Battery Monitoring

Emoncms
1

Hi,

I have a feed from my home battery that provides a kW reading every 5 minutes.

How do I get this into the form of a kWh accumulator so that I can compare directly with my Octopus data?

I’ve tried a number of things but am not getting the numbers to align. Any input much appreciated.

Thanks,

Chris

2

Hello @abbbbbottttt

I assume that you are getting a number of different metrics from the home battery including:

  • Grid import / export power readings in kW, hopefully to multiple decimal places?
  • Battery discharge/charge power in kW?
  • Solar generation if applicable in kW?

Is that correct?

You will want to take the grid import/export reading, assuming it’s positive when importing and negative when exporting I would:

  • Apply “allow positive” input process
  • Multiply by 1000 to convert to Watts
  • Use “power to kWh” input processor to create a cumulative kWh feed.
  • Use “power to kWh / custom minutes” to create a direct comparison half hourly kWh feed
1 Like
3

Thank you.

What does “power to kWh / custom minutes” do? How is it different to “power to kWh”?

I feel liek I’m missing some fundamental bit of understanding here.

Thanks,

Chris

4

‘power to kWh’ integrates power continuously it results in a total kWh reading a bit like what you see on the front of your electric meter.

‘power to kWh / custom minutes’ integrates the power within the custom set interval only and so you get total kWh in that half hour which is the format that octopus supply data as.

It is also possible to convert the first method to half hourly values after the fact using delta mode, see: Calculating Daily kWh — OpenEnergyMonitor 0.0.1 documentation

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