How long is too long for a dead car battery

In summary, a deep cycle battery will not last as long as a regular lead acid battery when not being charged or left discharged.
  • #1
John1397
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18
I have or had two good car batteries one was a deep cycle they were connected to a 20 Ma led it could have been as long as four months since solar charger stopped working on top of that they were outside in temperatures as low as minus 25 degrees fahrenheit, what I want to know if one took a new battery and did this to it can it be brought back to make work as a battery should or does this cause a battery to completely fail. I had these batteries on a 30 amp charger for 10 minutes but they do not take much of charge only four amps for two batteries is not much for dead batteries usually when you crank a vehicle a long time and run battery down and hook them to a charger they will draw at least 10 amps each. I do not know if the acid can freeze in a dead battery these do not leak.
 
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  • #2
John1397 said:
I do not know if the acid can freeze in a dead battery these do not leak.
Honestly, I’ve tried something similar to this where I put a rechargeable dead battery in the freezer just as an experiment. It’s either it was already really bad or my test results are correct but the battery (even after charging it) would not work. I’m assuming that the acid in the battery has in fact frozen but I will never be sure if that actually happened because I never opened it. I’m not an expert with cars (I’d say that fishing reels are more of my thing) but that’s as much info as I can give you. Hopefully that helped even with my lack of knowledge.
 
  • #3
A low temperature will lower the battery capacity temporarily. It will need to be recharged.

When a car battery is left discharged for a long period, the plates become sulphated and the internal resistance rises. This is a most common failure mode. Calcium batteries are less susceptible to this problem.

It may be possible to recover the battery by charging it slowly over a few days, then holding it at over 15 volts for some time. It will gas but the higher voltage will strip the sulphate from the plates. If the battery is a gel cell or is a sealed battery you should not attempt to overcharge it. Low temperatures slow the rates of reaction. Do not attempt to charge a frozen battery.
 
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  • #4
I should mention the battery still had 10.5 volts maybe not frozen seems like if you were testing a frozen battery it would be 0 volts.
 
  • #5
My guess is they will have lost capacity.

Back in the 1980s I started using lead acid batteries to charge model aircraft batteries. I found that my lead acid batteries were lasting only 6 month after which the capacity had fallen too much.

The problem was traced to me leaving them partly discharged during the week. I switched to recharging them ASAP after use and keeping them on a float charger when not in use. Now they last 4 or 5 times longer.
 
  • #6
John1397 said:
I should mention the battery still had 10.5 volts maybe not frozen seems like if you were testing a frozen battery it would be 0 volts.

That sounds like one cell is completely dead.
 
  • #7
John1397 said:
I do not know if the acid can freeze in a dead battery these do not leak.
A frozen battery can burst the casing, causing leaking fluid when warmed up.
A frozen battery can have the plates pushed against one another, effectively shorting a cell.
A dead battery can freeze at the same temperature as water.
A full battery will freeze at a much lower temperature, around -70F I think.
 
  • #8
Baluncore said:
Do not attempt to charge a frozen battery.
I never knew it could blow apart from gas formation.
Good to know.
 
  • #9
CWatters said:
My guess is they will have lost capacity.

Back in the 1980s I started using lead acid batteries to charge model aircraft batteries. I found that my lead acid batteries were lasting only 6 month after which the capacity had fallen too much.

The problem was traced to me leaving them partly discharged during the week. I switched to recharging them ASAP after use and keeping them on a float charger when not in use. Now they last 4 or 5 times longer.
here's a funny story.
We had a Cockshut tractor that was used intermittently in the warmer months.( front end loader )
The battery was never left on a trickle charge when not in use, and was stored in a non-heated garage over the winter.
To start the thing up, the battery was put on a charger, then attached to the cables, and never failed to give the old girl a go.
I do not recall ever my father having to buy another battery for that machine.
6 v battery if I recall correctly.
http://2.bp.blogspot.com/-6-Ec36DZfEc/TbY7WJMQI5I/AAAAAAAAAMU/b772S55PRXk/s1600/100_9560.JPG
100_9560.jpg


Not quite as rusty as that, although the paint was faded.
It had a PTO and the thing sticking out is for a belt drive - good for running the wood saw.
The belt had to have a twist put in it, else the saw would would run backwards.

One autumn, harvesting, going down a hill, with a load of grain in the trailer, the bearing on the rear wheel went.
Nice feeling going down a hill with a screeching wobbly rear wheel and 10t load pushing you down. You just can't stop.
We had to take a half day off to pull the wheel off, run into town for a bearing ( yes they were stocked , not a 2 day wait, so much for progress )
Re-assemble and back to the harvest.

so much for the reminiscing, but,
I do wonder if that battery would still be in, or could still be put into operation.
Tractor probably not as the HP is enough to cut it these days.
 

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  • #10
256bits said:
The belt had to have a twist put in it, else the saw would would run backwards.
The reason for the twist is to make the alignment of the crowned pulleys less critical. The twist also prevents bouncing and wears both sides of the belt. To reverse the drive you could simply face the tractor or saw bench the other way. Even though the old steam engines could run backward as easily as forward, they were always used with a twist in the belt.
A mobius belt, built with a half twist, does not bounce, wears evenly on both sides and can drive in either direction with the same amount of twist.
 
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  • #11
Baluncore said:
The reason for the twist is to make the alignment of the crowned pulleys less critical. The twist also prevents bouncing and wears both sides of the belt. To reverse the drive you could simply face the tractor or saw bench the other way. Even though the old steam engines could run backward as easily as forward, they were always used with a twist in the belt.
A mobius belt, built with a half twist, does not bounce, wears evenly on both sides and can drive in either direction with the same amount of twist.
Ok That's so true and sensible now.
Especially the bounce from variable torque.
Makes me wonder who really figured these things out years ago, and how - trail and error - mis-assembly that wound up working better than the supposedly natural way one would do it. Even the crown on the pulley doesn't seem correct at first inspection. Names and dates are all lost in history.
 
  • #12
Buy a charger from Walmart ( may need to order only be) with a battery rejuvenation (desulfation) function. Black and Decker (otherwise total Junk, Inc) suppliers them. Desulfation 24hrs per week of disuse, then recharge normally for three days. Worked for me with old lead-acid forklift batteries
 
  • #13
256bits said:
Names and dates are all lost in history.
“In 1828 in Lowell, Massachusetts, Paul Moody substituted leather belting for metal gearing to transfer power from the main shaft running from a water wheel. This innovation quickly spread in the U.S.
Flat belt drive systems became popular in the UK from the 1870s, ...”
See; https://en.wikipedia.org/wiki/Line_shaft#History
 
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Related to How long is too long for a dead car battery

1. How long does a car battery typically last?

On average, a car battery will last between 3-5 years. However, this can vary depending on usage and maintenance.

2. How long can a car battery sit unused before it dies?

A car battery can typically sit unused for 2-3 weeks before it starts to lose charge. However, this can also vary depending on the age and condition of the battery.

3. How long does it take for a dead car battery to recharge?

The time it takes for a dead car battery to recharge can vary depending on the type of battery and charging method. On average, it can take 4-24 hours to fully recharge a dead car battery.

4. How can I tell if my car battery is dead?

If your car battery is dead, your car will not start and you may hear a clicking sound when you turn the key. You can also use a voltmeter to check the voltage of the battery; a fully charged battery should have a voltage of around 12.6 volts.

5. How long is too long for a dead car battery?

If a car battery has been dead for several months or more, it is likely that it will not be able to hold a charge and will need to be replaced. It is generally recommended to replace a car battery if it has been dead for more than 3 months.

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