Using battery pack as a UPS

Question

I need to use raspberry devices as mini servers. I'll need to install ~100 of them in different locations. In those areas, electricity power offs are quite common, so I'm thinking using a cheap usb battery pack as a UPS. I'm considering http://smile.amazon.com/KMASHI-Thunderbolt-Incredible-Blackberry-Smartphones/dp/B00JM59JPG/ref=pd_sim_cps_9?ie=UTF8&refRID=0NGYHENZXAX3Q2C5RD22 this or http://smile.amazon.com/Poweradd-trade-Pilot-X1-Flashlight/dp/B00DGJJNVO/ref=sr_1_16?ie=UTF8&qid=1406750103&sr=8-16&keywords=usb+battery+pack this.

My questions is:

• Will this approach work at all?
• Is there any way I can detect when power goes off?

Thanks.

Answer 1

Despite many horror stories the Pi is quite reliable. Mine run for months at a time, and many others have similar experiences.

If I was to do this, I wouldn't bother about detecting when power goes off; just power the Pi from the battery (via GPIO pins or µUSB power) and run the battery on a float charger.

Depending on your project you may need to take other steps. No computer is 100% reliable, and the Pi uses a SD card - which is NOT recommended by manufacturers.

You may need to implement a watchdog timer, commonly used for remote systems. The Project Curacau article discusses some of these issues. See http://www.themagpi.com/issue/issue-21/

Answer 2

If you need to run any additional equipment, such as external drives, sensors, etc. then you can use a standard, off-the-shelf UPS, and the Network UPS Tools (NUT). I have just posted an article I wrote with step-by-step instructions for setting it up:

https://melgrubb.wordpress.com/2014/09/05/raspberry-pi-home-server-part-15power-failures/

Answer 3

I don't think so - it seems that both of those devices do not do "pass-through" charging - i.e. provide an output whilst charging themselves. Of course another name for such a device would be a Uninterruptable Power Supply (UPS) - though there could be also a difference if the devices also have a "time-limit" when providing an output, which is not what you want...!

Answer 4

This battery pack works extremely well as a USB-based UPS: ZMI PowerPack Ambi 10000mAh https://www.amazon.com/gp/product/B07N7ZQ68Z

You power it via a USB C charger. You use the other port (via a USB-C<->Micro USB cable) as the power supply for the Pi. When the power pack gets or loses power, I can confirm it does NOT reboot the Pi, which is what many of the other battery packs do.