High battery drainage Xperia 10 III

My last flash was in August 22 and my cycle count is 37. I am also using battery budy and charge only to 85%.

Then something else must have reset the counter at some point (or it stopped working altogether) in both of your cases, as its value is technically impossible for such long periods of time…

Can you please:

  • check what’s the date of last update of that cycle_count file
  • check in a few days (a few chargings) if it has increased?

Thank you.

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I flashed my phone only once in May '22, but updated it regulary:
/sys/class/power_supply/battery/cycle_count → “1”

I re-flashed my phone September 29 (that’s the earliest date I can find in file browser, and it matches my memory of having flashed early this autumn) and my count is 32 (was 31 two days ago).

What makes you think something must have reset the counter?

As i earlier stated:

check what’s the date of last update of that cycle_count file


check in a few days (a few chargings) if it has increased?

I don’t think it will unless a full recharge cycle is made.

No, this is a wrong assumption. This counter (which is also present on Android) works the following way: the process controlling it silently adds up every mAh that you feed into your battery, and when the number of mAh fed into the battery reaches its capacity (which is 4500 mAh in case of the 10 III), the counter increases by 1. In other words, if you do a full charge from 0 to 100% at once, this counter will increase by 1 right away. But if you do partial rechargings, it will wait until those rechargings SUM UP to the battery capacity, and then it will increase by 1, too. For example: a 40% recharge (1800 mAh) + 20% recharge (900 mAh) + 20% recharge (900 mAh) + 13% recharge (585 mAh) + 7% recharge (315 mAh) = 4500 mAh in total and will make this counter increase by 1. Fully confirmed by my own observations on my device (and formerly on my BlackBerry Passport, too).

But that’s only if the process/service/whatever that controls this counter works correctly, which is clearly NOT the case with your phone, or - even more clearly - with @Speedy-10’s phone, whose counter is 1, i.e. doesn’t work at all.

Mine is now at 108, despite NEVER having fully recharged my phone, as I never discharged it below some 20-25%, not to even mention to 0%. I always recharge it daily, usually with 30%-50% still remaining.

I don’t know what causes it not to work on some phones. Maybe it doesn’t react to some types of chargers, or God knows what else.


I agree, it makes sense. May i ask, is this based on actual information on cycle_count behaviour or just observation? I would just like to confirm.


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Oh please, elaborate.

But what?
I already described how it works and that my long time observations on two different phones confirm it. Where I read its documentation, I don’t remember, I guess you can try to google it yourself…

So i guess your assumption is as good as mine. Which is just fine. I just wanted to check.

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Can you call Jolla for an update? :>

First of all, i said mine was a guess, and commented your explanation “i agree, it makes sense”, but when i asked for something to back that explanation, it felt like yours is just another guess (like mine). You have to understand that in this kind of situation the burden of proof is undeniably yours.

And second of all, there is no need to be rude. And there is no need for an argument. If you feel like arguing with someone, please keep away from this forum.

I would also like to hear the facts from Jolla devs, since my guess is worth nothing, and @wetab73 is just quoting random stuff about laptop batteries and from Apple support (?) and showing that there are apps.

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Do you really talk to people like that face to face?

Do you think that is acceptable behaviour on this forum?

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It’s amazing but yesterday I did the very same thing (stopped the Battery Buddy service and allowed the phone to recharge to 100%) and guess what… After I went to bed and set the phone as usual (only mobile network for voice calls enabled, mobile data off, wifi off, bluetooth off, gps off, Android support off), when I woke up only 4% were consumed (compared to the usual 8%-9%) and each 1% lasted 1 hour 50 minutes rather than the usual ~ 1h:00m - 1h:15m. Now at 23:00 in the evening I still have 82% battery left, whereas normally at that time of day I only had 55-60%. Of course, I charged it 10% more than the usual 90%, but the difference is much more than that.

I guess that the battery must have re-calibrated itself when it was allowed to fully recharge, and the indicator now uses correct units (1% is now really 1%, i.e. 45 mA) whereas previously the % indicator must have been kind of de-calibrated, and the % units were smaller than in reality so they were decreasing too fast.

Let’s see how long it is going to last so, and what enabling Battery Buddy limits will cause…


Flightmode standby drain with remains the same at 0.7%/hr (not that any difference was expected)

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… and after 25 hours of normal use I still have 70% left. Power consumption seems to be actually the same, so - as I wrote - the battery level control must have undergone some kind of recalibration. I don’t remember it lasting that long ever. Now even with WiFi and mobile data on, 1% lasts 1h:00 - 1h:05… Magic…

It looks that it is very useful to recharge the battery to 100% once in a while to calibrate it.

I had the following out of sync (much lower than actual power level):


and recharging to 100% fixed it.

This counter should reflect the level of charge (in mAh) left in the battery (in case of 10 III it should be eg. ~4500000 for full, ~2250000 for 50%, etc.). If it gets out of sync, I guess that the % indicator gets incorrect, too (decreases faster than the actual power draining).