RB912 voltage measurement deviation

Hardware MikroTik hardware general
1

Hi all,

I’m monitoring a couple of solar-powered RB912s, and it seems the voltage measurement shown in System → Health is always lower than the actual DC voltage provided by the battery, by around 0.9V.

Does anyone know if the DC voltage measurement is taken after a protection diode, or other circuit that would cause this voltage drop?

Is there a difference in how voltage is measured with the RB powered through the DC jack vs. passive PoE?

Thanks!

2

The voltage measurement is very approximate. Do not take it as an accurate measurement instrument.

3

Thanks normis - not intending to use it in a scientific way, but I’d like to use it to notify someone if the batteries are running down to dangerous voltages, eg. if solar panels stop working, are blown down by wind or whatever.

Is there a circuit diagram of the RouterBoards available?