Battery Life Charging percentage

• About Mac notebook batteries - Apple Support

https://support.apple.com/en-us/HT204054

The above is lengthy Article with additional Information links with answers.

And I recommend saving link to browser as it contains several references.

Don GG wrote:

Thank you for your attempt what I really would like is for someone to give me a percentage that is based upon experimentation

There's a ton of research that indicates that battery life (as in how much total power output before the battery reaches a certain depletion level) can be substantially increased by limiting the usable charge range. You'll hear terms including the 20-80 or 40-80 rule recommending keeping a battery within that range. The "maximum battery life" settings I've heard of keep a battery within maybe 25-75%. Tesla and other electric cars can be programmed to limit their maximum charge level to 80 or 90% of the rated maximum charge, which some believe can double the lifespan of the battery, or even longer.

However, I don't know if there's necessarily any percentage number that makes sense given than 0% and 100% are chosen for various reasons. It would be possible to select an oversized battery where the battery management system sets 0% higher and 100% lower, which would likely result in better longevity. Apple has access to the same technology for iPhone batteries as they do for iPad or notebook batteries. However, they rate the iPhone for 500 cycles while the tablets and notebooks for 1000 cycles. I suspect the battery management on the larger devices use slightly less of the available charge range to rate them for more cycles.

Apple doesn't have any way to set a higher minimum charge or lower maximum charge level. I know some here have said to never let the battery go below 40% to maximize battery life, but I've never really done it myself.

From 2005 until this year my experiences with portable Mac and various battery types

have led me to believe one could use keen insight, as one develops that; and adjust the

ability to change (your ways/means) based on conditional judgement and observation.

So far there are several user inquires here, where their issue relates to short charge interval

and/or run-flat scenarios; where the user used up battery reserves and did not choose to

seek timely recharge. ~ And continue to use their Mac as though he (little mac guy inside)

had some 'stationery pedal charger' beneath his seat.

Older macs where one had to occasionally try to revive battery storage through efforts of

Calibration, for certain models also with 'aftermarket replacement' batteries, used reason.

There are a variety of opinions on that. Apple doesn’t specifically say anything other than keep batteries from overheating and that they rate batteries for life based on the number of equivalent full charge cycles.

I personally think one should just use the battery however is convenient and replace when needed. Some notebook computer companies have a “maximum battery life” setting that can extend battery longevity, but that reduces the charge range. Apple hasn’t included such a setting.

(edited to add ending)

Depending on how far you'd have someone experiment with their hardware

may be a little extreme; one need not try very many for best results. One of

the Apple support articles suggests for storage, batteries are best left at or

near 55-65%; other numbers and circumstances are subject to vary.

Perhaps to know what to expect from the hardware and software, may be a

better field to study; and while consensus is ok for a poll, that's not a real

world happening.

(Had issues and had to Force-Quit + restart browser, and lost what I was doing

along with edits.) ~ There are times where I need a long cord & pond of water.

..And one too for the mac! I'd test the waters w/ mac first..!😳🙀🙃

K Shaffer wrote:

So far there are several user inquires here, where their issue relates to short charge interval

and/or run-flat scenarios; where the user used up battery reserves and did not choose to

seek timely recharge. ~ And continue to use their Mac as though he (little mac guy inside)

had some 'stationery pedal charger' beneath his seat.

Over the years we've learned a lot about lithium rechargeable batteries. They used to be charged like any other rechargeable battery where the charging system had to assess on the fly. Now the technology is much better where there's onboard diagnostics that store estimated capacity and other information in order to more effectively use the power and charge. I think there were some extreme lessons learned from the Sony battery factory fire of 1995 that wiped out the majority of the world's lithium-ion battery production.

Now they're all attached to battery management systems with memory. And for various reasons (safety, longevity) all batteries are set to be used with a ceiling (100%) and a floor (0%) even though there's really an attic and a crawlspace. Mac notebooks don't seem to do it, but when I've tried it on Apple's other portable devices after an auto shutdown, the display will show something indicating that it should be charged. Not sure how it does it - maybe that these graphics are programmed into the display driver and controlled by battery management.

But yeah - once it gets to 0% it's important that it be charged before self-discharge drops it to an unsafe charge level where it might be permanently damaged or might suffer a substantial loss of capacity.