I don’t. When I installed my solar panels and batteries there was a stipulation that if I charge my batteries from the grid, I don’t get a tax rebate. Essentially they gave me $10,600 USD for me to not do that. If they catch me doing it, I would need to pay that back. However there is an exception for inclement weather. If there is a severe thunderstorm, fire, etc. in my area, my batteries are automatically charged from the grid.