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I have used my new MacBook Pro Retina for a few days.

After three battery cycles, the battery lost capacity from 6960 mAh originally to 6616 mAh now.

Is it normal to lose almost 350 mAh of capacity in just two/three days?

  • Check the age of your battery by downloading a battery monitor app from the Mac App Store. If the battery is maybe 8-12 months old, that kind of drain could have occurred while the Mac sat on a store/warehouse shelf. – owlswipe Jun 23 '16 at 16:54
  • @John Ramos Ok, but have i any choice to deal with it? like give them the mac back or something.. – Štěpán Záliš Jun 23 '16 at 17:23
  • Well, you could replace your battery, but it's way too early for that. Check your battery's age like I said, and that will show you if your battery is defective, or just naturally old. Lithium-Ion batteries lose between 5-20% of their battery capacity every year, even if they aren't used, so it's certainly possible your battery lost 300mAh just from aging. But again, do check your battery age! – owlswipe Jun 23 '16 at 20:03
  • I can send you a link to one of the battery monitor apps in the Mac App Store that check your battery age, if you want! – owlswipe Jun 23 '16 at 20:04
  • Yes please, I have downloaded one but there is not battery age – Štěpán Záliš Jun 23 '16 at 20:06
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As per this wikipedia article,

Batteries gradually self-discharge even if not connected and delivering current. Li+ rechargeable batteries [like the kind in a MacBook] have a self-discharge rate typically stated by manufacturers to be 1.5-2% per month.

Basically, even if you are not charging or discharging your Mac battery at all, it will still lose 1-2% of its capacity every month (on average). You stated your battery age as 7.2 months, and your original battery capacity as 6960 mAh. (Side note: anyone else can find out their battery capacity, original capacity, and battery age with this tool.) Assuming it discharged 1% a month while in storage for 7 months, that means your battery could have lost 487 mAh while in storage. So, it is perfectly reasonable for your 7 month old battery to have lost 350mAh.

It is a little frustrating to have a somewhat old battery when you have purchased a new computer, but that's just how it goes. Li-ion batteries last well for about 4-5 years, so 7 months isn't too long on that scale. You will probably need to replace your Mac's battery (or get a new computer) in 2021. So, you have plenty of time to enjoy your new Mac before things even start to go downhill. But yes, that small battery discharge is normal; remember that it occurred over 7 months, not 3 days.

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    You don't need a tool to get that information. You can get it for free with the ioreg command: ioreg -brc AppleSmartBattery. If you want to filter just a particular value, pipe through grep like this: ioreg -brc AppleSmartBattery | grep MaxCapacity I don't believe in installing (especially paying for) something that already exists for free. – Allan Jun 24 '16 at 12:43
  • @Allan nice tip, but do note that that battery monitor is free! – owlswipe Jun 24 '16 at 16:06
  • I am always suspect of free apps (there's no such thing as a free lunch) especially one that has "in app purchases." – Allan Jun 24 '16 at 16:43
  • @ŠtěpánZáliš Yes, it's all ok! No worries :D. – owlswipe Jun 25 '16 at 1:53
  • @Allan You're right that it has in-app purchases but to get the required info (i.e. battery capacity and age) no purchase is necessary. There are no ads either. I do fully agree that your terminal-based approach is a good one, but I think my way is easier for people reading this answer later. – owlswipe Jun 25 '16 at 1:55

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