Unexpected riemann integration results

Configuration
1

I am using the following integration template to generate a power chart from an energy sensor:

sensor:
  - name: Battery Energy (Sungather)
    platform: integration
    source: sensor.inverter_battery_power
    unit_time: h

sensor.inverter_battery_power is an MQTT entity, which appears to be functioning correctly. However, the integration values are hugely negative and trending downwards over time. Here is a statistics graph of both:

batterypower

My understanding of calculus is very rusty, but my intuition is that this is not working correctly.

2

The inverter power appears to be going negative. There is no such thing as negative power.

3

That appears to be working.

However you may be seeing a lot of accumulated errors because you are using an inappropriate integration method. Try left, instead of the default trapezoidal.

4

In this case, negative values indicate power going into the battery (ie, it is being charged). I have separate template sensors that splits it into two different sensors for the Energy dashboard.

5

Thanks. I’ll give that a try.