Unibody MacBook Pro models with 13" displays produced from 2009-2012.

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Battery is empty at ca 18%

Hej all together,

I've a huge problem with my changed iFixit Battery.

I can't reset the battery properly. This means even if I have 15-18% Battery left my MacBook Pro shuts down immediately. Not very nice at all.

What I've tried was following the Apple advice, to empty the Battery and wait and the recharge it... Did it a couple of times.

2nd what I've tried was to reset the SMC, doesn't work either.

One small note. The LED from the charger doesn't work properly from time to time. And when my MacBook is open and I try to put it into sleepingmode it wakes up after a few seconds. Maybe this does help (I haven't a clue).

If you need further information just let me know (or any translation)

I'd be grateful if there is someone who has a idea :)

greets, Jonas

MacBook Pro 13" Mid 2010

Informationen zum Batteriemodell:

  • Seriennummer: D
  • Hersteller: SMP
  • Gerätename: bq20z451
  • Pack Lot Code: 0
  • PCB Lot Code: 0
  • Firmware-Version: 74
  • Hardware-Version: 00aa
  • Zellen-Version: 2

Informationen zum Ladezustand:

  • Verbleibende Ladung (in mAh): 1656
  • Vollständig geladen: Nein
  • Batterie wird geladen: Ja
  • Volle Ladekapazität (in mAh): 6261

Informationen zum Batteriezustand:

  • Anzahl der Zyklen: 72
  • Zustand: Gut
  • Batterie ist installiert: Ja
  • Stromverbrauch (in mA): 2885
  • Spannung (in mV): 11734

Update (25.04.2017)

I cleaned the port and bought a new cable. But, I still have the issue.

I saw that during the loading process the Battery charge jumps from 81% to 100%. Until now I saw it only once.

Update (27.04.2017)

Here is a screenshot of coconut battery

current life data:

Block Image

History (looks not good to me, that the capacity increases):

Block Image

Answered! View the answer I have this problem too

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Download this gem of a free app: coconut Battery It will report the status off your battery & charging. Paste a screenshot of the main screen so we can see all of the info.


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@xco Hi Jonas,

Can you tell us your usage pattern. Do you tend to travel running the system on battery until it has exhausted? Or, are you using your system mostly tethered to the MagSafe charger?

Why I ask is for such a young battery you have already pushed the cycle count to 111. The status of the battery & charging looks healthy otherwise.

The only thing I suspect here is you weren't able to get the system to reset the SMC for some reason. Here's the Apple T/N: Reset the System Management Controller (SMC) on your Mac

I'll let you in on a secret ;-} Even I've had problems getting it to reset if I rush it.

You see, the trick is to full discharge the system so the older setting is forgotten. There are two pieces that need clearing the logic board and the battery its self as it has a chip onboard as well. So you need to hold the keys & power button a good 15 seconds (longer than what the TN states). Don't forget to first fully charge the battery (overnight) then do the SMC reset, then fully discharge the system (I run a script doing a heavy action over and over again to speed this up a bit and I have it save the count of cycles). Then I recharge the battery (overnight) and then run my script again. But this time I review the counter it needs to be within the same value I've listed for the given series if not I'll put in a new battery and then repeat this process again.

What have I learned... First not all battery suppliers have good products! I've gotten a few defective batteries even from our trusted source. Sometimes it's the system not the battery, either the MagSafe connector or the logic on the system board.

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Hej, thanks for your long answer!

Honestly I don't know why the battery has so many cycles... But i gues due to the fact, that I'm working in many different locations during a day ( I'm a student) I'm quite often running on battery. With running some really small computations my CPU take a lot of energy and that could be the reason for the 111cycles... So on a long day my laptop runs for about 10h and one battery charge lasts maybe only 4h or less depending on what I do.

So basically what you mean is, that the only thing that i can do is to reset the SMC with your recomendation and hope that this will fix the problem, otherwise I have a bad battery.


I have purchased many batteries from many different sources and haven't found many that last 4 hours for this model. I would think based on autonomy only that it is a good battery.

However, shutting down at 18% is a reporting error. I would try to reset everything like Dan said and see if things improve.


You may need to review your systems process load. You could have some malware or P to P application running which is running your system down. Think of it this way your cars gas tank has a hole in it so slowly your fuel is leaking out so you can't go as far.

The other factor is what you have running as well. You can't expect to have a low electric bill if you leave everything running all of the time. Here we need to reduce the process load of applications running in background.

See if you can locate whats running using Activity Monitor and install antivirus & malware apps to make sure you don't have anything else running that shouldn't be.

Also think about what you are doing while you're on battery. Don't be wasteful and make sure your systems energy settings are set to conserve power.


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You said the charger light doesn't always work, do you have a spare charger to test it? That could be your problem

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It works not always. Only sometimes the LED is not glowing.

So you mean doing the battery reset with a diffrent charger could help. When it works afterwards I need to replace the old charger.


You also may have a dirty or damaged MagSafe port or cable. Using a cotton swab (Q-Tip) slightly damp with 85% isopropyl alcohol clean the connections on both the cord and the system. Also inspect them to make sure the contacts are in good shape. Here's a good Apple T/N to review: Apple Portables: Troubleshooting MagSafe adapters


I think you have a bad battery or it has gone bad and not reporting % properly. How long have been using it?


I'm using it for ~9month.


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xco will be eternally grateful.
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