Apple Studio Display "Overpowered" Big UPS...

[eRondeau]

Weird situation posted as an FYI as much as anything else.

I have a M1 Mac Mini (base) connected to an Apple Studio Display. Both have been trouble-free. I got home from work at 6am today and turned on my MM/ASD to check email. Used it for about an hour, no issues. Put it to sleep (via  Menu) and went to bed, nobody else home. Woke up about noon and could hear a weird alarm noise. Checked and it was coming from my CyberPower 850VA UPS. I checked its LCD display and it was an "Overpower" warning, meaning something connected drew too much current. The UPS equivalent of blowing a fuse or tripping a breaker. I've got a couple of other small devices connected (printer, Windows laptop, small LED lamp) but the only thing that had turned off was my MM/ASD. There was no power outage at my house. I silenced the alarm and reset the UPS then turned the MM/ASD back on. Luckily they booted right up. No obvious signs of anything wrong. Checked the system logs via Console and logs abruptly stopped writing shortly after 9am resuming when I restarted at noon.

I cannot image a M1 Mac Mini drawing enough power to tap-out a high-capacity UPS under any circumstances. However the ACD -- maybe? Although in sleep mode it should only be drawing ~1W. Only connected to it was a small M.2 NVMe backup drive via USB-C; it's fine. I am absolutely at a loss as to what might have happened here. Although the issue apparently occurred and everything shut-down 3-hours before I woke-up and noticed it, there was no smell of anything burning or overheating. Both the MM/ASD have been working fine since noon. So I am at a loss.

Posted in the event anything like this has ever happened to anyone else, or ever does.

 

[BSoares]

How long have you had that UPS? When these things get old they tend to have some funky issues. Maybe the alert was bogus.

 

[Danfango]

Could be the ASD. It's not really a monitor. It's a very powerful power delivery system with a monitor stuck to the front of it. The inrush current when it wakes up and fires up the power supply could be quite significant, enough to trip the UPS. The best way to debug these issues is to pull the devices off one at a time until it stops happening.

Personally I just use an MBP as that has its own UPS built in (battery) and skip the external one...

 

[eRondeau]

How long have you had that UPS? When these things get old they tend to have some funky issues. Maybe the alert was bogus.

Good point... I bought it in July 2018 so it's just over 4 years old. This is the first "funky" thing that's ever happened to it, it's been rock-solid as a UPS -- but I'll keep a closer eye on it going forward. Thanks!

 

[Joestanxx]

Good point... I bought it in July 2018 so it's just over 4 years old. This is the first "funky" thing that's ever happened to it, it's been rock-solid as a UPS -- but I'll keep a closer eye on it going forward. Thanks!

At 4years it maybe time to replace the battery.

 

[eRondeau]

I wanted to resolve this thread for anyone still following it. Bonus points to everyone who said I needed a new UPS battery. The UPS totally died over Christmas (or at least the battery backed-up section). Yesterday I bought a new Lead Acid replacement battery for around $45 CDN and it is working happily once again. Any overload issue was due to the failing battery during a power outage; any power draw from my Mac Mini and Apple Studio Display was well within its normal range but the failing battery just couldn't keep up. You guys rock!