of us (beyond the sealed, mount in any position feature) is that their self-discharge rate is much slower than wet cell batteries. A wet cell can lose over 10% of stored energy per month, just sitting, through self-discharge. SLAs can sit for a year and only lose 10-15% of their stored energy. For stuff that doesn't get used much, it's a life (battery) saving feature.

They're a bit lighter too, though that might even be a disadvantage in farm equipment. As I said in my earlier post, I replaced the wet cell version in my Kubota tractor with another wet cell. But you'll never see a wet cell battery in my airplane, even though they're still available.

 

[TT45]

AGM (Absorbent Glass Mat) batteries that I've worked with (for almost 30 years) are indeed sealed, with what amounts to a 'popoff' valve which only opens if the battery is abused by overcharging, causing gas buildup at a faster rate than it can be reabsorbed (see 'absorbent' in the name). One of their alternate names is 'SLA', for Sealed Lead Acid. Yet another name is 'VRLA' for Valve Regulated Lead Acid. Here's some reading on the subject.

I'd agree that one possibility is overcharging, but that's simple to check. Just run the tractor at normal operating rpm and measure voltage across the battery terminals; it should be at least 13.8 Volts (barely adequate) but no more than ~14.7 Volts (a bit high for a 'wet cell' battery but tolerable). The SLA batteries actually like charge voltage on the higher end of the range; wet cells seem to prefer around 14.2-14.4 volts.

I'd think that operation (bouncing, tilting) should be a minimal risk, unless the battery is a truly terrible design or was designed for stationary use, like battery backup for a solar system. I replaced the 15+ year old wet cell battery in my Kubota 4700 a couple of years ago with another big wet cell tractor battery, and neither has ever spilled acid, even though I am not kind to the tractor. ;-)

If the old one wasn't spilling acid and charge voltage checks ok, there's a fair chance that the battery is just defective or damaged. I've had one SLA battery in an aircraft that I discovered leaking after a few months of use; turned out to have a pinhole in the side of the case. Likely shipping damage that I didn't notice when I installed it.

Seeing as you seem to have some expertise in this subject, I have a similar issue to throw in.

My 75 MF 265 is running 14.75 v when full charge. How to tweek down the voltage to keep from damaging SLA battery? Renew the internal regulator in my Delco Alternator or add-on some resistance like lights on?
I think this alternator also has some very small parasitic drain.

 

[rv7charlie]

If you're using an SLA, you're probably fine. SLAs actually are happier with higher charge voltage than wet cells. A read through the Odyssey owner's manual and other docs would probably be helpful. Most of the SLA starting batteries use similar chemistry, so the well-written Odyssey docs are widely applicable.

I doubt there's any voltage adjustment on the MF's regulator. Given the year, it might have an external regulator or it could be an internally regulated, 'one wire' alternator. If it's external regulated, just about any automotive regulator for late '60s-early '70s cars should work as a replacement; the Ford model works on most externally regulated alts. A quick googling indicates it is probably internally regulated, which reduces the odds of it being adjustable, but also reduces the cost of replacement of the regulator, if you can do it yourself. Swapping the regulator isn't difficult, but you would probably have to disassemble the alt to do it. Reassembly typically requires 'pinning' the brushes in the housing (holes in the housing are provided) while the armature is reinserted in the rear case half.

The alt *should* be out of the circuit when the tractor's switch is off. If it's an internally regulated model and the B-lead does (by design) remain connected to the battery and it is draining the battery, that's a good indication that you have issues with either the regulator or the diode block inside the alternator.

 

[big bubba]

the tractor alternator checks out normal charge 14.5 v @ idle, so the primitive battery is the culprit. the previous factory one was "sealed" cells. never ran into this prob before on equip, maybe a heads up for those looking to replace with cheap removable plate type.
note that i did remove fluid from cells when this 1st occurred, but the prob continued... thx for all the input.

 

[rv7charlie]

You're probably good to go with the charging system, but it's a simple thing to check at normal operating rpm. If the regulator does by some chance have an issue, voltage may look normal at idle but rise as rpm goes up and the alternator can produce more output. That would be 'normal behavior' if the regulator wasn't regulating; at low rpm some alts can barely keep up with electrical demand so the voltage would be limited by electrical load until rpms come up, and with the rpm increase, voltage would increase.