Re: (ET) Fully charged pack voltage

["David Roden" <etpost drmm net>]

On 24 Apr 2009 at 20:56, Jim Coate wrote:

> I seem to have missed the beginning of this... what does the electronic 
> timer do that the mechanical one doesn't do?

If you're talking about the Lester "timer," they only call it that because 
it replaces (replaced?) the mechanical timer on their simpler chargers.  
It's a true charge controller, a logic circuit which carries out a dv/dt 
charge algorithm.  

Once the battery reaches a threshold voltage, it monitors charge current.  
When the current stops rising (or shows no increase over a period which I 
don't remember any more), it shuts off the charger.

Dv/dt is one of the most elegant and effective charging algorithms 
available 
for lead batteries, because it automatically accounts for the age and 
temperature of the battery.  At one time Lester had a patent on it, but I 
don't know whether that's still in force.

As for whether it can be fitted to the GE charger, as I said, the Lester 
circuit I have suggests that it may not be trivial.  I haven't studied it 
closely yet.  I'll be interested to hear the results if someone tries it, 
so 
please post.


David Roden - Akron, Ohio, USA

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