Why am I no longer getting 12 hours of battery from my 2014 Air?

[Santabean2000]

I have no idea what you're quoting and I don't know what I said that you still think is wrong.

Designing hardware/software/firmware that prevents overcharging is simply common sense. It has nothing to do with protecting irresponsible or uninformed consumers.

Will try to find the link again. In any case, the point is since the move from lithium poly to lithium ion, the basic chemistry has much remained the same. Some folks here were implying that battery tech has evolved greatly, when the truth is more complicated. Apple has made good progress at fitting batteries into custom shapes to make thinner devices, but it looks like software/firmware is significant in keeping batteries healthy (despite their owners' actions).

But the heat issue is still there.

 

[motrek]

Will try to find the link again. In any case, the point is since the move from lithium poly to lithium ion, the basic chemistry has much remained the same. Some folks here were implying that battery tech has evolved greatly, when the truth is more complicated. Apple has made good progress at fitting batteries into custom shapes to make thinner devices, but it looks like software/firmware is significant in keeping batteries healthy (despite their owners' actions).

Yes, the big wins have been to charge at different rates and not overcharge them.

Notice how your laptop/phone/etc. will get to 80% charge very quickly and then take about as long to get the last 20%. Charging slower as the battery reaches capacity improves longevity.

And monitoring the charge capacity is necessary to not overcharge them. So if your battery is at 90% design capacity and you see "100%" charge on the menu bar, then it really means the battery has "only" been charged to 90% and charging it more is probably just going to harm it.

Another thing Apple does is not attempt to maintain a 100% charge when plugged in. It will charge it to 100%, then wait until it goes down to 97% or so (which may take a few days), and only then charge it back up again.

So if you leave your laptop plugged into the wall, it will really only charge the battery very infrequently.

And again, the main source of wear for a battery is putting it through charge cycles, i.e., discharging and recharging it. If you plug in your laptop while using it, that takes the battery out of the equation and you're not putting any wear on it, so that's optimal.

Again, it has nothing to do with users being ignorant of battery technology or not being vigilant about "proper" computer use. It's just good engineering to design a thing in such a way that misuse is impossible.

----------

...
But the heat issue is still there.

There's no heat issue.

If anything, using a laptop on battery power would make any "heat issue" worse. Because batteries heat up when they discharge. So you're talking about the same amount of heat from the CPU (to do the same task) plus heat from the battery.

So if you're worried about heat (and you shouldn't be, not from any normal use of the laptop) then you should be pretty eager to plug your laptop into the wall while using it, right??

 

[Santabean2000]

Yes, the big wins have been to charge at different rates and not overcharge them.

Notice how your laptop/phone/etc. will get to 80% charge very quickly and then take about as long to get the last 20%. Charging slower as the battery reaches capacity improves longevity.

And monitoring the charge capacity is necessary to not overcharge them. So if your battery is at 90% design capacity and you see "100%" charge on the menu bar, then it really means the battery has "only" been charged to 90% and charging it more is probably just going to harm it.

Another thing Apple does is not attempt to maintain a 100% charge when plugged in. It will charge it to 100%, then wait until it goes down to 97% or so (which may take a few days), and only then charge it back up again.

So if you leave your laptop plugged into the wall, it will really only charge the battery very infrequently.

And again, the main source of wear for a battery is putting it through charge cycles, i.e., discharging and recharging it. If you plug in your laptop while using it, that takes the battery out of the equation and you're not putting any wear on it, so that's optimal.

Again, it has nothing to do with users being ignorant of battery technology or not being vigilant about "proper" computer use. It's just good engineering to design a thing in such a way that misuse is impossible.

----------



There's no heat issue.

If anything, using a laptop on battery power would make any "heat issue" worse. Because batteries heat up when they discharge. So you're talking about the same amount of heat from the CPU (to do the same task) plus heat from the battery.

So if you're worried about heat (and you shouldn't be, not from any normal use of the laptop) then you should be pretty eager to plug your laptop into the wall while using it, right??

Ha ha. Good points. I know about the 'trickle charge'.

The heat thing you can do your own tests, but any machine I have ever used is always hotter when charging and under use than on battery alone, so my experience still tells me otherwise, but then my machines and environment are different. YMMV.

 

[26139]

Okay...

Do you actually only get 7 hours or is that just what it says on the battery meter?

 

[Jacoblee23]

Do you actually only get 7 hours or is that just what it says on the battery meter?

Not quite sure yet. I haven't let it get that far since it's starting acting up. I just took it off the charger this morning and it says I have 3 hours and thirty minutes remaining. Is it normal for the time remaining bar to be off?

 

[motrek]

Not quite sure yet. I haven't let it get that far since it's starting acting up. I just took it off the charger this morning and it says I have 3 hours and thirty minutes remaining. Is it normal for the time remaining bar to be off?

Very normal. That's based on what's been going on with the computer for the last minute or so, which can vary dramatically. I've seen my battery estimate go between 3 hours and 10 hours on the same amount of charge.

The estimate is just that, an estimate. It's just to give you an idea of how much time you have left. If it's lower than you think it should be, you should investigate possible causes, e.g., an app taking up an unexpected amount of CPU power (most likely), or a battery health issue, etc.