Re: (ET) Charging batteries

["Darryl McMahon" <darryl econogics com>]

Neil wrote:
> Interesting, Grant:  In working as applications engineer for over 30
> years on automotive charging systems, we always used a max of 14.4 volts
> (2.4 v/cell) for voltage regulator settings on a 12 volt system with
> usually 13.8 volts for "high temp" operating conditions.  I'll have to do
> some looking, must be deep cycles are different.  At that charge rate 
> they
> must use a lot of water also.  Learn something new every day.

I must have missed the original post somehow.
In deep-cycle charging applications, a finishing voltage of 2.5 volts 
per cell is typical.  This is used for a couple of hours to equalize 
the cells.  If after a long charging cycle you are not getting a 3-cell 
battery to 7.5 volts, or a 6-cell battery (marine, RV types) to 15 
volts, you are either under-charging, or your batteries are very old 
and of diminished capacity.

This does not apply to conventional automotive batteries (SLI, 
Starting, Lighting, Ignition).  Extended exposure to 15-volts on 
these batteries will cause internal heating and shorten life.


Darryl McMahon          48 Tarquin Crescent,
Econogics, Inc.         Nepean, Ontario K2H 8J8
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