Ramifications Of Frozen Tractor Batteries???

[dpb]

That's an acid solution in there, not water alone...freezing temp is _well_ below 0F.

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[B'razeer Boobar]

Past couple of years I didn't remove the sealed battery from the lawn tractor which is kept in a detached garage. Winter temp in the garage never dropped to 32F due to mild winters. There were no problems the following springs. If the temp does go below 32 for a sustained period, does this necessarily cause irreparable damage to the battery?

[ransley]

If the battery is kept full charged is wont freeze if it goes dead it can freeze, dirt, dust, grease on the battery can discharge a battery, best is remove the positive cable, wash it good with a brush and soapy water and charge it fully.

[Boden]

Until the electrolyte freezes no damage will occur. When it freezes it can cause the case to crack and leak, and possibly damage the interior elements. Battery acid, depending on the state of charge, won't freeze until it drops to -25 to -30 degrees F

[ransley]

A fully charged battery wont freeze until -75 a discharged battery will freeze at 27 and it will sulfate and ruin the battery, with car electronics and dirt on the battery they self dischage so the freeze point goes up.

[EXT]

I have never removed the battery from my lawn tractor which is stored in an out building. I have owned lawn tractors and other battery started garden equipment for over 30 years and never removed batteries and never had a freeze-up nor any damage. Here we can get cold winters in southern Ontario, Canada. Last night was about 0 degrees F. If your temperatures rarely drop below 32 F., you have absolutely nothing to worry about, that is considered a mild day in winter here.

[dpb]

Charged or uncharged doesn't make much difference on the freeze point--certainly not anyways near 32F, anyway...

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[Floyd L. Davidson]

The state of charge makes all the difference. A fully charged lead acid battery is not going to freeze at

-60F, but a totally discharged battery has *water* in it, and will freeze and crack the case at 32F.

[dpb]

I've never seen it happen w/ a small engine battery even outside over winter in W KS where 0F and below are common -- they're invariably discharged by spring as I don't really worry about them and I've never had a problem w/ one, sealed or no...the specific gravity changes, sure, but never to the point ime of becoming "water" at 32F (or even very close)...

[S. Barker]

a dead battery does IN FACT have just water in it and WILL freeze at 32 degrees. There's no disputing this. BUT, whether or not it actually damages the battery is the variable. Some batteries will tolerate this more than others. What happens is when the WATER freezes, it expands and damages the lead plates. Some have more room to move than others and will survive. Most decent quality batteries will be damaged by freezing due to the closeness of the plates. BULGING ends on the battery itself is a telltale sign that it has froze at some point.

s

[Twayne]

Well, not at 32f because of the mix and impurities, but the temp starts getting dangerous to batteries at some point not too far below 30F. If you've ever noticed, the liquid in a cold, discharged battery will turn to slush first when it freezes, and continually become more solid as the temp drops.

Typically, it's best to charge batteries monthly, especially if they're exposed to the elements. Besides their internal rate of discharge, a nice cold battery with dew/moisture on it can also find external paths to discharge through. As a battery discharges it becomes more and more susceptible to freezing. Even with slush, if pressure builds up between the plates and moves them at all, added to the normal sulfation of not being kept charged, they can then take a quick nosedive to dead, becoming nothing but a resistor and capacitor. I keep my batteries in the garage and periodically charge them whenever the mood hits me; seems to work well. Usually I'll hold a headlight on the posts for a minute or so, just to bring it down a bit, so it'll charge at a higher rate. Theory is, it helps the sulfate situation, but who knows? You used to be able to "shock" such lead acid batteries back to another season's use sometimes, but the last couple times I tried it, it didn't work. The ability must have gone away with all the design "improvements" in batteries.

My 2 ¢ anyway.

Twayne

[Floyd L. Davidson]

They are not nearly as discharged as you think then.

As I said, a "totally discharged battery" has *water* in it, not acid, and it freezes at 32F. But you'd have to make a real effort to accomplish that too, and instead there is almost always some acid, and the freeze point is below 32F.

I've seen *lots* of batteries that have frozen and cracked the cases. But if you live where it actually does get cold, the battery doesn't have to be all that discharged either... :-)

[Twayne]

The freeze points are low, but ... they aren't consistant and outside a lab I've never seen finite figures, only empiracal data. It depends on too many things to state that a battery won't freeze until -xx degrees. Every battery, especially from Mfr to Mfr, and depending on age/prior use has different specs. It does seem pretty sure though that most good batteries will last to below at least -30, often considerable lower.

[Floyd L. Davidson]

The mix is *water*, if it is discharged. The water is distilled water. As a result the actual freeze point would indeed be very close to 32F.

That is true with just about *any* liquid that freezes.

Or bettery yet, put them on a float charge, continuously.

Not likely to be significant.

If it is only slush, there is no problem, and it will not put pressure on the plates.

Actually I doubt that pressure on the plates is ever much of a problem, due to the internal geometry. The problem is pressure on the sides of the case, which will crack.

[HeyBub]

I dispute it. A fully-charged battery will freeze at about -92 F, a completely discharged battery freezes at -16F.

[dpb]

Care to try a drink of the remaining fluid as a test? :)

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[Pat]

Don't know about your tractor, but I know that a couple of years ago I stopped removing the battery from my car every night. It was getting to be a pain. I mean, who wants to go out at -40F and put your battery into your car before you start it. It's a real pain. Now I just leave it in and it seems fine. It hasn't frozen yet.

Since your tractor battery is about the same as your car battery, I'd only remove it if you're also removing your car battery.

[Twayne]

Actually, the small lawn tractor batteries in general are and are far from as reiably or structurally sound as a car battery. If you don't buy a branded, top line brand of lawn tractor battery, you're likely to see it last over about two winters before it begins to have a large internal resistance which won't allow it to store enough energy to start the engine any longer. Without care, cleaning and a charge prior to storage, many of them won't even make it thru one sub-zero winter stored outdoors. Crank-amps is a number you don't find on them for a reason; they're variable. A-H is reasonable for comparison purposes, but, once past the infant mortality stages, the cheap ones go south pretty quickly. There are a lot of reasons for it, most of which equate to cheap internals. Thinner plates, different acids, longer times spent on the shelf (which is nearly irrelevant to a car battery), unclean water, several impurities from the Mfg process itself and probably a lot of other things I'm not aware of. It's just a cheaper process using cheaper materials. Around here, Exide makes about the longest lasting equipment batteries; they seem to be as good as a car battery, but they are costly compared to what you find at the big box stores, who will buy all kinds of trash just to get them cheap sometimes.

My 2¢ again,

Twayne

[bud--]

My understanding of car batteries is: Charged car batteries have lead oxide positive plates and lead negative plates. When discharging both plates move to lead sulfate. Taking the sulfate out of sulfuric acid leaves hydrogen which combines with oxygen from lead oxide to form water. Whether the electrolyte turns to pure water in a *completely* discharged battery depends on whether the reaction is limited by availability of lead/lead oxide or availability of sulfuric acid. A completely discharged battery could have acid left but only lead sulfide accessible on one of the plates. But most (or all?) of the sulfuric acid becomes water. And I agree state of charge makes a big difference.