We had 12 solar panels and 5kW EP6 plus battery installed in mid Nov. Our 'from grid' readings on Fox app are consistently 20-25% lower than the amount of electricity billed by Octopus. We have just been set up for export and 'to grid' figures on Fox app are also 20-25% lower than what is reported on Octopus app.
Have queried with installer who said that they would contact Fox but haven't got back to us. Have emailed Fox on 18/12/25, received ticket no, dame day but no response yet.
How accurate should the readings on the Fox app be?
As a rule if using a CT clamp to measure power, they are between 2 & 5% accurate (worst is at low loads) - 25% is much further out than I have seen before.
Possibly the installer has clipped the clamp to the wrong cable, extended the CT cable too far, or has used a CT clamp with the wrong ratio.?
Possibly the installer has clipped the clamp to the wrong cable, extended the CT cable too far, or has used a CT clamp with the wrong ratio.?
Thank you. Our load is approx 6-7kWh per day. I'll contact our installer again
If you open up your Fox Cloud 2.0 app, you can swipe right and then down to get your energy graph up (tip, then press top right icon on that panel to make graph bigger) Take a screenshot of this for yesterday/today for example and post these up.
Using these graphs you could make a test, so if you are able to turn off most items in your house down to your base load (think wifi router/heating minimums) Fill a kettle to top and flick it on, once it has boiled, you could then inspect after 5-10 mins the above graph and you should see a 3kW (or close to this) Load Consumed
Using these graphs you could make a test, so if you are able to turn off most items in your house down to your base load (think wifi router/heating minimums) Fill a kettle to top and flick it on, once it has boiled, you could then inspect after 5-10 mins the above graph and you should see a 3kW (or close to this) Load Consumed
Have attached a graph, hope you can see it. Boiled a full kettle at 21.40, load didn't change. Load increased earlier when oven was on between 16.45 and 17.15 and always shows spikes when washing machine and microwave are on.
Attachments:
I would not say your grid CT clamp is backwards, looks like a nice fine graph to me. I am no expert though, so still need to know why your system shows different to energy supplier.
I cannot see if that bottom battery SoC line on your graph is reading 20% or 30%, but you can see it stopped dead in supplying power. Your solar then kicks in, and you can see the battery gains charge after not working at all for a few hours, you can clearly see your oven on, and the battery was supplying energy quite well. There is a spike I see, on right that looks like it was kettle, but no timeline to verify... but looks likely it was.
You may need to go to your Octopus account, go back a day or two as needed and find a full day of reported usage.
Let's say it claims you took 8.7kWh from the grid, then in your Fox app, just above the graph, find the same day as Octopus to show their readings. Add in your export readings from Octopus for the same day also, let's see what everything looks like.
The graph only updates with data every 5 minutes, it’s possible a kettle boil would not show up on the graph if the last data sample was taken just before you started - it’s best to look at statistics (daily totals) for this (or apply a load for at least 6 minutes).
The trace looks correct all the phases are correct so the meter/ct is working ok and facing the correct direction - if there is a 25% difference to your utility provider I still think it may be a CT clamp with the wrong ratio, CT wiring that is excessively long (it is 10 metres standard but 20 metres is an absolute maximum).
Here are some example images to show what I was looking for to check usage. Take pictures of write down values, whatever works best.
Fox Cloud 2.0 App reported usage
Import: 18.50 kWh
Export: 5.30 kWh
Octopus Import: 19.41 kWh (Zappi CT Clamp = 19.5 kWh)
Octopus Export: 5.29 kWh (Zappi CT Clamp = 5.2 kWh)
Someone can check my math's but I think the Fox CT Clamp is reading about 5% under.
Fox Cloud 2.0 App reported usage
Import: 18.50 kWh
Export: 5.30 kWh
Octopus Import: 19.41 kWh (Zappi CT Clamp = 19.5 kWh)
Someone can check my math's but I think the Fox CT Clamp is reading about 5% under.
As I mentioned in my first post, I have checked the from grid and to grid with our Octopus import and export figures. They have been very different every day since installation on 19/11. I am attaching 3/1 and 4/1. I am going to phone my installer
Attachments:
I have made this quick spreadsheet to show the % of Fox vs Octopus
Hopefully your installer can come and check system, as Dave mentioned could be issue with CT clamp cable length or something. As you are a low power user, this could also skew the %, mine is quite close to real use.
Best of luck with your phone call today.
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Best of luck with your phone call today.