A couple of weeks ago, I got my hands on a UPS for a Raspberry Pi. I don’t think I ever appreciated the UPS until I started to run my own automation server. Running a custom automation server means that the server isn’t completely useless when the power supply is down. Granted, WiFi won’t be available, but your Zigbee stuff should be alright. Let’s talk UPS Pro for Raspberry Pi form 52pi.
UPS Pro HAT from 52pi
If your Raspberry Pi isn’t protected from a power loss, you are risking data loss, file corruption, SD card failure, and the obvious effects like – the stuff is not going to work. Fortunately, as soon as the power is restored the Raspberry Pi board will reboot itself. I talked about power HATs from 52pi before. And the company offers an array of HATs for your Raspberry Pi:
- Docker Pi Power Board (review)
- 4 Channel Relay HAT (review)
- ICE Tower Cooler (review)
- IoT Node (GPS, GSM, LoRa) (review soon)
- NightLigt HAT (review soon)
UPS Pro HAT from 52pi aims to fix this. The HAT is designed for Raspberry Pi 2B/3A+/3B/3B+. Despite the dimensions fitting Raspberry Pi 4B boards, the power delivery isn’t strong enough. In my tests, the Raspberry Pi 4B board would hang after some time. There is an updated version available now that supports Raspberry Pi 4 with a USB-C charging port!
Features
I actually spoke to PR at 52pi and they confirmed that a new UPS Pro HAT for Raspberry Pi 4 is being considered as well. Until then, let’s take a look at the existing functions of the UPS Pro HAT from 52pi:
- UPS based on 2 x 18650 Li-ion cells
- 4 LED charge indicator
- Unobstructed power delivery (via 5V|GND GPIO)
- Charging and power on the circuit
- 2 USB-A ports to charge other devices
- Power button
Powered by 2 x 18650 Li-ion cells the UPS Pro HAT can last up to several hours depends on the power draw of the Raspberry Pi and the capacity of the 18650 Li-ion cells.
Imperfect
Unfortunately, one important function didn’t make the cut. The UPS Pro HAT from 52pi will continue running your Raspberry Pi until 2 x 18650 Li-ion cells have the juice. Once the batteries are drained, there is no way of letting the Raspberry Pi know that the UPS Pro HAT from 52pi is running out of power.
The HAT delays the unsafe shutdown problem rather than delays it. I will play with the board a little bit to come up with a system that would shut down Raspberry Pi safely when the power is low, but this will be a subject of another write-up.
Overall
The UPS Pro HAT from 52pi can be a nice extension to your project. The extra USB ports can be used to power up SSD drives or recharge other devices and the design of the HAT keeps all the GPIO pins available for other projects.
I’d like to see cases that would actually accommodate this design as having an extra bit of juice could be the difference between collecting your data and losing it.
Conclusion
I’d be really tempted to fix the issue with battery reporting so I could get the notification when the UPS is active, receive the updates on battery levels, and be able to safely shut down the Raspberry Pi when the batteries are low. I had good luck with modding the 52pi’s Cooling tower, perhaps I will have the same luck with this HAT too. Let me know what do you think about this HAT in this Reddit thread.
