[SailfishX]: Battery level act-dead charging 100% shows 99% when booted [closed]

[SailfishX]: Battery level act-dead charging 100% shows 99% when booted [answered]

asked 2017-11-01 11:02:54 +0200

Nekron
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I noticed mutliple times now that charging the Xperia X from act-dead mode (phone has not been turned on, but it's charging) will show a 100% charged battery level with flashing notification LED when the battery is fully charged, but once the phone has been turned on the level will show only 99%. If I put in the charger cable in again it will take approx. 10 minutes until the charging stops, the notification light flashes and the battery level shows a completely charged battery (100%).

So charging the phone in act-dead mode seems to put less juice into the battery than when the OS has booted.

The question has been closed for the following reason "the question is answered, an answer was accepted" by Nekron
close date 2017-11-08 11:57:47.530222

answered 2017-11-01 11:40:58 +0200

ghling

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The way I understand your description (fully charge the phone, unplug it, then turn it on), this is totally normal behaviour. The booting process has a rather big energy consumption since the phone has a lot of tasks to handle. Furthermore, all the energy saving options are usually applied after booting. So a drop of the battery level is totally to be expected.

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Thanks for your reply. To cross-check this behaviour I fully charged the phone (100%) while booted into SailfishOS. As the phone shows 100% I shut it down and did a reboot. Comparing to act-dead charging bootup should eat 1% of juice and I should see 99% battery level when booted.

The result was when booted again the battery level still shows 100%. So I still keep the claim that there are different charge levels between act-dead and booted mode.

Nekron ( 2017-11-01 11:51:41 +0200 )edit

Please keep in mind that the battery percentage is just a rough estimation based on the voltage of the battery. A difference by 1% is most likely within the margin of error here.

Since all the power handling is done by the hardware itself, there is no way that sailfish can temporary limit the charge of the battery. All it can do as software is querying the battery percentage from the hardware.

ghling ( 2017-11-01 13:00:55 +0200 )edit

@ghling You should convert your last comment into an answer. Battery charge level is a multi-layered pile of guesswork. The OS usually only sees three values, which are design capacity, last full capacity and actual capacity. The latter two vary to an extent which makes it neccessary to cap the calculated percentage value at 100% because it may well be above that in some circumstances. The battery IC's own usually poor arithmetics make up for most of the guesswork.

TL;DR: it's a battery level indicator only, and that's all it has ever been, on any phone with any OS.

Maus ( 2017-11-01 15:08:08 +0200 )edit

[SailfishX]: Battery level act-dead charging 100% shows 99% when booted [answered]

The question has been closed for the following reason "the question is answered, an answer was accepted" by Nekron
close date 2017-11-08 11:57:47.530222

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[SailfishX]: Battery level act-dead charging 100% shows 99% when booted [answered]

The question has been closed for the following reason "the question is answered, an answer was accepted" by Nekron close date 2017-11-08 11:57:47.530222

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The question has been closed for the following reason "the question is answered, an answer was accepted" by Nekron
close date 2017-11-08 11:57:47.530222