RE: (ET) time for a new pack...

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

On 9 Aug 2001, at 13:57, Elie, Larry (L.D.) wrote:

> "The recommended best
> charging method  for industrial use is constant current until about 90%
> of full charge, than constant voltage to complete as this is
> automatically self limiting.  Use about 2.35 volts max per cell. 

This is a good value for VRR (sealed) batteries, particularly gel 
batteries, but I think a little too low for flooded batteries.  You 
should aim for 2.4 to 2.5 volts per cell (use the lower value for older 
batteries).

Here is a good basic flooded-battery charge algorithm that requires very
little babysitting:

Constant current to 2.45 volts per cell (measured while on charge), 

Constant voltage at 2.45 vpc until current falls below 2-4% of the 
battery's amp-hour capacity,

Followed by shutoff most times, but periodically followed by an 
equalizing charge at that same current until one of the following 
happens:  

 - 1-2 hours elapses; 
 - voltage stops rising; 
 - voltage exceeds 2.5 volts per cell. 

The above requires either very close watching of the battery or a "smart"
charger with a well-designed charge controller.  The GE charger definitly
doesn't qualify as "smart."


David Roden - Akron, Ohio, USA
1991 Solectria Force 144vac
1991 Ford Escort Green/EV 128vdc
1979 General Engines ElectroPed 24vdc
1970 GE Elec-trak E15 36vdc
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