M10 battery - hold charge when stored

[TomB_tx]

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Has anyone else noticed that the M10 batteries lose charge faster than M9 batteries while unused, either in camera or out? Since I shoot mainly film I’ll keep a charged battery in my kit for a month or more before swapping, and an M10 battery is normally down to 80% in that time. But an M9 battery hardly drops at all in that time. The batteries have gone through many charge cycles without a change in this behavior.

[Robert Blanko]

By coincidence, after about 6 weeks of Covid caused separation from my M10, I found a replacement battery in my backpack today. I didn’t remember that I had one, so I was very happy in the first second. But when put the battery into the camera, it turned out to be empty. Camera remained dead.

While there is of course some uncertainty in this case 😉 , this surprised me and this would match your observations.

[SmokeSolid]

Nothing like the M240 Baterry  

i really miss the capacity for long trips. I bought two and i never used the second in a complete day of shooting (or maybe twice I have used more but it gave me atleast 700 shots per charge. ) 

[Hannes Lummes]

I noticed a bit different and very annoying issue: Batteries seem to drain when camera is not used, *but* the remaining charge metering does not fully take it into account somehow. When I shoot with the camera after a couple of weeks it notifies me of the low remaining charge already at 40%. If battery is freshly charged the same happens at 10%. This has caused me to miss a lot of photos, since I was not able to foresee the batter running out.

[W124]

I forgot to switch off the camera and stored it in standby for over two weeks. Battery was at 94% when I recognized my mistake.

I was very positiv surprised!

[jonco]

I rotate my batteries monthly.  After sitting dormant my M9 batteries will be at 95-100%, the M10 batteries will be at 80%. I have 4 batteries for each camera. M9 batteries are about 5-8 years old, the M10 batteries 2-3 years old. And they are awfully expensive for such weak performance.

Edited June 29, 2020 by jonco

[farnz]

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On 6/23/2020 at 5:53 PM, Hannes Lummes said:

I noticed a bit different and very annoying issue: Batteries seem to drain when camera is not used, *but* the remaining charge metering does not fully take it into account somehow. When I shoot with the camera after a couple of weeks it notifies me of the low remaining charge already at 40%. If battery is freshly charged the same happens at 10%. This has caused me to miss a lot of photos, since I was not able to foresee the batter running out.

This is a behaviour of all batteries and all battery meters the world over, not just Leica and not just the M10.  

A battery meter tries to estimate the electrical capacity left in the battery but a battery simply changes chemical energy into electrical energy, so any estimate of the electrical capacity is an indication of the chemical capacity left in the battery.  To estimate the remaining chemical capacity requires the meter to cause the chemicals to produce a small current, from which it can then estimate the remaining chemical capacity and turn that into an estimate of the remaining electrical capacity.

Battery meters are designed to take the tiniest current so that the battery's capacity is not used up in metering the battery but the downside is that the tiny current produces a naturally high potential error in the battery meter because the current is so small.  This makes real-time battery meters fairly inaccurate much of the time.  I could mention the 'knee of the curve' of battery capacity but that might put the few of you who have got this far to sleep.😄

Accurate battery capacity measurements can only be done through discharging the battery to a set point through a known resistance.  Unfortunately that's not appropriate for cameras because you'd lose most of your battery capacity through metering so we're stuck with what we have and it's wise to distrust the battery meter and err on the conservative side, especially when the battery hasn't been used for a while.

Pete.

[Jeff S]

Similar disparity between my M10 and M9 Monochrom batteries.  The M240 battery was the best.  But no big deal, once one learns behaviors and is prepared.  

Jeff