I've just had a Powerwall and solar installed, and am trying to come up with the optimal way to balance home backup needs with charging my Tesla Model 3. I could use some feedback. Here are the details:
-- Solar 5.7kWp system
-- Single Powerwall unit, presently set to provide 50% backup power, 50% self-power
-- Utility uses Net Metering, rates do not depend on time of use ( typical rate for electricity in the Duke Energy region is presently 0.71 cents per kWh)
-- Household usage (other than charging the car) avg/day 20.29 kWh
-- Typically charge the car from 60% to 85%, twice a week (I work from home and don't put a lot of miles on it)
Right now, I've got my car set to start charging its battery every day at 11 am, about the time the solar unit begins to near peak output. The car draws from solar and from the battery until the battery goes down to 50%, then from solar and from the grid. Car charging ends about 2:00pm, and after that the solar recharges the Powerwall, sending excess to the grid to be banked. After the sun goes down, the Powerwall again begins discharging, but at a much slower rate than when the car is charging.
Does this make sense? Would it be wiser just to let the car charge from the grid at night, and keep the Powerwall on 100% charge and 100% backup? Some other arrangement? Ideas welcome.
-- Solar 5.7kWp system
-- Single Powerwall unit, presently set to provide 50% backup power, 50% self-power
-- Utility uses Net Metering, rates do not depend on time of use ( typical rate for electricity in the Duke Energy region is presently 0.71 cents per kWh)
-- Household usage (other than charging the car) avg/day 20.29 kWh
-- Typically charge the car from 60% to 85%, twice a week (I work from home and don't put a lot of miles on it)
Right now, I've got my car set to start charging its battery every day at 11 am, about the time the solar unit begins to near peak output. The car draws from solar and from the battery until the battery goes down to 50%, then from solar and from the grid. Car charging ends about 2:00pm, and after that the solar recharges the Powerwall, sending excess to the grid to be banked. After the sun goes down, the Powerwall again begins discharging, but at a much slower rate than when the car is charging.
Does this make sense? Would it be wiser just to let the car charge from the grid at night, and keep the Powerwall on 100% charge and 100% backup? Some other arrangement? Ideas welcome.
