Energy Products

Charging the Powerwall from solar but with no CT clamp

I have a customer with a 50kWp PV system, 30kW on one barn roof, and 20kW on another barn roof. The main incoming power supply is on another building across the yard from the 20kW, and 70m from the 30kW. Each PV system is connected into each barn, with its own meter.

My customer would like 2 or 3 Powerwalls, but they would need to be located near the meter and there is no way to get a CT clamp on to either solar system without digging up 70+ metres of concrete.

Can the Powerwalls be set to charge just by reading the CT clamp at the main incoming head, with no solar reading? I spoke with someone at Tesla and they said no but i can't see why monitoring the solar is important to charging the batteries, as the amount of solar generated is only relevant to monitoring the solar, it doesn't determine when a battery will charge or not, that is only determined by measuring how much power is being exported back to the grid. My understanding was that the Tesla monitored what went to and from the grid to determine whether to charge, not look at what the grid was importing and look at what the solar was generating and net off the difference?

Comments

  • You may need to go with a distributed system, with TEGs and PWs at each barn location, treating each as an independent installation.

    Sounds expensive, too.
  • > @smallyeti said:
    > I have a customer with a 50kWp PV system, 30kW on one barn roof, and 20kW on another barn roof. The main incoming power supply is on another building across the yard from the 20kW, and 70m from the 30kW. Each PV system is connected into each barn, with its own meter.
    >
    > My customer would like 2 or 3 Powerwalls, but they would need to be located near the meter and there is no way to get a CT clamp on to either solar system without digging up 70+ metres of concrete.
    >
    > Can the Powerwalls be set to charge just by reading the CT clamp at the main incoming head, with no solar reading? I spoke with someone at Tesla and they said no but i can't see why monitoring the solar is important to charging the batteries, as the amount of solar generated is only relevant to monitoring the solar, it doesn't determine when a battery will charge or not, that is only determined by measuring how much power is being exported back to the grid. My understanding was that the Tesla monitored what went to and from the grid to determine whether to charge, not look at what the grid was importing and look at what the solar was generating and net off the difference?

    I believe that they monitor the solar generation to decide how much they can charge the powerwalls, as they are only supposed to charge the powerwalls from solar when there is a solar system. Also, they do have a remote monitor system available to monitor the solar. https://www.tesla.com/support/energy/more/installers/installing-powerwall
    has some details about that. Not sure if it will go 70m though.
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