Battery

The "3 tools” program (I assume you mean 3utools) is not an app with any validity; the actual battery condition is saved in the battery itself, and the phone’s display of its condition is the only valid one. 3utools is a hacking program; if you have actually jailbroken your phone then no further discussion is meaningful or even permissible in an Apple forum.

Your battery is expected to remain above 80% for 500 full charge cycles, as described in my link in a previous post. That means it is expected to drop roughly 1% for every 25 charge cycles. If you do things that might shorten its life, such as letting the charge go to zero regularly, then it may not last as long. However, it isn’t always linear; mine remained at 100% for over a year, then dropped to 95% over a short couple of months. And it has been at 95% now for about 6 months. You also need to record the battery capacity at the same state of charge each time for it to be most meaningful; ideally when the charge is 100%.

The message under Peak Performance means that the battery is failing. Batteries have several different failure modes, not just loss of capacity over time. Your phone needs a new battery.

There’s a apparently nothing wrong with the battery. Apple changed that message on the iPhone 11 and later.

The only thing you should do that you may not be doing now is to charge the battery overnight, every night, with Optimized Charging on. This is the best way to extend the useful life of the battery, because when it is plugged in and charged to 80% or higher the power to run the phone comes from the power lines rather than the battery, allowing the battery to “rest”.

There is no reason to wait for it to go below 20%; its not even a good idea to do that. Charge it when you are finished with if for the night, regardless of what the charge level is. If it goes below 20% with normal use during the day you should charge it, mainly so the battery won’t run down and shut off while you are using it.

Since you seem to be curious about the battery here is the long answer→When to charge your iPhone or iPad - Apple Community

This note:

means that the battery is failing. It’s a subtle message, but if the battery was in perfect condition Under Peak Performance Capability it would say:

Your battery is supporting normal peak performance.

No, it won’t be a problem. The phone’s charger is in the phone, and it will stop charging when the phone reaches 100%. You can leave it plugged in after it reaches 100% without hurting it. You could even leave it plugged in all the time, if you wanted to. It’s actually good for the battery for the phone to be plugged in after it reaches 100%, because any power the phone needs will come from the external power source rather than the battery, thus reducing the need to discharge and recharge the battery. That (and other facts) are discussed in the link I posted.

Your battery is OK, and will be OK as long as the maximum capacity stays above 80%. However, you should follow charging best practices to get the most life out of your battery.

That's funny you should say that Lawrence. My iPhone 12 Pro is displaying the same message and my battery health is at 100%. I'm not experiencing any issues, but when reading your message I decided to look at mine. I remember the peak performance message, and looking at my wife's iPhone 12, which was new on December 15, 2020 is showing the same message and 100% battery health. I wonder if the standard message has been changed.

deggie wrote:

Lawrence, that message is on all phones, it changes if the battery is failing and it throttles it. Check yours.

It is not on my phone. Mine says

Your battery is supporting normal peak performance.

mhamed16 wrote:

You mean to put the phone on the charger and then sleep it up to 100% every night?

Yes. It will charge to 80%, then stop charging. It will resume charging to reach 100% around the time you usually get up and take it off the charger.

If you turn on Automatic Backups it will also back up the phone each night as its charging, so you will have a fresh backup at the start of the day.

Because you are not charging it enough.

When not in use. Day and night. You can not overcharge it.