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Gjwilly

macrumors 68040
Original poster
May 1, 2011
3,216
701
SF Bay Area
I repurposed my son's old 2011 Air.
He'd been using Bootcamp 100% of the time but had Yosemite installed.
When I booted back to Yosemite it had the Service Needed warning on the battery.

I then booted off a Mavericks installer to wipe the hard drive and return it to one partition.
After the Mavericks installation completed it still said Service Needed.
I then upgraded to El Capitan and after that it now says that the battery is Normal.

Does that sound normal?
 

bernuli

macrumors 6502a
Oct 10, 2011
710
403
My guess is yes, normal.

I think when in BootCamp cycles and other battery type info is not properly tracked by the OS. But just guessing here.
 

Gav2k

macrumors G3
Jul 24, 2009
9,216
1,608
I repurposed my son's old 2011 Air.
He'd been using Bootcamp 100% of the time but had Yosemite installed.
When I booted back to Yosemite it had the Service Needed warning on the battery.

I then booted off a Mavericks installer to wipe the hard drive and return it to one partition.
After the Mavericks installation completed it still said Service Needed.
I then upgraded to El Capitan and after that it now says that the battery is Normal.

Does that sound normal?
The battery is teetering on needing servicing. If you go into the system info page and click the battery you'll see its condition.
 

DeltaMac

macrumors G5
Jul 30, 2003
13,462
4,408
Delaware
Likely the battery is close to replacement time, and the system will show either normal, or Service Battery from day to day.
You can view the System Information, Power tab. That will show how many charge cycles are reported by the battery, as well as full charge capacity, and other hardware details. A 5-year-old battery may have a lot of charge cycles.
Finally, the firmware in your laptop keeps track of the battery history - not the operating system. The OS may interpret those results differently, and may use the battery differently - but the hardware doesn't change. If the battery is on the edge, you may see the message change at times, but overall, the numbers reported by the battery won't change much.
 
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Gjwilly

macrumors 68040
Original poster
May 1, 2011
3,216
701
SF Bay Area
If you go into the system info page and click the battery you'll see its condition.

Did that every time.
System info says normal.
Coconut Battery says good.

It's got over 400 cycles and it's definitely old but I don't want to replace it until I have to.
 

Gav2k

macrumors G3
Jul 24, 2009
9,216
1,608
Did that every time.
System info says normal.
Coconut Battery says good.

It's got over 400 cycles and it's definitely old but I don't want to replace it until I have to.
What is the current charge capacity?
 

DeltaMac

macrumors G5
Jul 30, 2003
13,462
4,408
Delaware
The "suggested" maximum battery cycles on your 2011 is 1,000 - so "over 400" is not so much.
The important point, I think, is to know how long you can use the battery on a single charge.
2011 11-inch Air would get 5 hours as the listed expectation. The 13-inch would expect around 7 hours.
When full charge battery life drops to an unacceptable level, then you replace. That would depend on what you (or the user) decides is unacceptable battery life. IMHO, 11-inch should be OK with more than 2 hours. The 13-inch - maybe 2.5 hours, more or less.
Anyway - you are out of warranty, so it's all up to you if that "service now" message will decide what you do with your MBAir. If it it starts coming up more often, then you get to decide if battery replacement is warranted, or even worth the cost... I know some folks that have decided to ignore the "service battery" message, and the battery continues to work acceptably.
 
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Gjwilly

macrumors 68040
Original poster
May 1, 2011
3,216
701
SF Bay Area
Thanks all.
I was just worried about it suddenly "venting with flame" as we used to say in the flashlight world.
 
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