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Comment by chipotle_coyote | Hacker News Reader

I don't think I've ever seen that behavior with a MacBook Pro of any vintage -- and I've had an MBP of one stripe or another since at least 2007, using the date of the 2007 MacBook Pro gathering dust bunnies nearby -- except when I use the wrong power supply with it, e.g., a 13" MBP power supply with a 15" one, or my MacBook Air's power supply with any MBP now.

I wouldn't doubt it's possible to draw more power than the adapter can give you if you're pushing the MBP full-bore, but I'm pretty sure that under normal power loads, this doesn't happen.

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Try mining cryptocurrency, running prime95, playing fps shooters, or even dota on high settings. You will notice the battery draining while plugged in. You also see it if you are on an airplane, but that is usually because the charger tries to pull too much and overheats and gives up ghost. Macbooks have underpowered chargers.

> Macbooks have underpowered chargers.

My 16” shipped with a 96 watt charger, and I’ve not seen a laptop with a higher powered one. I’d have to contend with that assertion.

I had 180W for my old HP laptop, and recently ~135W (or 170W) for Thinkpad W541.

<100W adapters were mostly for potato laptops, until USB-C came into picture which supported up to 100W and now manfucaturers adapted (and probably wait for 200W PD).

Newer Dells pull 180W from a paired USB-C dock connector.

Nice to see workarounds.

I must say that I love that I just plug out the laptop power adapter and plug it into my phone (or mouse) and it charges. Even when it comes with lower performance of the laptop.

Are all other laptops you've seen potato? My Dell XPS 15", 130 watts.

My current Dell laptop uses a 240 watt charger

ThinkPad P73 has 230 Watt charger.

I suspect that this is the reason why MBPs now refuse to boot on low battery. You used to be able to start up the machine when your battery was at 0% (as long as you were plugged in), but newer MBPs complain and don't boot up until you recharge to 10% or so.

They just bumped the power adapter on the 2019 MBP up a little bit. I've seen people say that if they max all cores and leave it that way it will drain the battery even if it's plugged in. I haven't attempted that, and I've never seen the behavior under any other circumstance.

I've run into it a few times with mine (2017 15" MVP, 3.1GHz Quad i7, 16GB RAM, Radeon Pro 560). I had an issue the other day where a virtual machine got stuck in a loop while testing some background jobs. Each time I tested it, another infinite job booted up. Eventually, I had like 30 of them running when I took off my headphones and heard the fans. Checked my battery and I was down to 65% despite being plugged in. I'm guessing that happened over the course of an hour or so.

I've also had it happen a few times when running unit tests for a different project in Docker, but that's likely just because Docker for Mac makes Electron look resource efficient.

It does, just launch any game that uses 3D (tried Starcraft 2 and WoW) - you will see that battery will drain when you have power adapter plugged in - MacBook Pro from (AFAIR) 2018.

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