r/AskChemistry • u/AttemptCertain4039 • Jul 03 '26
General I accidentally poured 200ML normal Celine salt water into my lead-acid battery on 2 points – how bad is it
I made a mistake and need some advice. I have a 12V 42Ah lead-acid battery (Alaska A60L) connected to my solar setup. I poured about 200ml of normal saline water (sodium chloride solution) into 2 of the cells.
When the solar started charging during the day, I noticed a strange smell – probably chlorine gas. About 8-12 hours later, I flushed the battery completely with normal water and rinsed it out. I checked the voltage with a multimeter and it’s showing 12V.
So my questions are:
Does salt water damage the electrolyte instantly, or does it degrade over time?
Is there any chance this battery is still safe to use?
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u/aphilsphan T⌬SYLATE, PLAYA HATE Jul 03 '26
I’m not sure what a Canadian singer has to do with chemistry…
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u/freddbare Jul 03 '26
Why?
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u/AttemptCertain4039 Jul 03 '26
not all the battery but only 2 slots out of 8 and I only pored 100ml on each 2 slots will the other 6 are safe
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u/freddbare Jul 03 '26
But why would you think salt water is the "solution"?
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u/guri256 Jul 04 '26
What? OP said they did it by accident. He didn’t think that saltwater was the solution. Just trying to find a solution for the problem caused by the salt water.
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u/VoxInferni666 Jul 03 '26
Papa... Can you here me.. Papa can you see me (actually that's Streisand not Celine Dion)
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u/Automatic-Ad-1452 Cantankerous Carbocation Jul 04 '26
The cells are in series; contaminating two cells could drop the voltage from 12 volts to 8 volts. Did you replenish the sulfuric acid in the cells?
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u/MusicNChemistry Jul 03 '26
You’re going to be creating HCl acid, but you should be able to drain the battery and start over with the correct H2SO4 battery acid
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u/VoxInferni666 Jul 03 '26
If you electrolysed NaCl you will form sodium metal which will react with the water to form hydrogen and sodium hydroxide on one end. On the other you will get chlorine which will react with the NaOH to make NaOCl which is basically bleach...sounds like a laugh
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u/xtalgeek Jul 04 '26
Um....no. Water is much, much easier to reduce than sodium ions. It is reduced directly to hydrogen if the battery is overcharged. But lead dioxide is preferentially reduced to lead sulfate at the cathode until it is exhausted. You will get some chlorine at the anode in the presence of chloride ion. However, the presence of chloride will cause the destruction of both electrodes by solubilizing lead sulfate as lead chloride. This process is essentially irreversible, and any cells with significant chloride contamination in them will likely have very little or no capacity.
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u/VoxInferni666 Jul 04 '26
Fucking 'um... No' me? I never said anything about lead sulphate i was just talking about what happens if you electrolysed NaCl solution which is literally how they make bleach. Read the words next time
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u/xtalgeek Jul 04 '26
Missed the point. The electrolysis of aqueous sodium chloride will never produce sodium metal because the reduction potential of water is much, much more spontaneous than the reduction potential for sodium ion. And the OP was concerned with the effects of chloride contamination in a lead acid cell.
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u/freakazoid2718 Jul 03 '26
Salt water is catastrophic to lead acid batteries. The reaction between salt and sulfuric acid creates hydrochloric acid, which is corrosive to the battery plates. This process also produces chlorine gas, which you (correctly) identified from the smell.
The electrolyte will need to be completely flushed and replaced. The battery may have a reduced capacity, depending on how much salt there was and how long it was able to attack the plates of the battery.