Lets say the battery has over 5000 cycles and is almost dead or dead. If I will use this notebook always with power adapter - is at dangerous in any way?

I mean - is it possible that the old battery will explode etc.?

Its MacBook Pro 2015 so it cannot be removed.

  • No there is a reason phones and laptops are recalled.
    – William
    Jan 27, 2017 at 17:26
  • @William - I mean the probabilty of the old battery to explode or to caught fire.
    – MikroDel
    Jan 27, 2017 at 17:38
  • @William it is also sure that any vendor (Apple, Acer etc.) will advice to replace the battery. But its about money.
    – MikroDel
    Jan 27, 2017 at 17:39
  • Then remove the battery. No vendor I know says the battery should be removed because of exploding issues even when old. There is probably a pass through on the laptop such that this is not an issue. I don't believe the FDA would approve something that has the potential to explode even when old.
    – William
    Jan 27, 2017 at 17:44
  • 1

2 Answers 2


Short answer:


Medium answer:

There is always a risk of something failing in a fantastic way, but the chances of a deadly situation are slim to none if the user is taking good care of their hardware (no frayed cords, no liquids near electronics, etc.).

Long answer:

Simply put, batteries are arrays of cells that consist of sandwiches of two metals and a chemical between them. The reaction draws electrons from the negatively charged side of the cell, through the electronic device's circuitry, through the positively charged metal into the chemical compound, which eventually becomes saturated as the first metal's electrons are drained.

Recharging reverses this process, but flaws develop in the first metal's surface, causing it to resist or refuse additional inbound electron flow. Eventually, the battery becomes unable to accept a new charge and has nothing left to give.

The battery's circuitry and charging circuitry have failsafe mechanisms to prevent shorting the battery (which can result in an explosion if there's enough current stored), shorting--and subsequently frying--the charger's power supply, and all the fun stuff in between. With all of that safety equipment in place, it essentially means your battery's nothing but a brick that the charger refuses to touch.

So no, it is highly unlikely to explode.

All that being said, I have had old batteries swell and expand...

Check ifixit.com for what it would take to replace your laptop's battery, when the time comes.

  • 1
    I would add a warning to this answer. The battery is glued down, so attempting to remove it could be dangerous and cause the battery to catch fire or explode. Apple will replace these batteries at the relatively low cost of $200 (plus tax - note that the battery alone would cost ~$100)
    – NoahL
    Jan 27, 2017 at 23:02
  • And with the newer MacBooks and other devices that will inevitably come out with the terraced cell structure, self-replacement is a thing of the past. I have not had experience with 2015's, but I have not had a hard time working with other unibody MacBook Pro's. Jan 29, 2017 at 3:42

Adding to the very good answer from SirBryan, you should keep in mind that MacBooks also use the battery as a buffer. That means there can be situations, e. g. when the GPU and CPU are under full load, where the power adapter simply does not deliver enough energy. They are designed in a way that they cover 95% of all load situations.

So, once your battery is completely dead, the Mac has no choice but throttle the CPU to avoid peak power draw and therefore power failure. You are likely to notice a considerable performance loss at some point.

  • 1
    Why the downvote?
    – n1000
    Jan 28, 2017 at 12:07
  • I voted up :) I don't know the reason of downvote too
    – MikroDel
    Jan 28, 2017 at 12:08

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