Battery issue I think?

iburt

macrumors newbie
Original poster
Aug 17, 2012
3
0
I just bought a used MacBook. It's 40 months old. The battery has 36cycles. Max capacity was 4600 and it's down to around 3700.

Now here's the issue when I unplug it as soon as the charge gets below 90% my capacity drops to only 1260 and I discharge quite fast? But as soon as I plug it back in and it gets above 90% my capacity goes back to normal?

Thanks for any help.
 

GGJstudios

macrumors Westmere
May 16, 2008
44,419
756
I just bought a used MacBook. It's 40 months old. The battery has 36cycles. Max capacity was 4600 and it's down to around 3700.

Now here's the issue when I unplug it as soon as the charge gets below 90% my capacity drops to only 1260 and I discharge quite fast? But as soon as I plug it back in and it gets above 90% my capacity goes back to normal?

Thanks for any help.
You can try resetting the SMC, but you likely need a new battery.
With only 36cycles??
You should really have more cycles than that, if you want to keep the battery healthy. It's not good to leave it on AC power all the time.

This should answer most, if not all, of your battery/charging questions:
 

miles01110

macrumors Core
Jul 24, 2006
19,269
30
The Ivory Tower (I'm not coming down)
You should really have more cycles than that,
Actually 36 charges on a 40-month-old Macbook fits in pretty nicely with Apple's guidance.

Apple recommends charging and discharging its battery at least once per month.
Your battery guide should be updated to reflect this instead of the "discharge every 2-3 days" statement you have in there now.
 

jav6454

macrumors P6
Nov 14, 2007
16,871
1,492
1 Geostationary Tower Plaza
If it's over 3 years old regardless of the number of cycles the battery has passed its lifetime. Plus the evidence you've provided suggests a fault. Buy a new battery and be done with it.
True. A battery that hasn't been put to use will go bust even faster.

Actually 36 charges on a 40-month-old Macbook fits in pretty nicely with Apple's guidance.

Your battery guide should be updated to reflect this instead of the "discharge every 2-3 days" statement you have in there now.

miles01110 nailed it pretty well. I bet you didn't even read what you post.
 
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GGJstudios

macrumors Westmere
May 16, 2008
44,419
756
Your battery guide should be updated to reflect this instead of the "discharge every 2-3 days" statement you have in there now.
Actually, it shouldn't. Apple's statement is a minimum figure, stated completely here:
If on the other hand, you use a desktop computer at work, and save a notebook for infrequent travel, Apple recommends charging and discharging its battery at least once per month.
For those using their battery on AC power, as opposed to someone saving a notebook for infrequent travel, AppleCare recommends the statement in the Battery FAQ.
 
Last edited by a moderator:

GGJstudios

macrumors Westmere
May 16, 2008
44,419
756
And if that minimum was actually bad for the battery it wouldn't be a minimum. :rolleyes: Stop spreading FUD please. The battery is nothing more than old.
It's not FUD. It was a recommendation and it's a valid one, whether you agree with it or not. I didn't say it was bad for the battery.
 

samh

macrumors 6502
Oct 29, 2009
317
3
And if that minimum was actually bad for the battery it wouldn't be a minimum. :rolleyes: Stop spreading FUD please. The battery is nothing more than old.
It depends how those 36 cycles were acquired.

Anyhow, if resetting the SMC doesn't work a new battery is in order. Batteries fail, it's just part of life with electronics.