Do I need to calibrate the battery of my Macbook Pro?

If it's an Apple original battery, there's no need to calibrate it. It already comes ready to work with your computer, so you do not need to perform any additional task

Your model Macbook Pro needs calibration. Read the manual that came with your Macbook Pro for calibration instructions. Or you can download the manual for your model Macbook Pro from Apple's download manual site - https://support.apple.com/manuals/macbookpro

Since your MBP has a 'non user replaceable' battery, you need NOT calibrate it. Please read this Apple support article.

https://support.apple.com/kb/PH14087?locale=en_US

Ciao.

Please disregard my previous response. My first 2 sentences are incorrect. Sorry. Everyone else responses are spot on.

You also should NOT run your battery down really low to eliminate the "memory effect".

The Lithium batteries used in Macs do not suffer from the "memory effect" (a problem only with Nickel-Cadmium batteries), and running Lithium batteries down low shortens their lifespan.

Question 1:

What is the reason the non-removable battery laptops don't need calibrating? People say that it is "pre-calibrated" when new. Well that's fine when it's new. But the battery loses capacity over time through discharging, heat, and even sitting idle. These variables mean that everybody's battery will be different. How can the computer know your battery's current capacity, if you never run it down, without a calibration?

Question 2:

If it's the case that calibration is no longer required, does that mean that the newer Macbooks with built-in batteries can be used on wall power ALL the time? Can it negatively affect the battery lifetime versus running from battery? Hypothetically, what would be the ideal use pattern that would offer the longest battery life time. (Percentage of time on battery and on A/C, depth of discharge, frequency of charge etc.) Would good charging habits SIGNIFICANTLY improve battery life? If so, how much would one expect to gain?

I'm sure somebody in a lab somewhere has done such experiments.

1. How can the computer know your battery's current capacity, if you never run it down, without a calibration?

Because guys at Apple already did these tests on typical batteries of every type currently shipped, and developed a battery-type profile for each battery. That is now used instead of having to calibrate each and every battery in the field. They also claim non-removable Apple batteries are "factory calibrated" so you don't have to calibrate.

2. does that mean that the newer Macbooks with built-in batteries can be used on wall power ALL the time?

Yes.

They used to advise that a Mac Used on power at all times should be "exercised" by using it on battery once a month. That advice has been removed from the article on notebook batteries cited above. So it appears once they did their lab testing, they found it did not make an appreciable difference.

So use it the way you like, and don't worry about battery issues. The computer is taking care of it so you don't need to worry about it. Deep discharge does tend to shorten battery life, so try to avoid that when possible.

That's nice to hear that we don't have to babysit batteries any more.

But as I said, how can they predict the usage of every battery? Person A is going to be using it in a hot Arizona desert. Person B is going to be using it in Alaska, but runs it down to 0% each time, etc. Each of their batteries will have a noticeably different lifespan. The only way I can see that Apple could account for that is by careful onboard monitoring and logging of battery temperature, charge/discharge details and having a sophisticated algorithm calculate a live capacity figure. This seems implausible, and even then, then it will be inaccurate since every battery will inevitably age differently. If there's anything I've learned from all the lithium battery scandals (Samsung, Boeing, iPods, pretty much all laptop manufacturers including Apple ...) it's that our understanding of them is inadequate.

They do have contemporaneous measurements of capacity (in milliamp-hours) at full charge, and can use that as one indication of battery "age". You can see these measurements in:

about this Mac > System Report > Power

The Mac does not let you run that battery down to real zero. I am not sure exactly what the number is, something like 20 percent, then your Mac goes to sleep, then hibernates (writes memory image to disk and shuts almost completely off),