These Switches are mainly powered by a power supply, but to prevent power failures we have also added a battery block.
Normally when the power supply is running, the switch is powered with 58V input. If something happens which causes a power failure the switches are powered by the battery block. The Battery Block provides 51 V when they are full. The emptier the battery block the lower the voltage.
Normally the switch should fit with 9 to 60V, but in our case the switch just shuts down when the input voltage is below 48V.

We monitored the input voltage, in this picture you can see how it looks like in prtg.
At 3pm the power supply does not work eg. caused by a power cut. The Battery provides ca. 51V.
At 4.30 the switch turns off, and the last voltage it gets is 47.83V
As you can see, the voltage drops faster at ca. 4.20pm, maybe switch can not fit with a bit faster voltage drop?