I have a MacBook Pro 15" from Mid-2015. Unfortunately the battery started swelling up (funnily the battery menu claims the it to be ok).

Since it's a stationary computer after I smashed the screen I simply want to run it without battery.

As soon as I remove the battery it does not boot anymore. It starts booting but then before it gets to the login screen it turns off again.

There is absolutely no information on this issue on the internet. The only hint I could find was another person claiming the AC adapter wouldn't have enough grunt to handle boosting.

That does not make a lot of sense to me, since I ran MacBooks without battery numerous times. On the other hand it's a pretty sound theory, electronics wise.

Is there any possibility to reduce load on boot? I could also try to sacrifice an old AC adapter and solder the MagSafe to either a thicker cable or even to a different power supply...

Any thoughts on this? Could it be, that the AC adapter is not capable of providing enough power (85W though...)? Or could the wimpy cable introduce too much voltage drop?

2 Answers 2


The 85W power supply should be able to supply enough power, and the problem is unlikely to be resistance in the cable.

It has been observed here and elsewhere that removing the battery on many models of MBP causes severe CPU throttling.
Can MacBooks run without a battery??

However, there should at least be enough CPU to boot, so it's possible that you have some other problem. Perhaps the onboard power management itself is faulty? Or maybe some sensors are damaged?

So, with a smashed screen, no battery, faulty internals...

  • I see where you're coming from. Unfortunately I have to keep the thing alive just a little longer... But thanks. That points to things like the power management being faulty. Would also explain the battery failing in the first place Commented Jan 17, 2021 at 18:35
  • 1
    Nope, the user has same problem. The MBP 2015 is designed not to be able to run without battery. Replacement solves all problems. Disconnecting battery -> cannot boot at all because by disconnecting battery the circuit is not closed.
    – Marek H
    Commented Aug 15, 2021 at 21:54

I wouldn't solder a new cable as you may risk destroying the entire Mac. It would be best to just buy a replacement battery. They're around $50 on eBay, but that's a whole lot cheaper than a new Mac if the DIY power cable fries it.

  • How could I fry the Mac by using a non-Apple Power supply? The issue is not my capability to solder or my ability to understand electronics. I'm wondering why the Mac does not boot without the battery. Sure, I can buy a new battery. Commented Dec 13, 2020 at 3:17
  • Oh ok. If you know what you're doing with electronics, then sure! I guess I misinterpreted the question. I thought you were looking for a solution to a MacBook not booting without a battery. If you want me to delete my answer, as it doesn't answer the question, just let me know.
    – Salocor
    Commented Dec 13, 2020 at 3:28
  • No! Thanks for your input! I wrote "Any Thoughts" wich may not have been wise on my part. I was thinking of "Apple has a chip in the batteries since 2014" or similar... But very well be the strange cuurent thing, dunno. Just want to understand the root cause :) And for other people that might be the right answer! Commented Dec 13, 2020 at 3:33
  • Alright sounds good! :) That is strange though...
    – Salocor
    Commented Dec 13, 2020 at 4:01

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