Re: (ET) Electric Bikes Now Legal in Ontario

["David Roden" <etpost drmm net>]

On 4 Oct 2006 at 22:30, Joel Parks wrote:

> This same scenario has been
> repeated several times since.  I wonder if the heavily-discharged battery
> tricks the charger into thinking it is full up before it really is, or 
> if the
> charger is flakey? 

My guess is that the cells in your battery are out of balance.  One or 
more 
of them is lagging behind the others.  Most NiMH chargers use delta-V 
detection, looking for a fall in on-charge voltage.  When most of the 
cells 
are charged, it sees that fall, and switches to float mode.  Restarting 
the 
charger brings up the weak cells, but overcharges the good ones.  

You may get equally good results by allowing the charger to float the 
battery for a week or two.  This isn't all that good for the battery 
either, 
but low rate overcharging is better (or less bad) than high rate 
overcharging, IMO.

I doubt that the storage had much to do with this.  It may be that some of 
them have higher self-discharge than the others, but in 16 months pretty 
much all of the charge would have vanished from all the cells anyway.

(About now David Robie will jump in here and tell you that you should 
change 
to a nicad battery.  ;-)


David Roden - Akron, Ohio, USA

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