Re: (ET) minimum charging voltage

["David Roden (Akron OH USA)" <roden ald net>]

On 12 Aug 2002 at 15:47, SteveS wrote:

> Undercharging the batteries won't shorten the life, you just
>   won't get the power out of them that you could.

Sorry, I have to disagree.  Prolonged undercharging is almost as bad as 
overcharging.  It causes sulfation, in which the lead sulfate normally 
formed on the plates during discharge forms large crystals.  These flake 
off 
and settle to the bottom of the cells.  This also causes a reduction in 
the  
electrolyte concentration (specific gravity).  

In spite of what the pulse gadget and snake oil makers claim, this form of 
sulfation is irreversible.  Sulfation results in a premature, permanent 
loss 
of capacity.

I don't know at what voltage the typical ET charger operates since I 
charge 
mine with a different system.  However, if flooded golf car batteries are 
charged with a constant voltage charger, they should be charged to about 
2.45 volts per cell.  This is 44.1 volts for a 36 volt pack.  The battery 
is 
fully charged when current falls to 2-4% of amp-hour capacity, about 5 
amps.


David Roden - Akron, Ohio, USA
1991 Solectria Force 144vac
1991 Ford Escort Green/EV 128vdc
1970 GE Elec-trak E15 36vdc
1974 Avco New Idea 36vdc
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