Does constant charging extend the battery life span of my MacBook Pro M3?

There is no need to change your behavior and when you are next to power, plug it in. All you need to do is use the Optimized Charging setting and let it do its thing. The Power Management on your MacBook Pro is very good and you do not need to worry about your Battery Health. There is no need to use any third party battery management, such as Al Dente. That particular question has been asked and dismissed.

Al Dente vs MBP Optimized battery charging - Apple Community

Just follow these 3 simple rules:

• Turn on Optimized Charging
• Plug your Mac in whenever next to power and leave it plugged in.
• Enjoy your Mac.

Optimized battery charging attempts to BALANCE 'battery long life' against 'having enough Charge for the things you do off power' with your Mac.

if you have recently have been using your Mac off-power frequently, or more than a trivial amount, the algorithm will be optimized toward 'having enough battery charge for your off-power use'.

if you leave it plugged in (I think about a week will do) it will allow the charge to decline toward the 'long life' side of the balance.

THE BIG take-away: do not anguish over battery long life. Enable battery health management and forget about micro-managing -- let the computer take care of it.

If you're going to leave it plugged in all/most of the time (which is fine), make sure you have the option to optimize charging on (System Settings > Battery, click the (i) button to the right of Battery Health). That will result in your battery being held at ~80% charged when connected to power, which is much better for the battery.

No, unfortunately, batteries have greater lifespan when not left fully charged. I use the application AlDente to set a charge limit while plugged in to extend the batteries lifespan.

Apple have a help page on taking care of batteries too, linked below:

Batteries - Maximising Performance - Apple (UK)

[Edited by Moderator]

bailtree wrote:

Except that I've never seen the optimised battery charging fuction actually limit the charge

Probably because it's usage dependent. If you frequently run on battery, your Mac will routinely charge to full. If you usually run plugged in, it will hold at 80%. It adjusts the charging as needed if your usage pattern changes.

This is what the battery icon shows on my Mac that I usually use connected to a dock:

But if I run on battery a for a couple of days, it will charge to full instead of pausing at 80%.

In other words, macOS manages it dynamically instead of simply setting a hard limit.

Leaving your MacBook plugged in all the time is generally safe for your Battery Health. However, you should never your MacBook drop below 20% or completely run out of battery. This rule applies to all rechargeable lithium batteries and is the worst thing you can do to them—letting them get low or die.

Also, when your MacBook reaches below 80% battery Health or below, you should have the battery replaced.

Learn more ⇢ Batteries - Maximizing Performance - Apple

Before the support articles here were "streamlined" at the Altar of Minimalist Design, there was a very good, in-depth Apple battery care article that recommended using the computer on battery once a week or so. It basically stated that a lithium battery, like a muscle, benefits from a bit of exercise. Although Apple power management system are better today, the underlying battery technology is much the same.

My Macbook Pro runs on battery once a week when I work a volunteer job with limited access to wall outlets. Its original battery cannot run as long as when it was new, but still delivers acceptable runtime for my needs. The battery turns 11 years old last June.

One caution: "generic" battery maintenance site recommend "calibration." Apple stopped the recommendation to "calibrate" about 2009. Calibration involves running the battery to zero, not a good thing if done repeatedly.

bailtree wrote:

Except that I've never seen the optimised battery charging fuction actually limit the charge

It does on my MBP and did on the MBA I traded in last month. I see exactly what neuroanatomist shows.

Except that I've never seen the optimised battery charging fuction actually limit the charge

bailtree wrote:

Except that I've never seen the optimised battery charging fuction actually limit the charge

I see it constantly, My MBP M1 hovers around 80% most of the time.

Petite Sirah wrote:

Thank you for giving me peace of mind!

Have a great day.