Energy monitoring devices

For a research project we are monitoring multiple locations with different settings. Sometimes only a power plug is monitored, sometimes a whole house at the house distribution.

We were looking at different existing platforms which are not relying on a cloud solution. Shelly does a great job with this, and it also allows to flash different firmware by having quite a nice API.

Yet the default firmware does not show apparent power and reactive power. Flashing Tasmota on those plugs helps here to get better insights.

In the Shelly Firmware it is quite hard to set a proper name which is used for the MQTT connection. But somehow I also managed to this.

Shelly Plug S

This is a very small device which is plugged into a normal power plug (SchuKo-Steckdose) and can be connected to your home Wifi. One can either use the shelly cloud for less technical people or use a custom MQTT broker

Shelly Plug (without S)

The Shelly Plug, while being the older device, does allow a higher power consumption with up to 230V/15A. This is a little more than the Plug S with 10A, which can be very useful in some places. On the other hand it is much bigger and not that aesthetic compared to the Plug S

Shelly 3EM

For roughly 100€ the Shelly 3EM is the best device to measure energy usage of three phases in a household or for a smaller PV.

Notice that the device does need 3 connected voltage cables for each phase, as it does not use the resulting voltage to calculate the power consumption but multiplies it with the amplitude of the phases which results in wrong values if only one voltage is used.

The device can be flashed with Tasmota too but I did not try that out yet.

Config for Telegraf and MQTT

To visualize the results, we did set up a public grafana which is available here:

This is quite spectacular because shelly devices, tasmota devices and SmartPis are integrated in the same way and can be shown in the same graph because of a useful telegraf configuration. The telegraf configuration can be seen here: https://github.com/bc4p/smartmetering/

So that this monitoring is a plug and play solution for various different devices.