I've a fairly new acid battery but its gone flat through non use over a couple months (not through a quick discharge).
It now seems to have a dead (or at least bloody lazy) cell and though it will charge to 12 volts, quickly drops back to 10V, and does not have the guts to realy tutn the engine over quickly.
I seem to remember various addative mythical methods of unclogging a battery cell quite successfully - Does anyone have a good remedy / product that has worked for them?
Apparently you flatten the battery completely and then reverse charge it briefly. However my memory is hazy on this subject and as it can be dangerous if done wrong I'd advise against it. Take it back under warranty (they're usually 2yr nowadays) or buy another if out.
(Quote from the above link) "Replace the old electrolyte with distilled, deionized or demineralized water, let stand for one hour, apply a constant current at four amps at 13.8 VDC until there is no additional rise in specific gravity, remove the electrolyte, wash the sediment out, replace with fresh electrolyte (battery acid), and recharge. If the specific gravity exceeds 1.300, then remove the new electrolyte, wash the sediment out, and start over from the beginning with distilled water. You might have to increase the voltage in order to break down the hard lead sulfate crystals. If the battery gets above 125° F (51.7° C) then stop charging and allow the battery to cool down before continuing. Cycle (discharge to 50% and recharge) the battery a couple of times and test capacity. The sulfate crystals are more soluble in water than in electrolyte. As these crystals are dissolved, the sulfate is converted back into sulfuric acid and the specific gravity rises. This procedure will only work with some batteries."
I think I'd rather just replace the battery, than go through that bloody lot! Probably wouldn't cost much more than buying the acid anyway.
And with many/most modern batteries you can't access the cells to do it anyway. The days of unscrewing the tops and checking the level are but a memory now.....
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