Is it possible to calibrate the battery voltage measurement?

just so you know, the % (capacity left) indicator is not a voltage measurement.

Well, even if the percentage does not tell the voltage as such, I suspect the indicator is calculated from a voltage (and potentially current) measurement. Please let us know if you have information that this is done in a different way.

Update: I've not seen the battery display go up just like that in a very long time. Sometimes the value jumps after a reboot, a few times even by more than 5 % (both up and down).

But another peculiar part is that the percentage points charged from a PC's usb don't seem to last as long as the percentage points from the wall plug. I.e. the battery percentage seems to go down a lot faster after charging from a PC compared to charging with the plug charger. This cannot be seen always, but quite often, e.g. after I have used the debug network interface via usb. I have performed the discharge-completely-then-charge-while-switched-off-trick in the mean time, but still see this issue.

So while my observations are a bit different nowadays, it'd still be nice to get some light into this matter.

Update2: I noticed that the percentage gets mixed up basically always after rebooting using SailfishReboot. It usually shows something close to 100% after a reboot, no matter what the real situation is. When switching the phone off and on again, the 'real' percentage returns.

Same question for me. Battery level display is totally weird after replacing the original (dead) one. Connected to the wall plug it rarely reaches 100%, instead goes to some value (e.g. 76%) and than decreases while plugged in. Sometimes it does not go beyond 40%, but sometimes 100%. Loading time does not mater. Wall plug or PC cable is just the same. I see spontaneous reboots at various battery levels, sometimes multiple cycles. To stop that, I take out the bat, wait a while and start up, facing a percentage that has nothing to do with the pre-shutdown value. Clarification of any kind would be great. (Well, if there would be a suitable replacement phone available I'd drop the J1 immediately (since there is no original replacement akku avail, presumably). This battery thing is driving me nuts. But no chance to find a non-Android/iOS phone that's not too large...)