Understand the LEDs
The PiZ-Uptime and Pi-UptimeUPS comes with multiple LEDs to help you fathom what’s going on. There’s an orange LED that indicates the battery level. This starts off practically invisible, but glows brighter as the battery level drops to provide you with an early warning system. You’ll also find a small red LED that lights up after the hardware reset switch has been pushed to indicate the power reboot sequence.
Three more LEDs can be found along the side. The blue LED will light up when running on battery to indicate low battery (under 3V of power). The green LED indicates mains power is connected – when it is, the blue LED switches function to indicate that the battery is being charged. When charging is complete, the yellow LED lights up instead.
It’s possible to disable these LEDs using a jumper on the board, which can save you a bit more power. Of course, this might be practical if you’ve connected the board via the GPIO pins and have the shutdown scripts in place. If you’re forced to connect the PiZUptime to your Pi using the supplied micro USB cable, you’ll need to shut down the Pi Zero manually in the event of power failure, which might be an issue if – for example – you suffer a power cut and you have no network access. Thankfully, choose a reasonable battery and you’ll have plenty of time to get things running again before panic need set in.