Energy Products

where does it go

When my system makes more kWh of electricity than I use this excess power goes back into the grid. If there is a power outage my system shuts down so that it will not put power back into the grid that could potentially hurt utility workers working on the lines to fix the outage. - this makes complete since to me.

Okay now if I get a few powerwalls added to my system if I understand correctly instead of shutting down in a power outage the system will disconnect from the grid and during the day the panels will keep producing power to run the house and to keep the powerwalls charged and at night the house will run off the powerwalls

okay, so now one question. during the day if the power goes out and the system disconnects from the grid if the panels are producing more power than the house is using and the powerwalls are fully charged where toes the extra power that the panels are generating go? -


  • edited August 2019
    if the grid goes down the panels will shut down unless you have battery backup, your home will run on the batteries same as having a generator, as the batteries get used the panels will continue to recharge. If the batteries are full then there is no where for the power to go, so the panels will shut down until needed again or the power is restored.
  • so when the power is down the house runs primarily off the batteries and the panels only turn on enough to keep the batteries charged - - so there is no over production - correct?
  • thank you
  • edited November -1
    Technically however, there's no way to shut solar panels down. The panels continue to be exposed to the sun and producing the excess heat which your inverter would convert to electricity. So in the scenario above, your inverter disconnects from the panel array.
  • edited August 2019
    ...and the PV array goes to it's maximum open-circuit Voltage at zero Amps. If you watch its behavior on the Tesla app, you'll see the TEG switching the PV off until some energy is depleted from the PWs, then switch the PV back in to charge the PW back up. Rinse and repeat. I have no idea how far down the PW is allowed to go before the TEG switches the PV in again.
  • thank you for all of the replies.
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