Why can my uninterruptible power source handle an entire workstation and 4 monitors for half an hour, but dies on my toaster in less than 30 seconds?

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Lost power today. My toddler wanted toast during the outage so I figured I could make her some via the UPS. It made it all of 10 seconds before it was completely dead.

Edit: I turned it off immediately after we lost power so it was at about 95% capacity. This also isn’t your average workstation, it’s got a threadripper and a 4080 in it. That being said it wasn’t doing anything intensive.
It’s also a monster UPS.

Edit2: its not a TI obviously. I’ve lost my mind attempting to reason with a 2 year old about why she got no toast for hours.

In: 2145

15 Answers

Anonymous 0 Comments

Batteries like those in the UPS are rated in Amp-hours, meaning the ability to deliver X amount of Amps for an hour of operation.

If the UPS is rated for 1 amp hour, it can provide 1 amp for an hour, or .5 an amps for 2 hours, or 2 amps for 1/2 an hour and so on.

The average toaster uses 8-10 amps, while a computer uses anywhere from 1/2 an amp to 5 amps depending on what you are doing. So a toaster will empty a UPS far more quickly than a computer. So if a UPS can run a computer for 30 minutes, it can probably only run a toaster for less than 5 minutes.

In your case there’s a pretty good chance you had already drained it a significant amount as well from using it with your computer.

Producing heat for the sake of producing heat is very energy intensive and to heat up toast a toaster must draw a lot of power to heat up very quickly.

The catch is over an hour of normal operation a computer will use a lot more electricity, because a toaster will only run for a couple of minutes while the PC runs continually.

Printers are also notorious for burning through a UPS because a laser printer is basically a big heater.

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