RE: Sparrow II-regulators

["BillDube@killacycle.com" <BillDube@killacycle.com>]

>
>Now I hear that Corbin is selling the cars without regulators.


         I think this might be at the advice of Optima, believe it or not. 
Optima was recently taken over by Johnson Controls Inc (JCI). Not long 
after the take-over, they  laid off the entire Optima R&D staff. JCI 
doesn't really fully understand Optima batteries, and likely does not have 
a lot of hand-on experience with long strings of AGM batteries.

         Until you actually try the experiment, it isn't obvious that 
regulation is required on long strings of Optimas. Then it becomes 
painfully obvious.



>I'm of the opinion (which may be a minority one on this list) that
>battery-level regulators aren't really the right answer.  What is really
>needed is charge control for each individual ~cell~. Because each cell
>has slightly different manufacturing tolerances, they will inevitably get
>out of balance, even with battery-level regulators applied.  There's
>still no substitute for periodic equalization.


         I've played with different levels of equalization. It comes down 
to cost-benefit. Yes, ideally, one should regulate at a cell level. In 
reality, the most optimal level (for AGM lead-acid) is about 6 cells. The 
more expensive the cell, the fewer should be grouped together.

>But when the modules are stuffed into whatever cavities are available in
>the vehicle (as they are in most conversions, and in the Sparrow), there
>is bound to be a lot of temperature variation.  This is where I think
>regulators are probably necessary.



>In the case of the Sparrow, though, some compromises seem to have been
>engendered by major component choices.  For example, my impression is
>that motor choice (and brush timing) created certain controller concerns.
>
>Similarly, the charger they chose may have interacted in unpredictable
>ways with battery regulators.  Those familiar with this charger may have
>a better handle on that than I do.
>
>In any case, it's pretty clear that Corbin knew about battery regulators,
>and decided to not use them.
>
>If they didn't decide for technical reasons, then it was for financial
>ones.  I hope it's the former, because if it's the latter, I believe that
>they are hurting their long-term vehicle sales for the sake of a lower
>price today.


         The Sparrow folks really don't seem to have a good handle on the 
electric drive train. They are having problems because they are not 
experienced in these areas and are perhaps listening to bad advice (or not 
listening to good advice.)

    _ /|        Bill "Wisenheimer" Dube'
   \'o.O'     <billdube@Mega-Cycle.com>
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