When is a battery beyond saving?
Discussion
My OH left her car in ign1 for 24 hours, and the battery is now at 5V when disconnected from the car.
I don't have a charger, so before going to buy one I was wondering if there is a critical voltage below which a battery cannot be saved... If so I'll jump straight to a replacement battery.
Battery is standard sealed, not AGM.
ETA There was a pale blue crustiness around the 0v terminal underneath the terminal clamp, if that signifies doom.
I don't have a charger, so before going to buy one I was wondering if there is a critical voltage below which a battery cannot be saved... If so I'll jump straight to a replacement battery.
Battery is standard sealed, not AGM.
ETA There was a pale blue crustiness around the 0v terminal underneath the terminal clamp, if that signifies doom.
Edited by donkmeister on Saturday 4th August 13:42
Car batteries really don't like being deep discharged. Typically, the battery voltage will drop by multiples of 2V as cells fails and short circuit. Even if none of the cells completely failed, being deep discharged will inevitably reduce the charge and current capacity. It may still be adequate to start the vehicle but definitely not as good as new.
In your case where the voltage is down to 5V I'd say it is obviously scrap - it's obviously lost multiple cells. Your chances of getting it back to a nominal 12V are small, and even if you can get all cells to take a charge the current and charge capacity will be a tiny fraction of the new battery performance.
In your case where the voltage is down to 5V I'd say it is obviously scrap - it's obviously lost multiple cells. Your chances of getting it back to a nominal 12V are small, and even if you can get all cells to take a charge the current and charge capacity will be a tiny fraction of the new battery performance.
5v is flatter than a pancake that's been run over by a truck.
It might take a charge, but it definitely won't hold it as well as it used to. You'll probably find it being a bit reluctant come winter, and each time it gets low, it'll hold less afterwards.
For the price of a battery (they really aren't that expensive), I'd just change it. What car?
It might take a charge, but it definitely won't hold it as well as it used to. You'll probably find it being a bit reluctant come winter, and each time it gets low, it'll hold less afterwards.
For the price of a battery (they really aren't that expensive), I'd just change it. What car?
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