Need a new battery again!

LeBlanc, DanielJ Daniel.LeBlanc at
Thu Apr 25 04:05:44 PDT 2013

Hi All.

There was mention of topping up with acid.  I have always used water.  I was not aware of the impact of topping up with acid so thanks for the explanation Bill!  There have also been mentions of overcharging being responsible for the non-sealed battery requiring fluid top-up.  In my case, the GPZ has always had a sealed battery so there has been no requirements to even check the fluid level.  However, my 1986 Kawasaki Concours has an unsealed battery and it requires topping up twice per year.  It uses an identical charging system to the GPZ - alternator as opposed to generator.  I have had the alternator apart and effected a repair and tested - the charging voltage is within factory specifications.  Is this enough to overcharge an unsealed battery?  I would not expect so.  The factory manual indicates that checking and topping up the battery is part of the maintenance requirements.

My understanding of the difference between the sealed battery and an unsealed battery is that the sealed battery has a "recovery system" in place for any vapours that try to escape during the charging process.  This "recovery system" prevents the loss of fluid and therefore the requirement to top-up the battery.  An unsealed battery does not have this feature.

Is my experience different than the experience of others running unsealed batteries?  I have run into this on both my unsealed motorcycle batteries as well as my unsealed trailer batteries (deep cycle).  Topping up every 6 months is standard practice if you do not want to be replacing these batteries every 3 years instead of 6.


Daniel J. LeBlanc, P.Eng., MBA, DTME

-----Original Message-----
From: gpzlist-bounces at [mailto:gpzlist-bounces at] On Behalf Of William K Denton
Sent: Wednesday, April 24, 2013 8:58 PM
To: LeBlanc, DanielJ
Subject: Re: Need a new battery again!

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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