Energy Products

Gateway with generator support

I would like to see a PowerWall Gateway that can handle:
* power whole house (3 or 4 PWs in my case)
* grid-tied solar with net metering
* recharge PowerWall from either source: solar or standby generator
The reason for needing the generator capability is simple: In an extended multiple-day grid outage, my solar can't fully recharge the PWs because here in WA in the winter we only get 8 hours of daylight (and it's cloudy!). A generator, which I already have, would allow me to have power indefinitely, as long as I can get a propane talk fill-up every so often during the outage.

Comments

  • I'm betting this doesn't happen. You can install a transfer switch in the mean time.
  • a generator isn't considered green power. if tesla allowed a generator to charge their powerwalls they would not be eligible for the fed tax credits.

    a 2nd transfer switch can solve your needs. 1st xfer switch(telsa gateway) switches between utility & solar/battery & feeds the 2nd xfer switch which switches between utility/solar/battery & generator.
  • Numerous discussions on this topic. Can’t connect a PowerWall to a standby generator. You might want to have a set of essentials on a separate sub panel for the standby generator but you can’t charge a power wall with a standby generator.
  • Thanks, Passion2Fly, but I'm aware that the current version of PW doesn't allow generator input, which is why I wrote "I would like to see ...".
    > @Passion2Fly said:
    > Numerous discussions on this topic. Can’t connect a PowerWall to a standby generator. You might want to have a set of essentials on a separate sub panel for the standby generator but you can’t charge a power wall with a standby generator.
  • There is probably a way you can wire the generator switch between the solar and the gateway to fool the gateway into thinking it is coming from solar
  • I wouldn't...
  • Neither would I. You would be combining two very stable power sources (Solar PW) with an unstable one (generator) and would lack any way to shed excess energy once the powerwalls are full. Expect damage to equipment inside the home and / or to the TEG.
    Simply choose between solar + PowerWalls or generator.
  • No, you cannot charge a PW from a generator, no matter how you wire it. The solution in Jakespeed's post above it good. All that's required is another large switch with the amp rating of your whole house, and a breaker to send/cut the grid power to a direct feed in the gateway. This way you can use either the gen if there's no sun or grid, or use the grid to run the house and charge the PW at the same time. Ours is setup this way and we have total flexibility...we're never without power. If we see the PW charge getting low at sundown, we switch over to the grid, let the PW charge from the grid and pray for sun the next day. It's hard to live off the sun if there isn't any. But since we're in the tropics, there's usually enough sun to run 99% of the time off the sun.
  • 1. Thanks for the heads-up on the investment tax credit (ITC).
    That led me to look at https://www.energysage.com/solar/solar-energy-storage/energy-storage-tax-credits-incentives/
    "If you are installing energy storage on a residential property, it is eligible for a credit under the ITC – as long as the battery is only charged by an on-site renewable energy system like solar."
    That's a better explanation than the statement on Tesla's website.

    2. I think I understand your solution re two xfer switches. A little complicated, but possible. Thanks.

    > @jakespeed said:
    > a generator isn't considered green power. if tesla allowed a generator to charge their powerwalls they would not be eligible for the fed tax credits.
    >
    > a 2nd transfer switch can solve your needs. 1st xfer switch(telsa gateway) switches between utility & solar/battery & feeds the 2nd xfer switch which switches between utility/solar/battery & generator.
  • Do note that the charge-from-the-grid option isn't available in the vast majority of the continental US. You'd need to check with your utility, and/or the requirements for the tax credits and other incentives. Often, claiming incentives precludes the grid-charge option.
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