Preview: CEMM update 1.16 - battery

In this third preview for CEMM update 1.16, we look at the improved battery support, including the calculation of electrical usage and the improved energy flow widget.

Battery meter

A battery is easiest to monitor using a Shelly plug, Shelly kWh meter, or Modbus meter placed between the battery and the circuit to which it is connected. By measuring how much the battery (dis)charges, the CEMM can correctly calculate the actual usage.

In some cases, it is also possible to read the battery directly, for example via Modbus or MQTT. The advantage is that the CEMM can then also track the state of charge (SOC) and that no additional meter is needed. However, this is not possible with all batteries and always requires a custom configuration.

Energy flow widget

One of the places where you see the effect of the battery is in the energy flow widget. We have expanded this widget with a variant that displays the battery and also shows the import and export from the smart meter side by side. Does the battery meter also measure the state of charge? Then this is displayed as well.

Energy flow widget with battery

Have you created a battery meter, but are you still seeing the triangle version of the widget? Then two things could be the case:

  1. The dashboard has been configured manually. You need to select the battery meter in the widget settings and save the dashboard.
  2. The meter does not have the battery role. Go to the meter settings and select the correct role.

Electrical consumption & battery role

Below the smart meter, you will find two channels: electric usage power and electric usage energy. These two are calculated based on the smart meter, any production meters, and, since update 1.16, the battery meter.

It is important to assign the correct role to the production and battery meters so that the CEMM can use the meters in the electric usage calculation. To support the battery, we have therefore added three new roles:

  • "battery", this is the standard option and the right choice in almost all cases.
  • "battery-total", use this if you are measuring both individual batteries and the total. If you use this role for the total meter, it is used instead of the sum of individual batteries.
  • "battery-virtual"; you use this role if you want to mark the meter as a battery but do not want it to be included in the calculation.

The formula without a battery is: 

usage = import + production - export
With a battery, the formula is:
usage = import + production - export - charge + discharge

Do you have multiple production or battery meters? Then these are added together; the formula remains the same.

Continue in update 1.16

Check out the previous previews regarding dynamic pricing and a number of handy new features. We will soon post a news item with the full changelog and roll out the 1.16 beta update. The full rollout will follow a few weeks later. Keep an eye on this website for more information.