Unrequested Export to Grid

[chutuk]

Hi,

Had my system installed for a week and have been pretty pleased so far. I've got a 3.6kw H series inverter, 1x ECS 2900 Master with 2 slaves and a Zappi car charger which is controlled by Octopus intelligent go.

During the day, all has been fine, solar is firstly powering the house, then charging the battery then any remaining is being exported to the grid. Happy days. However during the past two nights, the Zappi car charger has randomly started charging the car while in Eco+ mode without any instruction from myself or Octopus. This is draining the battery and also pulling in power from the grid at peak times, potentially costing me a lot of money. The only time it 'should' do this is if there is excess generation from PV and the battery is at 100%. However both times the battery has been <100% and it's been at night, so no solar.

Looking at the Fox app, it appears this is due to random short exports to the grid which shouldn't be happening. Luckily I was able to catch this on the below animation. You will see from the direction of the flow, it shows I am exporting 12w to the grid, before refreshing and correcting itself to show an import of 9w. However, this incorrect reading is enough to make the Zappi kick in and begin car charging, despite there being no excess.

Can anyone please explain why the system may very briefly think it is exporting to the grid? There are no advanced settings configured in the Fox app, certainly no force discharge settings. The only setting configured is to force charge the battery to 65% between 03:00 and 05:30.

[Dave Foster]

When a large load turns on or off the sudden demand will in the case of a new load be initially drawn from the grid and very quickly replaced by the batteries balancing the load, likewise when something turns on you get a short period where the batteries are providing power but no load exists and so the grid will show export - these are called artefacts as they only last for fractions of a second but if the 5 minute data sample is taken when it happens it looks like you are importing or exporting for 5 minutes until the next data sample occurs.

Likewise devices such as the Zappi that look for export to enable charge sometimes see this small amount and switch to charge before realising (usually 30 seconds later) that there is no export and so they switch off again.

The Zappi has a setting called Export Margin that can be set to avoid this behavior - I set mine to 150 watts and then it will not start unless it sees more than 150 watts of surplus.There is information in how to change this in settings here https://support.myenergi.com/hc/en-gb/a ... rted-power and here how to change it https://support.myenergi.com/hc/en-gb/a ... d-Draining - click the 'standard settings' link

[chutuk]

Thanks so much for your detailed response. I will check that setting out