Solar PV vs Grid usage

[Neil1976]

I had solar panels and a 9.5kWh battery installed and switched to Octopus agile tariff but my Givergy cloud shows different usage to the Octopus app. Yesterday Givergy says I imported nothing from the grid but Octopus is showing 9kWh, any reason for the difference? I’ve have the solar/battery setting at eco which was recommended by Givergy support and time battery charge and export are disabled at the moment but will enable export once I have my agile outgoing tariff set up. The battery photo attached was taken before it was commissioned, they installed but didn’t have a Wi-Fi dongle when they installed last week and was only connected on Wednesday.

 

[johnb2713]

The app is saying 0 from grid to home, there isnt a display of grid to battery.

 

[Neil1976]

Thanks for the reply, the grid to battery was also 0

 

[johnb2713]

In all honesty, I dont think Octopus and their metering will be wrong, it's kind of logical that 9kWh could be sunk into charging the battery.

 

[Neil1976]

Something isn’t correct, my average consumption is 8-9kWh, the solar and battery (according to the Givergy app) supplied 9kWh so that would appear my usage has doubled since solar installed.

 

[Andy1733]

Something isn’t correct, my average consumption is 8-9kWh, the solar and battery (according to the Givergy app) supplied 9kWh so that would appear my usage has doubled since solar installed.

Is the inverter set to charge from grid?
I'm a bit confused as are you say 9kw is double your usage?

 

[Neil1976]

I can’t see a setting for charge from grid, I have eco mode enabled that states it will dynamically charge and discharge your batteries to minimise your import from the grid. I have timed charge, timed discharge and timed export disabled as advised by the installers.

 

[Andy1733]

Do you have the octopus image showing 9kwh usage

 

[Neil1976]

I’ve added the last 3 weeks from the Octopus app. Last Wednesday (20kWh) and Thursday (13kWh) are high as timed discharge was enabled but this was disabled on Thursday afternoon by GivEnergy support who advised it should be fixed but Friday and Saturday are still showing similar usage to before the installation.

 

[Andy1733]

The only thing I can think of is your battery's are being charged from the grid and then discharging through the day/evening. If octopus metre is saying you are using this amount then you need to check the settings or ask the fitter to check them. How many solar panels do you have. As a comparison I have 4kwh of panels and this month the most I've generated was 3.2kwh in a day.
Which wouldn't be even close enough to change my 9.6kwh worth of battery's.

 

[Neil1976]

I have 10xJA Solar 385W panels so it definitely doesn’t sound correct with your comparison. If I look at Friday the GivEnergy app is giving some odd figures, see photo attached while still saying I took nothing from the grid. I’ll give the installation guys a call tomorrow.

 

[Neil1976]

Just an update on my issues, Octopus and Givenergy are standing by the figures they are reporting as accurate however Givenergy have advised it could be linked to the position of CT clamps done at installation and have asked for the following but I really don’t know what I’m looking for

- if you have a smart meter, if you do, where is the CT clamp placed?
- where the EM115 CT clamp is placed
- has the CT cable been shortened or extended

Any advice would be grateful

 

[johnb2713]

Just an update on my issues, Octopus and Givenergy are standing by the figures they are reporting as accurate however Givenergy have advised it could be linked to the position of CT clamps done at installation and have asked for the following but I really don’t know what I’m looking for

- if you have a smart meter, if you do, where is the CT clamp placed?
- where the EM115 CT clamp is placed
- has the CT cable been shortened or extended

Any advice would be grateful

The lower CT clamp looks like it's had it's cable extended, obviously we cant tell what it's function is in your installation. I dont see how the CT clamp could cause the issues youre experiencing.

 

[Neil1976]

It looks like the lower one is connected to the car charger I had installed. I’ve asked the installer Box Energy to investigate and hopefully fix the issue.

 

[Andy1733]

Is the top CT clamp pointing in the right direction can't see from images.
Also if a electrician can confirm. If the meter is reversed wired would this still work but give false readings?

Another option, again a electrician can confirm if this will work. Try the clamp on the neutral but point the arrow away from the cu, towards the main metre

 

[Neil1976]

The top clamp doesn’t seem to have any arrow in it so can’t tell if it’s the right way or not

 

[Andy1733]

The top clamp doesn’t seem to have any arrow in it so can’t tell if it’s the right way or not

Have you reversed it an tried it?

 

[johnb2713]

Have you reversed it an tried it?

As stated earlier, be careful reversing the clamp, it can cause the inverter to go to full output voltage in the case of my Growatt inverter thats 265.5v.

 

[Andy1733]

This is how I understand a CT
Clamp works. I'm sure of I'm wrong someone will be along correct me..
The CT clamp works by reading the current flowing in the direction the arrow is facing. So if the CT clamp is pointing towards the meter and you have the back to grid feed turned off/disabled. You will get the zero figure like you stated in the op.
If the arrow on the CT clamp is facing towards the CU and you have used 9kwh of power like octopus have stated, then you should get 9kwh readings from the CT clamp.
I read somewhere when I was installing mine that if the live and neutral feed to the meter are reversed (by mistake) this can give the meter a wrong reading.

 

[Andy1733]

As stated earlier, be careful reversing the clamp, it can cause the inverter to go to full output voltage in the case of my Growatt inverter thats 265.5v.

Sorry I didn't see this john