energy consumption grid purchase figures

[Iggsy469]

The figures for grid purchase on my Fox Cloud app 2.0 are consistently lower than those shown on my energy suppliers app and my smart meter. Anyone else had this or explain why. Thanks

[Dave Foster]

Which inverter model do you have ?, and can you provide some examples of the differences please

[Iggsy469]

We have a H1/AC1 inverter

grid consumption per supplier Nov 201.62 Dec 304.8 Jan 193.74
grid consumption per supplier Nov 189.3 Dec 288.3 Jan 180.2

the daily difference in Jan is an average of .5 Kw/h

[Dave Foster]

We have a H1/AC1 inverter

grid consumption per supplier Nov 201.62 Dec 304.8 Jan 193.74
grid consumption per supplier Nov 189.3 Dec 288.3 Jan 180.2

the daily difference in Jan is an average of .5 Kw/h

Ok, thanks - the inverter uses a CT clamp to measure loads and usage, the CT clamp is typically between 2% - 5% accurate being worse at low loads, it isn't a replacement for the smart meter which can also take power factor into account - the readings from Fox will not be as accurate as your smart meter.

Looking at your usage your daily use is ~6kW (a base load of 262 watt/hours) which is low - you may be able to improve the accuracy by re-positioning the CT clamp away from any other magnetic sources or other CT clamps and/or shortening the length of cable between the clamp and the inverter but you are still within the 5% tolerance.
Optionally you can replace the CT clamp with a meter (Chint or Eastron), they are more difficult to install but are more accurate albeit nothing will be as accurate as the smart meter.