Booting MBP 15" 2015 without battery

Question

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?

Answer 1

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...

Answer 2

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.