[ausev] Sick Prius

[Moe Pitman]

I'm sure it applies to ANY NiMH battery pack, including the Prius.
That's why I'm counting on a fancy battery charger and up to a week of
downtime, to accommodate the re-balancing act with 38 cells.

I may contact you again for your two cents on the matter, when we
actually do it.  In light of getting the cell(s) shipped and having the
appropriate charger in place, we probably won't tackle this until Dec.
26, when transportation pressures are at their minimum.

Thanks for the input!

--Moe Pitman

On Sun, 2008-11-30 at 09:08 -0800, Gil Dawson wrote:
> I don't know whether it applies to Prii, but replacing a single  
> module in my Chevy S-10E's NiMH pack was a big magillah.  The problem  
> we had was the computer shuts the truck down if the voltages on all  
> 26 modules aren't within a tiny tolerance.
> 
> What we did was:
> 
> 1) We woke up the new module by deep cycling it several times.  We  
> rigged up a nest of light bulbs and nichrome wires that would  
> discharge the cell overnight.  A tripout relay would open when the  
> discharge was deep enough, and we could adjust the discharge current  
> by adding more light bulbs.  Then we would charge that module on a  
> commercial battery charger the next night. We went through several  
> cycles over a week.
> 
> 2) Using a 400VAC variable transformer and a diode, we charged the  
> remainder of the pack in series until all the modules -- including  
> the new one -- were within 0.2 volt of each other.
> 
> 3) Then we slipped in the new cell, closed the lid, and handed the  
> pack back over to GM's Battery Pack Control Module software.
> 
> The first trip was disappointing, because the battery voltages got  
> out of tolerance after about 25 miles, but the truck's calculated  
> range has been slowly climbing since last August.  The new module  
> still gets out of tolerance first, but it lasts nearly 35 miles now.
> 
> --Gil
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