Resetting M240 battery chip (14499 / BP-SCL2)?

[dante]

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What's the procedure for fully draining the battery, or at least getting it down to the voltage level where the % meter should be reading zero? 

- With the battery in question, there is no battery fault warning on the camera. The Nitecore ULM240 charger, likewise, reads this battery as "good."

- Battery reads fully charged on the Leica charger when it stops charging (and lights the 80% LED already when it starts)

- Battery reads 8.2 and END on a Nitecore charger when it stops charging. I did notice that it tells you how many mah it thinks the battery needs, but the sum of that plus the mah actually charged goes down very quickly (total goes from 900 to 800 to 700 to 600 within 10 minutes).

- Maximum the camera will read is 15%.

Yes, I know, "buy a new battery" - but buying a decade-old, old-stock Li-Ion battery is a dicey proposition, and not a cheap one.

Is there some way to run the camera past "0" - or slow-drain it until the battery's low-voltage cutoff kicks in? Like say using a Multifunction handgrip?

 

[fotomas]

I sometimes managed to get my batteries to zero. Easiest way is to shoot until it's empty and prevent the camera from falling asleep. Using live view also helps. With the multi-functional hand-grip you can also turn on GPS. Or taking a video is also an elegant way. Card should be formated as FatEx for this. Otherwise it will stop if 2 GB is reached.

In the manual it's said that after about 20 cycles IIRC you should empty and fully load the battery a few times to reformat it. But in general I read that it would be best form Li Ion-batteries to only go down to 20 % and only load to 80 % if you want to keep them as long as possible. Slower charging is also better then faster.

I still use the batteries that came with the camera 9 years ago, but I have the impression that they had lost capacity. That's normal over the years, even if you don't use them. So I bought some new ones. On events one battery often is not enough for one day, and for this I like to have the best possible capacity.

But the behavior of your batteries sounds a bit to me, that it might have reached the end of it's life. I have done the reformatting some times, but never got the experience that there was a major boost afterwards.

 

[laowai_]

Fully discharging a Lithium-based battery done not reset a mysterious chip that an evil manufacturer build into their batteries to induce planned obsolescence. In fact, you'll damage the battery if discharge to 0 charge. In fact you cannot discharge a lithium cell to 0 because there is a BMS (battery management system) chip in every lithium battery pack that prevents you from discharging to 0 and damaging the cells (the BMS also balances the cells, prevents overcharging and reduces the risk of battery fires).

Battery cells have a certain lifetime (a few thousand cycles, depending on the design and quality of the cell), you might have reached the end of life of your battery pack. To confirm you would have to measure the internal resistance of the cells https://www.hioki.com/global/products/resistance-meters/battery/id_6832 or better run an electro-chemical impedance analysis. https://www.hioki.com/global/products/resistance-meters/battery/id_5897 and compare the result with the manufacturer specifications.

Short of buying a new battery pack you could crack the case open, find out what battery cells are in the pack. At 7.4 V for the Leica 14499 pack this will be two Lithium cells. make sure you don't puncture the cells in the process, because this will result in a nasty battery fire.

You will most certainly find these cells on the open market on Aliexpress or similar online shipping platforms. Put the new cells into the case, seal the case and you got yourself a as good as new battery pack.  

[dante]

10 hours ago, laowai_ said:

Fully discharging a Lithium-based battery done not reset a mysterious chip that an evil manufacturer build into their batteries to induce planned obsolescence. 

I don't give Leica that much credit, though a $200 battery does make you wonder a lot more than a $50 one. The only reason I was thinking of a meter reset was that (1) the voltage and the % capacity stated seem to be way off* and (2) things like cell phones have instructions for calibrating meters. It's totally possible that Leica's meter is based on something else entirely.

*Where a battery contains cells in series at a nominal 7.4v, there seems to be no way mathematically that it can be at 0% at 7.8v. If they are in parallel (or series and parallel), maybe the controller has decided that something is finito. But if that's the case, why isn't the battery shown by the camera or charger as having a fault? 

And do these really get a few thousand cycles? Most Li-ion batteries seem to max at 500.

At some point, I may crack this open (carefully) just to see what's in it. It's probably not worth the risk to try to re-cell it. Re-celling may come if the stock of new batteries dries up or becomes unreliable. I've got a bunch of these batteries; it's just weird how this one has gone off the deep end.

Dante

[SamMen]

My Nitecore was telling me that the battery was charged and good, etc.

Popped the battery into the M240 and the camera told me different. The charger was doing this to all 3 of my batteries. I stopped trusting the Nitecore.

I went to my Leica box and pulled out the original Leica charger, popped a battery in, waited for the charge to reach”full”. Put the battery in the camera and all was good again. Did this with the other two batteries, and again, all good. They are lasting a long time,again. 
I haven’t put them back on the Nitecore, but will once the first one drains, and see what happens.