M9 batteries issue and question about recalibration

[ymc226]

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I don't use my M9P or MM much anymore but I have 6 genuine Leica batteries and the 2 Leica chargers that came with the cameras which I bought new.  I'm not sure if this is the best way to preserve the batteries but I keep them out of the cameras in a dry cabinet, and charge them about every 6 months or so.  The batteries are all original from when I first got the cameras when introduced by Leica.  The last charging session (6 months ago) and today, 4 of the batteries when placed in either charger result in both orange and green LEDs blinking in a pattern inconsistent with normal charging.  The blinking frequency is either fast or or very rapid.  I assume this is an error indicator.  The 2 remaining batteries charge and indicate normally.  

I do have a Delkin universal dual charger with the Leica M8/M9 plates that does successfully charge these "non-responders" successfully and once charged, each of these non-responders for 400+ shots.  I also do not get any error messages in the cameras when using these affected batteries.  I was thinking of running down the batteries to recalibrate them to see if they will then charge with the Leica chargers.  Not wanting on relying on the Delkin chargers just in case I want to travel with them in the future.  Can I just turn off the Shut Off function and keep the LED screen on to run down the batteries?

[dpitt]

I think most new batteries are charged to 50% for storage. Storing empty batteries will shorten their life. Using them regularly seems to extend life. I think that there is a lot of variance in the lifespan of any given type of battery, so it is hard to judge by individual experience what works best.