Author Topic: Apple have "invented" a new way of charging LiPo batteries in phones??  (Read 2433 times)

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Offline stevelup

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How does it know at what time are you going to wake up?

It looks at your alarms / calendar etc, and failing that, statistical data. I don't have any alarms or calendar entries for the weekend, but it tells me it'll be holding off the 100% charge until just before I wake up, and the time it chose for when I was going to wake up was spot on.

I suppose if you suddenly get up hours early with no alarm, or nothing in your calendar to suggest you're going to be getting up early, then you might wake up to an 80% charged phone.

It seems pretty smart to be honest.
 

Offline ogden

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How does it know at what time are you going to wake up?
It looks at your alarms / calendar etc, and failing that, statistical data.

Right. Alarms are just "hints" for decision making. Phone analyzes it's usage patterns for, let's say, each quarter hour of the day, gather used/not statistics for recent week or two or three. In the end it can guess when you need your phone pretty well unless you suddenly break your usual daily routine. Even then you end-up with 80% charge which is not deadly at all.
 

Offline David Hess

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Rechargeable lithium cells wear out in the same way as other battery technologies.  Some reactions result in products which lock away the materials which take part of the charge and discharge process.

In the case of lithium batteries, high voltage increases the rate of these side reactions so there is some function like every 0.2 volt increase decreases operating life by half or something.  I do not remember the exact numbers.  Optimum operating life ends up being at about 2/3rd capacity depending on how the battery was rated.
 

Offline Siwastaja

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Apparently Apple have come up with "Optimised Battery Charging" as of IOS 13. From what I can gather, they are trying to suggest that charging (and keeping) a Lithium battery at 100% is bad.

"Bad", not in a sense of immediate destruction or anything like that, but yes, somewhat increased degradation rate.

This has been well known for at least two decades.

About a decade ago, everybody finally implemented this feature.

So I guess Apple is a bit late to the party.

Or maybe their marketing has just recognised that it's been long enough since this feature was sexy, so everybody's forgotten about it already and it's a fancy new feature again, like it was in 2010?
 

Offline Sal Ammoniac

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Re: Apple have "invented" a new way of charging LiPo batteries in phones??
« Reply #29 on: August 15, 2019, 07:48:41 pm »
I thought Apple had always avoided the battery spending too much time at 100% charge by running it down really fast in normal use.  :)

 ;D

As I mentioned earlier though, I am personally not convinced that this "optimization" strategy actually gets you more charge cycles (even though it is said that Tesla did something similar, that's still not a scientific study ;D ). I suspect that merely charging up to the max voltage already reduces the total number of charge cycles, however short a time it spends at this voltage (except maybe if it's VERY short ;D ). I'd be interested in seeing a proper article with actual measurements and statistics proving that this "last moment" strategy actually improves things at all.


Another reason not to charge a Tesla (or any EV, for that matter) to 100% is regenerative braking. Charge it to 100% and you loose regen braking because the current generated by the motor acting as a generator has nowhere to go. Sure, you could burn it up in a resistor bank, but there are drawbacks to that too.
Complexity is the number-one enemy of high-quality code.
 

Offline ogden

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Re: Apple have "invented" a new way of charging LiPo batteries in phones??
« Reply #30 on: August 15, 2019, 08:56:33 pm »
Another reason not to charge a Tesla (or any EV, for that matter) to 100% is regenerative braking. Charge it to 100% and you loose regen braking because the current generated by the motor acting as a generator has nowhere to go. Sure, you could burn it up in a resistor bank, but there are drawbacks to that too.

Problem you described will happen in very, very rare case when you miraculously (downhill?) accelerate without using battery charge. As long as you accelerate discharging battery, regenerative braking return less than it is spent to accelerate. It's law of conservation of energy + nothing is perfect in this world law.
 


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