I have a frozen maintenance free battery with a life of 14.5% life according to my dashboard display. I really can't afford to replace it at this point. I had it boosted and let it run for a half hour or so. I tried it the next day and it was dead again. Is there any way to fix it? I live in Calgary Alberta, Canada and we've just come out of a cold snap. Temperatures have been -32 and below at night for the last week or so.

  • I would strongly warn anyone about to jump start or charge a frozen battery. The charging causes the battery to produce gasses. If there is a layer of ice in the battery, the gas cannot vent out of the case. The gas can become pressurized. The pressure can become high enough to cause the case to burst. Especially a case that has been weakened by distortion from the expanding ice. – mikes Jan 21 '20 at 21:29

No there is no way to bring a battery back to life after it have died,when a battery have been frozen it is not a lot you can do it will be chemicaly and mecanically degraded.

The best way to avoid a battery freezing is to keep it well charged(the freezing point of a fully charged battery is -70C and a 50% charged battery it is less than -30C).

The only thing you can do now is to replace the battery.

a maintenance free battery have not yet been invented so the marketing of this is misleading,but there is a lot of low maintenance batteries out there.

To make a lead acid battery last for a long time you need to be sure it never gets below 60-70% of the rated capasity for any lenght of time,and be sure to fully charge the battery as soon as possible if it have been low on charge.

If you top off your battery by fully charging it once a month you will extend the life significantly,the longest living car battery i have had died at 21 years two months,it was a standard lead acid battery 75AH.

It is best to remove the battery from the car or be sure it is at room temparature when you put your charger on it,the ideal temparature is about 20C for charging a battery.

  • 1
    Could you elaborate on what you mean by a maintenance free battery have not yet been invented? If you put a battery in a vehicle and do nothing with it until you replace it 5 years later (the end of its useful life) ... that seems to me to be as "maintenance free" as something can get. – Pᴀᴜʟsᴛᴇʀ2 Jan 21 '20 at 13:23
  • if you do not keep an eye on the charge of the battery it will fail well before it is five years old,every time you start your car you will recharge it if you just let the battery sit whitout charging it it will fail sooner than if you keep it charged.so if you just put it in your car and forget it you are wasting money and could as well buy a lower cost battery that needs to be maintained by replacing the water that is lost by normal use,the lifetime of the two is the same if you let them run out of charge so both need some looking after. – trond hansen Jan 22 '20 at 8:00
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    Typically, for batteries, when it is stated as "maintenance free" it is meaning you don't have to mess with refilling the cells with deionized water. If the battery is used as it is supposed to be, the maintenance you are talking about happens automatically without user intervention ... that's how it is maintenance free. I do, however, take your point. – Pᴀᴜʟsᴛᴇʀ2 Jan 22 '20 at 17:46

As per the other answer, when a battery is toast, it's toast. Dubious claims of devices that can revive them should probably be disregarded and I any case those devices usually cost the same as a new battery. Have you tried getting a second hand battery from an auto wrecker? It should cost less and be more usable than the one you have

If you want to do anything with your existing battery you'll need to unfreeze it; remove it from the car and take it inside. Charge it with a trickle charger of less than 4 amps (preferably around 1 amp) - it will take a long time to charge. A 70ah battery would conceptually take 70h to charge at a rate of 1 amp (though they never get so low as to be at 0% capacity without getting ruined too) - if your car is saying 15% then it should take at least a couple of days to fully charge at 1a. If it charges faster than this it has a reduced capacity to hold a charge. If it charges really quickly, it's shot - massively degraded capacity

If you can get a reasonable amount of charge into it slowly (boosters and driving round doesn't do a dead battery any favors; slamming charge into them buckles the plates causing internal shorts and diminished capacity. It's also not enough to jump start it and run the engine for half an hour) it may start the car. In the cold the engine is much harder to turn and the battery (being a chemical reaction) just doesn't provide as much power when it's really cold. As such you'd do better to keep charging on the battery (put it on charge every night overnight) and keep the battery warmer by putting a blanket around it; even consider wiring up a heat mat (like toe things they use to keep lizards warm) under it overnight

As noted, if it's too far gone it won't provide enough amps to start the car. If your car is a stick shift then you might have some success in parking on a hill and bump starting instead of using the starter

But all in, for the messing around this is I think you'll pretty quickly look to source another battery!

  • One thing ... in newer cars, if the battery is drained enough to not have enough energy to provide a reference to the field, you will not get a car started even with running it down the hill. The alternator will not have anything to excite it and thus will not provide anything to get the car started. Ask me how I know ... ;-) – Pᴀᴜʟsᴛᴇʀ2 Jan 22 '20 at 18:01
  • Good point that! – Caius Jard Jan 22 '20 at 19:31

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