If you put a bunch of computers in charge of your house, it’s generally desirable to ensure their up-time is as close to 100% as possible. An uninterruptible power supply can help in this regard. To that end, that’s why [Bill Collis] whipped one up for his Home Assistant setup.
[Bill]’s UPS is charged with one job—keeping the Home Assistant Green hub and an Xfinity XB7 cable modem online when the grid goes dark. The construction is relatively straightforward. When the grid is up, everything is powered via a Mean Well AC-DC 12 V power supply, while the power is also used to charge a 12.8 V 10 Ah lithium iron phosphate battery pack. When the grid goes out, the system switches over to running the attached hardware on pure battery power. A Victron BatteryProtect is used to automatically disconnect the load if the battery voltage drops too low. Meanwhile, a Shelly Plus Uni module is used to monitor battery voltage and system status, integrated right into Home Assistant itself.
If you want to keep the basics of your smart home going at all times, something like this is a pretty simple way to go. We’ve featured some other great UPS builds in the past, too. If you’re whipping up your own hardware to keep your home or lab alive in the dark of night, don’t hesitate to notify the tipsline.