Another question about the MBA, battery life and Yosemite

[OceanFrog]

I have a 2012 13' MBA with 350 battery charge cycles on the clock. I just checked my battery life on iStat pro and its showing 68% battery health.

I was a bit shocked by this as battery health under Mavericks was always in the high 80%'s / low 90%'s ... Yosemite seems to have seriously affected how my battery life shows in iStat. I upgraded to Yosemite a few days after release, and I did not do a clean install.

So I have a few questions:
1. Is 68% "normal" battery health for a 2012 MBA / 350 charge cycles?
2. Would an upgrade to Yosemite have affected battery health (or how it is showing in iStat) in any way?
3. If I did a full clean install of Mavericks would this make any difference to anything?
4. Is it worthwhile doing a full battery calibration and testing battery health again?

Thanks in advance for any answers/comments.

 

[Abbara]

What kind of battery life do you get? The health is just an indicator, it may be wrong. Battery life is generally more easy to benchmark.

Generally 68% is a lot worse than it sounds. There's some talk 1000 cycles getting you to about 80%, and if it's worse in the first year you get a replacement.

Now your battery is probably 3 years old now so that doesn't quite apply. I'd try to calibrate the battery, check the battery life itself (how many hours do you get now? vs on day 1) and consider buying a replacement battery if it's not good.

Of course Software can affect the battery but OS upgrades are always designed with the intention to minimize any negative drastic battery changes. So if your battery suddenly sucks it's a software issue (reinstalling may help, but it's unlikely to change anything if you ask me) or completely unrelated, and rather due to more likely factors like battery lifetime etc.

 

[GGJstudios]

1. Is 68% "normal" battery health for a 2012 MBA / 350 charge cycles?

It's below Apple's design of up to 80% at 1000 cycles. If you have AppleCare coverage remaining, take it to Apple for a replacement.

2. Would an upgrade to Yosemite have affected battery health (or how it is showing in iStat) in any way?

No, upgrading your OS doesn't change your battery's health or the reporting of it.

3. If I did a full clean install of Mavericks would this make any difference to anything?

It would have no effect on your battery's health.

4. Is it worthwhile doing a full battery calibration and testing battery health again?

The built-in batteries in the newer Mac unibody notebooks come pre-calibrated and do not require regular calibration like the removable batteries in older Apple notebooks. Also, calibration will not affect your battery's health.

Your battery health will fluctuate up or down over time. The gradual decline is not in a straight line downward, and it may decline more rapidly at some times and slower at others. For further details, read the CHECKING STATUS AND HEALTH section of the following link.

​

The link below should answer most, if not all, of your battery/charging questions. If you haven't already done so, I highly recommend you take the time to read it.

Apple Notebook Battery FAQ​

Generally 68% is a lot worse than it sounds. There's some talk 1000 cycles getting you to about 80%, and if it's worse in the first year you get a replacement.

It's not limited to the first year, if there's AppleCare coverage in place, which will extend battery warranty to 3 years.

I'd try to calibrate the battery

That won't restore battery health and fully draining the battery to do so isn't good for it. The OP's battery does not require calibration.

 

[quackers82]

I have the 2012 Air on 358 cycles and i have 86% battery health.