Battery acid slushy?

[used red MN]

What does this mean? Battery shows 12.4 volts but I
see a thin layer of ice on the top of the acid? I figured
the charge state would have to be much lower to see
the acid freeze. Sorry do not have a hydrometer.
Battery was in car over night think it got to -10F about
zero now. Battery is out of neighbor ladies car that
would not start. Yesterday afternoon had my 10 amp
charger on it 10 plus hours. But also spent a good 3
hours trying to start it during that time I had my car
hooked to it with jumpers and idling. Took my charger
off of it last night about 9 pm. I had tried to start the
car one last time prior to that with my car jumping it.
Had sat for about 3 hours before that with my charger
on it. Have battery out of car now going to charge it
and take it to the parts store for a check. Do not know
what voltage state was prior to over night period.

 

[Geo-TH,In]

Water has density of 1
H2SO4 has a density of 1.28
Fully charged battery should not freeze.
Google freezing temperatures of battery acid.

Take battery inside, warm it up, charge it, measure specific gravity of acid with hydrometer.

Then measure voltage. Report your findings.

 

[used red MN]

Thanks George! Investigating closer I see a layer of ice over the plates in a few cells. Charging now with 10 amp charger showing 5 amps in 22F garage. Sounds like I should bring it in the basement and let it warm up before charging. Do you think it will off gas much during warm up?

 

[jal-SD]

New batteries can fail & ice in some cells indicates to me a failed battery. As long as it's out, take it to someplace like AutoZone and have it tested.

 

[Janicholson]

With cells showing differences, it is likely toast. I have had charged batteries at 45degrees below work. (the fully charges freezing temp is about -80F they will freeze at about +20 degrees if discharged. Jim

 

[funky_g00]

Get the battery completely thaw then try to charge it. The frozen cells will not take a charge. All wet cell batteries will emit gas when charging but at 10 amps it is minimal. Based on your voltage reading the battery should be able to be saved. I took a 5 year old interstate battery that was frozen solid, let it thaw out and charged it for 24 hrs and used it in my pickup for another 5 years.

 

[rustred]

Showing volts dont mean much. Need to have it load tested once thawed. Pretty sure its done for.

 

[old]

12.4 is a partly discharged battery so it need o be charged up.

 

[used red MN]

Thanks everyone! I will thaw, charge and then get it tested. I know prior to putting my charger on it yesterday it would not light the interior lights and it had set a week or more and it was -20F at one point during that time.

 

[rustred]

so what happened once you hooked car jumpers to it? did it turn over slow? start or what? if her battery is no good your car jumping it might start it but it would draw everything into her battery and just turn it over very slow. experienced this before, and be better off unhooking her battery to start it.

 

[Geo-TH,In]

There isn't one test to tell you everything about a battery,

The voltage alone doesn't mean everything.
The charging rate doesn't mean everything.
Leave charger on until it auto shuts off. Then use a hydrometer,

You can get a very good hydrometer from NAPA with a built in thermometer. If all hydrometer readings aren't the same, a good chance you have a bad cell.
A carbon load tester will also tell you if the battery can produce the amps.
I like using my Midtrontics meter, It measures volts and estimated current capability.
99% of the time the midtrontics meter can tell me instantly if I have a bad cell and the battery is junk.
Some new smart chargers won't charge if you have a bad battery too.
NO battery likes cold temps. The colder it gets the less they like to take a charger.
My car has a built in voltmeter. When I have very cold temps, the alternator will produce 15.5 vdc. Not sure if all cars will produce that high of charging voltage. My car has a huge AGM battery because the engine turns off at stoplights.

Warm your battery, charge it, then after it sits for a day or so, measure with hydrometer and voltmeter.

Measuring voltage as soon as you take it off the charger is meaning less, unless the voltage is below 12v..
All you are doing is measuring surface charge.
I have a carbon load tester, hydrometer and midtrontics volt meter and estimates current amps. I Can't use hydrometer on AGMs

 

[pete 23]

Couple of things I would have to know before making a judgement on that battery. Was this 12.4 volt reading after battery had been standing untouched or was it after you attempted boost or charge.
Actually 12.4 is well over half charged unless one cell is dead. A voltage reading immediately after trying to charge is quite meaningless as even a dead battery will retain a surface voltage reading until it is loaded for a while to remove or left sit undisturbed for several hours.



Next, did you add water to battery at anytime and then not charge or use battery long enough to mix the water with rest of electrolyte. And if all cells show ice trying to charge it is not a good idea until warmed up. More things but that those would come later after knowing these items.

 

[SDE]

I have a charger that will show a percent of total charge. For example. it shows the voltage, and it might show 12.4 and then 20 seconds later it will show 73%. This is on a battery that is sitting on the shelf. Others show 63% after sitting for a month, they are also at 12.4 voltage. Voltage isn't exactly a representation of the power in the battery.

 

[miangus]

Yes, thaw, charge and load test. Never charge or jump a frozen battery. I expect it is junk. Be careful I have had more then one battery explode.

 

[Determined]

Until it is fully thawed it will not take a charge, bigger the battery the longer it will take to thaw out.

48 hours in the basement is good for most.

I had one last winter in a salvage truck I bought about an hour away.

Cold stone dead and swollen.

Boosted truck to get it running and drove it home one hour, even though the truck has a 145 amp alternator after I shut it off not even a dome light would come on.

Pulled battery thawed in basement for 2 days then charged it up.

Used this battery all year in the yard truck and it still started the truck in minus 40 last week.

If the battery is a good one before being discharged and frozen I would say 80% of the time you can save them.

If it was junk before it was frozen 100% of the time it will still be junk.

 

[pete 23]

I do not disagree on the voltage readings showing different state of charge. The thing is it may be 14.41 or 14.49 and the ordinary voltmeter will not show that.

 

[guido]

used red MN,

Simple answer: Water was added and the battery was never charged. Water was on the top of the electrolyte solution, not mix in, that is why it froze,

@ 12.4 volts the battery is at 60% charge, and will usually start the engine. keep in mind that voltage is a potential reading NOT a capacity reading.

Voltage reading under load is what gives you a good battery capacity-state of charge reading,

Guido.