Hi all, What is UPS input load and how can that affect the power draw of devices plugged into it?
Context: I have an Eaton UPS. Into it I plugged TP Link smart plug to measure how much my homelab draws (1 truenas server, 1 rpi and a switch). These draw about ~29 W when under low to medium load. Almost every day (different time) for couple of hours, however, the plug measure about 6-7 Watts more (~36 W). I have checked both linux devices and they were doing basically nothing. Then I looked into TrueNAS monitoring and noticed that the start and end of each event is exactly the same time when UPS input load is increased from 0 % to ~6 %.
What is this UPS input load and how is it possible it affects measurements by a device that is plugged into it (the UPS) - NOT the other way around? Thank you
The UPS needs some power to keep its batteries full. Could be that it’s triggering off some threshold to do a charge cycle instead of just running a constant trickle. I’ve noticed that my laptop and phone charge that way, for example.
But the TP link that measure the power is plugged into the UPS not the other way around. The UPS is directly in the wall plug.
The UPS has no influence in that case on the power reading.