Need a new battery again!

William K Denton wkdenton at
Wed Apr 24 16:57:39 PDT 2013

Its not so much about pH, because even a dead battery has an extremely low 
pH.  When you add sulfuric acid to a weak battery you shift the equilibrium 
of the rxn towards the product lead sulfate (PbSO4) and lock it in there. 
This disallows recharging because the sulfate ions that are trapped in the 
lead sulfate on the plates has nowhere to go because you refilled the 
"sulfate well" in the electrolyte solution with sulfate ions from the 
recently introduced acid.  You basically capped your battery's state of 
charge at the exact state it was in the moment you added the add'l acid.  It 
can never be recharged above that potential again. Science!

Bill Denton
Yardley, PA
wkdenton at
Lazarus Cycleworks, LLC
We Breathe New Life into Old Bikes

----- Original Message ----- 
From: "JOHN SOLIDAY" <johnsoliday at>

Interesting note is you really shouldn't top them off with acid as what is 
boiling off is the water vapor.  If you put distilled water in, the acid pH 
will remain constant, if you top off with acid the acid pH has to get more 
acidic so it can't be good for the cells.

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