I had to replace my battery today... you'd think they would make it easier on these new cars ffs... Anyways it got me thinkng. Theres sulferic acid which plates lead on the metal in the acid... if the battery is totally dead... which i would assume that is because the metal in the acid is completely corroded with lead, thus no reaction is possible... Is the acid in the battery still powerful? I've read its 30-50% pure
Dead car battery
- Thread starter Akragon
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It can be tested I guess, but better get new battery acid if possible.
no... i want the acid in the battery. I already got a new one for the stupid 4cyc suv lol
i figure IF i filter it... and maybe heat er up a bit i could purify it
That is what I said, get a few liters of fresh battery acid.
You will have no idea on the status of the acid in old batteries.
At least if reagent quality is of concern.
Oh sorry... how do you test Sulfuric acid for purity... few drips on a paper towel?
No wait... we're talkin about acid from a dead car battery... Do you think its still 30ish %? or has it probably been lowered over the years of use...
I don’t know, but there must be tests, titrations of some kind.
There is no way to know unless you know age and real reason for why it died.
There are optical tests instruments for battery acid strength, but it don’t say anything of purity.
In a fully charged lead acid battery from your old pickup truck, with good lead plates (electrodes), the electrolyte is around 38% H2SO4 and around 62% H2Oper cell, the acidic electrolyte at this concentration of acid the specific gravity will be about 1.28 for each of the (2-volt cell) of the battery of cells.
As the battery discharges under a load the specific gravity of the acid as well as the concentration of acid changes to water as the cell discharge water from the original electrolyte and water from the chemical reactions involved.
on the discharge of the cell (6 cells in a 12volt), the electrode anodes of the pure spongy lead in the cell are converted to lead sulfate, and the cathode electrodes of lead peroxide PbO2 also convert into lead sulfate lowering acid concentration and specific gravity of the solution more towards the specific gravity of water alone.
As the cell is charged the specific gravity raises back to around 1.28
0r 37%H2SO4 62% H2O for that volume of electrolyte.
a cell fully charged will have a specific gravity of about 1.28
a cell with a 70% charge will have a specific gravity of about 1.22
a cell with a 50% charge will have a specific gravity of about 1.17
a cell with a 30% charge will have a specific gravity of about 1.12
a cell with a 10% charge will have a specific gravity of about 1.07
a totally dead cell electrolyte will just be water sp. gr. 1.00
a bad cell can develop a hard sulfate, or plates can sort out, or break lowering the sp. gr. and that cell's ability to charge, this cell will have a different specific gravity from the other 5 cells in the battery.
so even most "Dead batteries may still have a good portion of the dilute acid if those cells will still hold an electric charge at the electrodes.
So charging the old battery before recovering any acid, the better the condition of the cell the more charged the more acid in volume and concentration you could recover.
Evaporation can be used to concentrate the acidic water up to its azeotrope of 98% concentration by evaporating off water from the much less volatile sulfuric acid.
The automotive store will have a very cheap pipette with floating balls to get a good idea of specific gravity for this range, you can get a higher dollar or better tools to test (concentration of acid to water) or specific gravity and in wider ranges...
edited (Change number cells, my eye sight cannot tell 6 from9 at a black wore out old keyboard)
As the battery discharges under a load the specific gravity of the acid as well as the concentration of acid changes to water as the cell discharge water from the original electrolyte and water from the chemical reactions involved.
on the discharge of the cell (6 cells in a 12volt), the electrode anodes of the pure spongy lead in the cell are converted to lead sulfate, and the cathode electrodes of lead peroxide PbO2 also convert into lead sulfate lowering acid concentration and specific gravity of the solution more towards the specific gravity of water alone.
As the cell is charged the specific gravity raises back to around 1.28
0r 37%H2SO4 62% H2O for that volume of electrolyte.
a cell fully charged will have a specific gravity of about 1.28
a cell with a 70% charge will have a specific gravity of about 1.22
a cell with a 50% charge will have a specific gravity of about 1.17
a cell with a 30% charge will have a specific gravity of about 1.12
a cell with a 10% charge will have a specific gravity of about 1.07
a totally dead cell electrolyte will just be water sp. gr. 1.00
a bad cell can develop a hard sulfate, or plates can sort out, or break lowering the sp. gr. and that cell's ability to charge, this cell will have a different specific gravity from the other 5 cells in the battery.
so even most "Dead batteries may still have a good portion of the dilute acid if those cells will still hold an electric charge at the electrodes.
So charging the old battery before recovering any acid, the better the condition of the cell the more charged the more acid in volume and concentration you could recover.
Evaporation can be used to concentrate the acidic water up to its azeotrope of 98% concentration by evaporating off water from the much less volatile sulfuric acid.
The automotive store will have a very cheap pipette with floating balls to get a good idea of specific gravity for this range, you can get a higher dollar or better tools to test (concentration of acid to water) or specific gravity and in wider ranges...
edited (Change number cells, my eye sight cannot tell 6 from9 at a black wore out old keyboard)
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The concentration is measured by density. The contaminant is lead sulfate which has about 0.5% solubility in zero temperature
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It is 6 cells not 9 for 12 Volts is it not?
6x2=12 not 9x2 which will give 18V?
stella polaris
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You test with a density meter. A simple thing that is cheap (A glass pipe with a rubber balloon). That will say if they still sell it. You can evaporate the battery acid in order to get a stronger one.
My point is that he can find the concentration, but with a failed battery he will not have much control of purity, so better get new acid, if possible.
stella polaris
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A little hijacking here. Is the lead in the battery pure or is it alloyed with some other metall?
stella polaris
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If you look at youtube there is some nice videos, from the country that can do everything, India. There you can see how to renovate a car battery.
I just love these Indians and how they can restore everyting. Not always in a safe and an enviromental way so be aware. But they have made it their profession.
I just love these Indians and how they can restore everyting. Not always in a safe and an enviromental way so be aware. But they have made it their profession.
The negative electrodes are pure Pb (spongy lead), and the positive electrode is a lead PbO2 lead peroxide.
Both plates can have much of the plates converted to lead sulfate upon being discharged. more dead the more lead sulfate and less pure lead and lead peroxide the plates will contain, the more dead the cell is the more lead salts you will have.
As the cell is charged the lead sulfate which can convert back to the original lead and the acid concentration of the electrolyte also increases
Both plates can have much of the plates converted to lead sulfate upon being discharged. more dead the more lead sulfate and less pure lead and lead peroxide the plates will contain, the more dead the cell is the more lead salts you will have.
As the cell is charged the lead sulfate which can convert back to the original lead and the acid concentration of the electrolyte also increases
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stella polaris
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Thx. I will use car battery lead when i try out to cupelation
stella polaris
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I have seen that newer chargers have a function "Repair". Is this a mode that makes the lead sulfate to convert easier?
Has been my experience these repairs don’t work. If you use it on a good battery that has gone dead it will make that battery work better to some degree. It does take about 24 hours for it run the repair cycle.
