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Can I disconnect a (shot) MacBook 12 battery and use it just plugged into the wall

F

fishes234

macrumors newbie
Original poster
Mar 25, 2011
14
2
As the title thread: I’ve got a 2016 MacBook with a knackered battery (won’t charge fully and lasts barely 40 minutes when disconnected from the wall).

Looking at Ifixit, disconnecting the battery looks quite straightforward and I was wondering if I could use the laptop with the battery disconnected, just plugged into the mains? Looking at the cost of a new battery, it hardly seems worth doing and I was planning on retiring it to a corner of the house for use as a file server and to run our CCTV cameras (to replace an ageing desktop). Given the battery’s condition, I’m a bit hesitant about plugging it in somewhere out of sight, where I wouldn’t notice excess heat and any battery swelling!
 
If my memory is correct, I believe the Mac requires a battery to be connected if it you always use it plugged in. I don't believe it will boot properly without.

If I am wrong, someone please correct me.
 
Yes, my spare 2010 MacBook air battery swelled up Thursday
and works perfectly now without the battery
 
I don't know if it's still the case. As I recall they'll work but at a reduced performance.

You can always get a cheap battery with good reviews off Amazon.
 
fishes234 said:
As the title thread: I’ve got a 2016 MacBook with a knackered battery (won’t charge fully and lasts barely 40 minutes when disconnected from the wall).

Looking at Ifixit, disconnecting the battery looks quite straightforward and I was wondering if I could use the laptop with the battery disconnected, just plugged into the mains? Looking at the cost of a new battery, it hardly seems worth doing and I was planning on retiring it to a corner of the house for use as a file server and to run our CCTV cameras (to replace an ageing desktop). Given the battery’s condition, I’m a bit hesitant about plugging it in somewhere out of sight, where I wouldn’t notice excess heat and any battery swelling!
Click to expand...
The computer will run at no more than half speed without a battery installed so you'll likely find performance to be quite unsatisfactory.
 
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Thanks all. That’s a real shame about underclocking when the battery’s not connected: I wonder why, perhaps to do with the battery providing a regulated supply, or some sort of protection mechanism? I might give it a try and see how it works - running the CCTV cameras doesn’t need a lot of horsepower.

I had a look at batteries on Amazon, but most of them on the UK site have pretty poor reviews and batteries is one thing I’m very wary about. Usually I’d go to Ifixit as their stuff’s alway been pretty good, but I think they dispatch from Europe and I’d likely get stung by a large, unspecified import tax!
 
fishes234 said:
Thanks all. That’s a real shame about underclocking when the battery’s not connected: I wonder why, perhaps to do with the battery providing a regulated supply, or some sort of protection mechanism?
Click to expand...
It is because at times of heavy load the computer will draw from the battery even when connected to the AC adapter.

I would not buy a 3rd party battery for any computer where it's still possible to get a new one from Apple. The quality varies too widely and lithium rechargeable batteries can and do occasionally explode and/or catch fire. That risk just isn't worth it for me.
 
chrfr said:
It is because at times of heavy load the computer will draw from the battery even when connected to the AC adapter.

I would not buy a 3rd party battery for any computer where it's still possible to get a new one from Apple. The quality varies too widely and lithium rechargeable batteries can and do occasionally explode and/or catch fire. That risk just isn't worth it for me.
Click to expand...

It's a shame Anker stopped providing batteries. Those were every bit as good as OEM. Perhaps better. I've got two different Macbooks with Anker batteries. So far the replacement batteries are still good. Those replacements are older now than the OEM batteries were when I replaced them. I also replaced batteries on many customer laptops with Anker. Never heard a complaint.
 
Just to follow up, I ended up going to a local phone shop that I've used for iPhone battery replacement a few times and they replaced the battery for £160 - obviously it's not a geniune battery, but it seems fine and the reported capacity is roundabout the original.

I think what's goosed the battery is having it connected to a dock with a big monitor and keyboard most of the time - my other half's got a slightly newer MacBook and the battery's fried in that too, since she's been teaching from home during the lockdown with the computer plugged in all the time. Whilst the newer MacBooks do battery management, I guess the battery charge level is managed at a low level (presumably in the SMC?) and there's nothing you could do to stop it charging past 80%, other than unplugging it. I seem to recall that you could tape over one of the pins of the old MagSafe charger, so that it would provide power to the Mac, but not charge the battery. I would be great if you could get a usb c cable with a switch in it that cut the charging circuit, but still allowed data through - I've seen similar for Raspberry pi, but think it's effectively just a power cable.
 
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fishes234 said:
Just to follow up, I ended up going to a local phone shop that I've used for iPhone battery replacement a few times and they replaced the battery for £160 - obviously it's not a geniune battery, but it seems fine and the reported capacity is roundabout the original.

I think what's goosed the battery is having it connected to a dock with a big monitor and keyboard most of the time - my other half's got a slightly newer MacBook and the battery's fried in that too, since she's been teaching from home during the lockdown with the computer plugged in all the time. Whilst the newer MacBooks do battery management, I guess the battery charge level is managed at a low level (presumably in the SMC?) and there's nothing you could do to stop it charging past 80%, other than unplugging it. I seem to recall that you could tape over one of the pins of the old MagSafe charger, so that it would provide power to the Mac, but not charge the battery. I would be great if you could get a usb c cable with a switch in it that cut the charging circuit, but still allowed data through - I've seen similar for Raspberry pi, but think it's effectively just a power cable.
Click to expand...
Same happened with mine, 2015 MB - always connected to power and running monitor, ext drives, Ethernet. Traded in for 2020 Mini which is a better fit for me - Apple offered $240 so win-win on 5 yr old MacBook.
 
Amethyst1 said:
I guess it's because at full speed and load, the system might draw more power than the charger alone can provide, so it would crash without the battery.
Click to expand...
That can happen for example if your hard drive was sleeping and turned on, while your Mac used a lot of power. Maybe just for a second more power is needed than the charger can give. Even the worst possible battery will handle it, but no battery at all won't and your Mac can crash.
 
fishes234 said:
Just to follow up, I ended up going to a local phone shop that I've used for iPhone battery replacement a few times and they replaced the battery for £160 - obviously it's not a geniune battery, but it seems fine and the reported capacity is roundabout the original.

I think what's goosed the battery is having it connected to a dock with a big monitor and keyboard most of the time - my other half's got a slightly newer MacBook and the battery's fried in that too, since she's been teaching from home during the lockdown with the computer plugged in all the time. Whilst the newer MacBooks do battery management, I guess the battery charge level is managed at a low level (presumably in the SMC?) and there's nothing you could do to stop it charging past 80%, other than unplugging it. I seem to recall that you could tape over one of the pins of the old MagSafe charger, so that it would provide power to the Mac, but not charge the battery. I would be great if you could get a usb c cable with a switch in it that cut the charging circuit, but still allowed data through - I've seen similar for Raspberry pi, but think it's effectively just a power cable.
Click to expand...

What you should do is discharge your MacBook once a month, not more, if it is permanently plugged in.
 
after years of experimenting with apple products and random brand batteries, going forward id just pay apple to do the job and move on with life. getting a discount on a random battery only to find out it fails months later or causes device issues due ot apple messing whith the OS isn't worth all the effort and surprises.
 
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petsk said:
You can install AlDente and limit the maximum charge level to whatever percentage you want. Set it to 50% if you are always plugged in.
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That is amazing. I gave up looking for something that would do this years ago - everything I've read about battery management suggested that it was buried so low down in the SMC firmware that it couldn't be got at. I've been trying this for a few days and using the Classic SMC setting it just seems to charge up to the set level and then pretty much runs off the mains cable with no battery cycling at all. It's perfect - thank you!

I get the arguments for going for genuine Apple batteries, but I'm probably going to get something newer in the next couple of years and the laptop's, er, 'well used', so I don't think would attract a big resale value. Given that I can now run it off mains permanently without trashing the battery, I'll likely retire it to running our CCTV and as a file server when the time comes...
 
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