FoxESS Community - Owners & Installers Forum

I've just had a new battery system installed onto an existing solar panel installation. Before the battery install, my base load was 0W most of the time.

Since the battery install, the baseload is, on average, 23W and I can see from my smart meter IHD that the system is constantly pulling a small amount from the grid, even when the batteries have power and the sun is shining.

I would expect nothing to be pulled from the grid if battery/solar power is available. I understand that sometimes power will come from the grid when the battery is lagging if something like the oven is turned on, but that this would go back to zero once the batteries were supplying the power.

Is this normal behaviour? It adds up to about 0.5kwh per day which, although small, is more than I would expect.

It is normal behaviour (particularly at this time of the year), the system sets a bias point which is usually from the grid when in Self Use and there is not enough PV to change the bias to export. (it's needed to meet the regulations for isolation from the grid for solar battery systems)

There is a grid compensation setting (available to the installer only), this allows you to change the bias point so that it doesn't use as much grid power, instead it uses the battery power to set the bias towards the grid - the actual setting depends on each individual system, if you are showing a steady 20-30 watts draw when there isn't sufficient solar to export then you could ask your installer to set a bias of say -40 watts, which should reduce your grid usage to near zero.

Thanks, I will ask them. It seems to draw the power from the grid even if I am generating 3kw+ solar which isn't being used by anything in the house.