Re: (ET) Buck/boost for E20 charger....

["Tim Humphrey" <hump evgrin com>]

Hmmm... I think it's time for a little paradigm shift...

You have individual cells!!  Get off the 6 volt, 8 volt, 12 volt thinking 
that Lead Acid has burned into your brain.

Make yourself three strings of whatever voltage you need. Add a cell, 
subtract a cell. They're 1.2 volt cells, how
much more adjustment precision do you need. Adjust your battery to the 
equipment, not your equipment to the battery.
Try a 28 cell string, don't like that, try 29 cells.



-- 
Stay Charged!
Hump
"Ignorance is treatable, with a good prognosis. However, if left 
untreated, it develops into Arrogance, which is often
fatal. :-)" -- Lee Hart

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>
>
> -----Original Message-----
> From: elec-trak-bounces cosmos phy tufts edu
> [mailto:elec-trak-bounces cosmos phy tufts edu] On Behalf Of Christopher
> Zach
> Sent: Sunday, June 12, 2005 11:07 PM
> To: Elec-trak list
> Subject: (ET) Buck/boost for E20 charger....
>
> Ok, this is going to be interesting.
>
> So I came into possession of approximately 300 SAFT NiCD cells. Each 
> cell is
> a BB600 form factor, and puts out 30-40ah at 1.2 volts. Flooded cells.
>
> That's the cool news. What I want to do is put these puppies into my E20 
> and
> get rid of the T105's. I think I can replace a T105 with 15 of these 
> cells
> (5 cells wide=6 volts, 3 ranks deep=110ah) and get a tractor that will 
> run
> full power in the summer, winter, etc for about 20 years per pack.
>
> Problem is charging them. The E20's charger ramps up to 45 volts IIRC, 
> is it
> possible to change the cap value and boost the voltage a bit higher? 
> NiCDs
> like around 1.6vpc, or 8 volts per 6 volt battery or 48 volts nominal. 
> Add 2
> volts to that for the battery control circuit I use (the TI DQ series) 
> and I
> would need the Elec-trak transformer to put out a max of 50 volts.
>
> SO any thoughts on getting that ferro-resonant transformer to have a
> slightly higher secondary without rewinding it?
>
> Chris
>
>
>
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