[Leica] more info on the M9 3rd party battery mystery

[Richard Taylor]

Kyle - Since they behaved this way that are probably NiCd batteries though some other varieties behave this way, too, I believe.  This is normal behavior for batteries of this type when left on charge for a long time and only lightly discharged.  NiCd batteries are at their best when they are deep discharged regularly.  I’m not strong on the chemistry involved but you can find a more detailed explanation here: 

http://batteryuniversity.com/learn/article/how_to_restore_nickel_based_batteries 

One space mission I worked on deep discharged the spacecraft batteries routinely as part of a battery conditioning program to keep them fully functional over the lifetime of the mission.  I have a GPS that requires I periodically fully discharge the battery (sometimes twice) before it will hold a charge again.  (It is almost alway run plugged into the cigarette lighter of my car when in use.)  

My memory is more vague on this, but i believe some NiMH batteries behave this way, too. 

Sounds like entirely normal behavior to me.  

Best, 

Dick
BSEE
City College of NY 1962

On Feb 27, 2015, at 11:58 AM, kyle cassidy on the LUG <leicaslacker at gmail.com> wrote:

> Based on input from a lugger, I tried draining the batteries completely, then recharging them to 100% and putting them in the the camera — where they worked perfectly and lasted longer than the OEM battery. 
> 
> No idea why this happens, well, I have some idea, but it’s all vague. Thoughts from electrical engineers?