Hi everybody,
As I can see from this forum many of the problem in the Vectrix Battery pack are due one or two weaker cell that go in "cell reversal" and cut a lot of range.
Personally I own an E-max Scooter ( soon to be converted to Lithium by me) but I have some experience on battery.
So I was thinking about doing this procedure to trying to get the max out of a damaged battery pack.
Full Charge with equalization
Full discharge
Opening the Bike , testing each cell to find witch are in "cell reversal" condition,
wired this cell to a companion "Buddy cell" like this one
http://www.all-battery.com/nimhdsize10000mahhighcapacityhighratenimhrechargeablebattery-1.aspx
( a normal D size cell with a capacity of about 10Ah )
Paralleling the weak cell and the buddy cell create a cell with a grater capacity were the high current load still be carried by the Original Vectrix cell , the buddy just provide an extra beef to keep the weak cell alive and avoid cell reversal
Anybody of you tried this solution to save a still good pack with a few weak cell?
I know is a huge work to dismount the battery pack but the buddy cell cost a few dollars and you just need to buy cell just for the weakest in your pack so is a less than $50 fix to have a pack back in a good shape
be aware of the voltage drop as a nimh cell appraoches full.
basically it precludes you from parralleling two nimh cells while recharging.
Newer imh cell designs don't have this problem, but the nimh cells used in the Vectrix are of the old design.
IMO, when you only have 2-3 cell failures, it is best to just short them out of the circuit with a copper bussbar.
Matt
Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah in July 2010. Done 194'000km
Yes , but pairing an additional 10Ah cell will keep the pair away from the full charge because the other cell will full up first keep the pair under the "hump"