The mUPS is a PoE injector with battery backup capability with a 12 V battery connector. It works just like a Gigabit PoE injector, but when power is lost, it switches over to the 12 V battery. Even if your power source is 28 V, the connected RouterBOARD will not reboot when the power source is lost, it will
switch over to the 12 V battery transparently. The LEDs indicate DC line or battery usage, the charging of battery and low battery level (<50%).
In RouterOS it is possible to detect when running on battery power by monitoring the input voltage with scripting, since the voltage will change without a RouterOS reboot.
The mUPS is a simple and compact device to make your network more reliable, or for situations where stable power input is not available, like solar or automotive installations. You can use the mUPS with any single 12V battery (AGM, Gel, Lead Acid, regular car batteries, deep cycle marine batteries, etc.).
When input 12 - 24 V = 24 V
When input > 24 V = same as input
When powered by battery = 20 V