optimized battery charging not working

[Doug Lassiter]

Sonoma 14.7.3 on a MBP. I want to use optimized battery charging, which will not charge the battery over 80%. I set that in System Settings/Battery/"info" on Battery Health. It doesn't work. My battery keeps charging to 100%. I actually drained the battery below 80% and plugged it back in, and it ended up 100%. What's going on?

 

[MacInWin]

The optimized battery charging resets to 100% whenever you actually use the battery and discharge it more than a couple of percent. So using it to get to 80% and then plugging it back in should result in it going to 100%, as you have indicated to the system that you do, in fact, use the battery.

Leave it plugged in and it will "learn" that you rarely use the battery and will drop the charge level to 80%. It might take a few days, but it will eventually happen. But then, when you do use the battery again for any length of time, it will return to 100% again. If you mostly leave it on mains power, it learns that is the "normal" state and gets back to the 80% level faster than if you use the battery a lot and only occasionally leave it on power.

Don't sweat this too much. The actual battery life saved by this feature is probably on the level of 1-2% max, over the life of the Mac. So, if you keep the MBP for, let's say, three years, you'll extend the battery life by maybe a week or so.

 

[Doug Lassiter]

I've left it plugged in for several weeks, and the charge never drops below 100%. I almost never use it on battery. Didn't "learn" anything. As I said, a month or two ago it was properly holding at 80%. Something changed. So, um, how do I get it to hold at 80%? But yes, I understand that the effect of 80% target charge is minimal.

 

[MacInWin]

Wait. Leave it on mains power, don't turn it off at night, just let it sleep. Eventually it will shift to 80%.

 

[RadDave]

I've left it plugged in for several weeks, and the charge never drops below 100%. I almost never use it on battery. Didn't "learn" anything. As I said, a month or two ago it was properly holding at 80%. Something changed. So, um, how do I get it to hold at 80%? But yes, I understand that the effect of 80% target charge is minimal.

Doug - I have a MBAir M2 on the latest version of Sequoia - I agree w/ Jake above that this feature can be 'squirrelly' - I go off power every other week when our cleaning service shows up - when I reattach AC my battery goes to 100%; after a day or two returns to 80% - this seemed less consistent w/ earlier versions of Sequoia - but have you considered upgrading from Sonoma? Will the macOS make a difference - don't know (of course, assume your MBP can do the upgrade?) Dave

 

[ferrarr]

Which MBP do you have? Is macOS Sonoma the highest it will go up to?

 

[Doug Lassiter]

Sorry, no. It's a MacBook Air M2. As of today, i have upgraded to Sequoia. Maybe it was just a flaky OS, and it will work now. Will see.

But as I said, it was 100% for WEEKS. Waiting didn't work. Months ago it *was* settling to 80%, but I went on travel and told it to got to 100%. When I told it to go back to 80% when I returned, it didn't do it anymore.

 

[MacInWin]

It does seem to work quicker in Sequoia than it did before. I suspect that your travel unravelled the history of usage that the system was using to predict your needs, so it need a long time to re-learn that you were not travelling any more.

I also find that it goes back to 100% for a while after any update to the system. But it learns quickly to come back to 80% if it's left powered on and on mains.

I think one "secret" is to avoid full shutdowns and just let it darken the screen to save power, but stay powered up. That seems to make the "learning" faster, at least for me.

 

[Doug Lassiter]

But why does it allow you to select "optimized battery charging', and then doesn't do it? If you're at 100%, it would be TRIVIAL to just stop charging until the charge went down to 80%. This is an "um, I'll do it when I get around it it" deal.

 

[ferrarr]

If you are inconsistent with your daily/weekly routine, it will take longer to predict your use. Also, are you using only Apple supplied MagSafe charger with the MBP?

 

[Doug Lassiter]

Actually, I am. But what does the Apple MagSafe charger have to do with anything? Also, if you choose optimized charging, why should routines have to do with anything? Apple could say, OK, we'll offer upgrades to you, um, depending on how much you use your system. Or, we'll allow you to empty your trash, um, depending on how much work you do.

 

[ferrarr]

Some people use after market chargers, and they will not work the same way Apple chargers work, like they won't charge at the same rate.

Routines differ hour to hour, day to day, or week to week, that's why the charger needs to learn your use, in order to predict when you will need the battery at full. Just like phones tablets and other smart devices.

 

[MacInWin]

Actually, I am. But what does the Apple MagSafe charger have to do with anything? Also, if you choose optimized charging, why should routines have to do with anything? Apple could say, OK, we'll offer upgrades to you, um, depending on how much you use your system. Or, we'll allow you to empty your trash, um, depending on how much work you do.

Actually, Apple does do some of that. For example, if you use TM, it takes snapshots every hour of the source drive and then copies that snapshot to the backup drive when the system is relatively idle. And then it keeps those snapshots on the source drive for 24 hours. When you drop something in the trash and then empty the trash, the system does not actually free up the space on the drive from that file as long as there is any snapshot on the source drive that has data about that deleted file. So, even though you put it in the trash and then emptied the trash, the system will NOT free up the space on the internal drive for about 24 hours or so.

As for the power setup, Apple never tells us "why" for anything, just a little bit about "how." So, the "how" is to turn it on and let it do what it does. Why it doesn't immediatly drop to 80% is not divulged by Apple, nor is the "learning" process described anywhere in detail, but from observation of those who have it turned on, it does eventually learn the individual usage pattern so that 1) the user has full power in the battery when needed and, 2) the battery life is lengthened. If it can figure out a way to accomplish both of those goals, it will drop the charge back to 80%, but if it cannot determine a pattern to the usage, the default is to meet goal number 1, full power. I can understand that rationale. If Apple were to put goal 2 first in priority, people would whine about why the battery is only at 80% when they need it all day. Reporters would be in the press claiming that the advertised battery life is wrong because it stops at 80%, lawsuits would be filed about false claims, etc, etc, etc. So, the default is to stay at 100% unless and until it can work out a pattern to use and then try to extend the battery life a bit by dropping to 80% when it thinks it can.

Oh, on the MagSafe charger? It's an intelligent device that actually communicates with the Mac about how much power the Mac wants/needs to do the charging. Third party chargers don't do that communication. It is all part of the Apple ecosystem.

And Apple offers upgrades/updates based on how busy their servers happen to be, so some folks get the offer to update the OS sooner than others.

 

[IWT]

@Doug Lassiter

Oh, I do so agree with Jake and, indeed, others. For any process that determines your battery charging, depends on your usage of your Device (Mac or iDevices). And to achieve that the Device needs to know your habits.

In particular, it requires that you follow a fairly consistent pattern - for example - you put the Device to "sleep" ie you stop using it at, say, 10pm each day and you need it at, say, 7am next day, it will follow the setup you've chosen - 80%.

But it wants to be sure that this is your normal behaviour. So it takes a few days to follow your routine, then starts the process of stopping charging at 80% (if your device allows that) or holds the 80% till an hour or two before you use it then goes on to 100%. This depends on your Device though the process is similar.

If you change your routine or if your routine is variable day to day, it struggles to find a common ground; hence the variability you are experiencing.

I'm not sure if this help, but it's the best I can offer.

Ian