Remaining battery life accuracy

[EchoOne30]

Hey all,

I'm hoping someone can explain how the "remaining battery life" is calculated in the OS?

I find it to be inaccurate. I have a stock ATIV S on Bell in Canada. Does it calculate based on a week's worth of usage? It should be "if you keep doing what you're doing right now, it will last x long".

Don't get me wrong, I'm getting great performance out of my phone, but the remaining estimate never really syncs up with what I know it will perform like.

Many thanks.

/first post!

 

[realwarder]

I'm sure it's pretty simple and based on current discharge rate since charged. Of course if you change usage and suddenly start playing a game you're going to affect that big time.

 

[EchoOne30]

I'm sure it's pretty simple and based on current discharge rate since charged. Of course if you change usage and suddenly start playing a game you're going to affect that big time.

Right yeah I get that. But here's what I mean:

Last night I had my phone plugged in while watching a movie. I took it off charger at 12:20am, then went to bed. At the time I started this thread, I had like 79% battery left, and a 12 hr estimate.

So last night when I took it off the charger, why did I get my standard "16 hours remaining"? I broke that timeframe wide open even now, I still haven't plugged it in. I'm still above 50%.
As it was charging last night, I wasn't using it, so shouldn't it have said "at this low usage, you'll get approx. 28 hrs"?


I use the Insider app, I wonder if it pulls the usage grid from the system? If so, it seems to be taking an average based on weeks of usage. To be accurate, it should only be looking at the last... I'd say, 10-30 mins?

 

[realwarder]

Guestimating battery life remaining is always wrong however you do it when usage is not constant.

If you look at the last 30 minutes, how do you know the user won't instantly stop using it and have standby time the rest of the day(s). If you look at the rate since charged, how do you know the user won't play a game for the next 3 hours and kill the battery.

How meaningful is it when pulled off the charger as the battery has likely had no usage recently.

Only Microsoft know the exact algorithm they use but given that all algorithms are guesses, the general rule of an engineer in this instance is to keep it simple. If I were to write one, I'd do what you said - look at the last 30 minutes (or other similar period). Perhaps the default when there is no recent usage (i.e. no battery discharge for last 30 minutes) is to say 16 hours. And then over time after that it will go up or down.