Can you use an old Mac laptop without a battery?

A Macworld reader has a perfectly good 2009 MacBook Pro–except for its swollen lithium-ion battery. He wants to keep it on hand for limited uses after safely removing and disposing of the battery. Is there a downside to working battery-free?

Not really. As long as you’re always plugged in, a Mac laptop has no idea about or interest in whether it’s drawing power from a battery or a wall outlet. Years ago, I used a hand-me-down iBook like this (in the era in which you could just pop out a dead battery, as they were removable) so my kids had a machine to work on when they were little.

Of course, the big problem is that any power discontinuity means that the Mac shuts off instantly. Hard drives used in older Mac laptops can suffer from an instant power off but are typically okay as long as the machine isn’t being moved around. Any work in progress that’s not saved is lost.

Our reader is savvy about this, however, and has already planned the right complement to a battery-free Mac laptop: an uninterruptible power supply (UPS). You don’t need a model with a lot of battery capacity, as you’re just trying to buy yourself a moment or so to save and shut down in the event of a full-on power outage. In most cases, the UPS helps the Mac over any minor hiccups that would cause it to crash or restart.

Update: Some readers have reported having problems using a Mac laptop without a battery, as, in certain conditions, a Mac may require a temperature sensor that’s part of a battery to judge overall system heat. When missing, macOS can interpret that as the computer overheating and slow the process to a crawl. If you experience that problem, consult this StackExchange thread that has links and information across many generations of Macs.

This Mac 911 article is in response to a question submitted by Macworld reader Tom.

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