Macbook Air mid 2012 Battery Health

Andrei221 said:

Hello guys. I have an macbook air mid 2012, the battery has 304 cycles and the health goes from 84-85%.

I haven't tested the battery to see in real life how well it performs as i keep it plugged in most of the time.

Is there anything i can do to improve my battery health? I find 85% to be a bit low for just 300± cycles.

And another question - should i use mavericks or yosemite for a better battery life? Currently i am running yosemite.

Thank you

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Cycles isn't always the most import thing. Age, type of battery, usage pattern etc also decides. I fact, i can tell you that having it plugged in most of the time usually does more damage to it than exercising it rutinely.

DaKKs said:

Cycles isn't always the most import thing. Age, type of battery, usage pattern etc also decides. I fact, i can tell you that having it plugged in most of the time usually does more damage to it than exercising it rutinely.

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Disagree. I have always kept my MacBooks plugged in almost all the time and they have all had excellent battery health.

My previous MacBook was an 11" 2010 MBA. I sold it recently with only a couple hundred cycles on it and its battery health was still at 90%. It was plugged in the vast majority of its life.

Andrei221 said:

i now exercise it almost daily, the cycles don't worry me but the battery health. now it is up to 85,8%. i see that it increased in 2 days. how can i increase the health of it, any idea?

and again, what os is better for battery performance? mavericks or yosemite? thank you

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I think the answer to increasing your battery health lies somewhere between "nobody knows" and "there's no way to tell" and "it's complicated." Batteries are essentially random, complicated structures of chemicals and predicting their behavior is difficult, if not impossible.

There are basically two points of widely accepted conventional wisdom when dealing with Apple batteries:

1) More cycles is bad, so keep them plugged in when possible
2) High temperatures are bad (might trigger a chemical reaction that can cause the cells to swell and eventually break)

Other than that, there's no consensus on what to do, which I take to mean that it doesn't really matter.

motrek said:

Disagree. I have always kept my MacBooks plugged in almost all the time and they have all had excellent battery health.

My previous MacBook was an 11" 2010 MBA. I sold it recently with only a couple hundred cycles on it and its battery health was still at 90%. It was plugged in the vast majority of its life.

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Thats interesting. I currently have six laptops shelved due to bad batteries. Two of those are macs. They have all been solely used as desktops, only moved a few times. All had their batteries fail around or under 2 years of use.

That said, i do admit that the batteries of Macbooks can usually take more punishment than Wintel machines.

Aslo, i refurbish coporate computers for a voloneer organisation. 80% of those used office machines were docked 24/7 and in my experince those that were used properly had batteries that survied longer. Around half uad dead batteries after the three year life span. And those are all thinkpads and busness dells or hp's. So no cheap ****.

DaKKs said:

Thats interesting. I currently have six laptops shelved due to bad batteries. Two of those are macs. They have all been solely used as desktops, only moved a few times. All had their batteries fail around or under 2 years of use.

That said, i do admit that the batteries of Macbooks can usually take more punishment than Wintel machines.

Aslo, i refurbish coporate computers for a voloneer organisation. 80% of those used office machines were docked 24/7 and in my experince those that were used properly had batteries that survied longer. Around half uad dead batteries after the three year life span. And those are all thinkpads and busness dells or hp's. So no cheap ****.

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If you're refurbishing computers then it sounds like they might be a little older and might use lithium ion cells, vs. lithium polymer, so that might not be relevant.

Also, if you overcharge a lithium battery, that will quickly ruin it. Older laptops didn't have as much logic around preventing overcharging so maybe those Dells and HPs were ruining themselves when they were plugged in by trying to charge the battery all the time.

You don't give much information about the Macs.

You are not the first person to claim that leaving a MacBook plugged in will kill the battery though. Since I leave my MacBooks plugged in all the time and it's never been bad for the batteries, I have a hard time believing this.

I have put a little thought into trying to come up with alternate explanations. One is that if you leave the MacBook in the same place all the time, i.e., use it as a desktop, it might cause problems. That place might not have very good airflow/ventilation, so the laptop might run hotter than it otherwise would, and we do know that heat is bad for batteries. Or, similarly, that place might be exposed to a lot of direct sunlight (maybe at times when nobody is around to notice) and that could easily cause a heat problem.