How Long Should an M240 Battery Hold a Charge When Not in Camera?

[RayD28]

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I used the camera about three weeks ago and had a full charge and took about 20 photos and then put it in the closet. The camera was turned off.  I left the battery in camera and have not touched the camera since.  Going on an outing later today and started getting equipment ready.  I checked the battery this morning and had zero charge.  How long should a battery hold a charge in camera with the camera turned off?  How long should a battery hold a full charge if stored outside the camera?

 

Thanks.  

[dpitt]

I do not know about the M240, but my M9 can hold at least half its charge after a few weeks in the closet.

[fotomas]

Never proofed it, but I would guess that my M 240 batteries hold a full load about at least 2 or 3 weeks.

[jaapv]

Outside the camera the battery will show the typical Li-Ion battery self-discharge of about 1.5% to 2% per month. In the camera it will still feed the internal battery and maybe some other circuits, leading to a slightly higher discharge rate. However, with the camera set to "off" it should hold for quite a few weeks at least. If it discharged fully overnight you probably put it in the case when it was not turned off by the switch, some pressure on the release button will keep waking it up, flattening the battery.

 

https://en.wikipedia.org/wiki/Lithium-ion_battery#Self-discharge