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Powerwall 2: Technical

Discussion in 'Tesla Energy' started by Aussie, Mar 4, 2017.

  1. Aussie

    Aussie Member

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    The main reason why they recommend the AC Powerwall is because Tesla will not offer the DC Powerwall at all anymore. Only AC version will be available.
     
  2. JeffreyY

    JeffreyY Member

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    True. In the US, supposedly DC Is still available, but I believe even that will disappear soon
     
  3. electracity

    electracity Active Member

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    Why do you think the DC version will disappear?
     
  4. MP3Mike

    MP3Mike Active Member

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    Or maybe they can hook the new generation of Wall Chargers up to the Powerwall system via the multi-WC interface to control how much power can be used at any given time.
     
    • Like x 1
  5. Ulmo

    Ulmo Active Member

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    I assumed they would already have this working years ago. I don't know why they don't now.
     
  6. doubleohwhat

    doubleohwhat Supporting Member

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    I think it's going to depend on what the "Energy Gateway" AKA Backup Gateway is capable of. That seems to be the brains of the powerwall 2. A specs sheet for that thing would be awesome.
     
  7. Ulmo

    Ulmo Active Member

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    It might only be proper switching equipment, and the brains are inside the PowerWall 2.
     
  8. doubleohwhat

    doubleohwhat Supporting Member

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    The attached document is what makes me think the gateway is the brain.

    The document indicates the transfer switch is an optional add-on to the gateway.
     

    Attached Files:

  9. jeep1979

    jeep1979 Member

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    Here is a copy of the typical configurations with the gateway for full and partial backups

    Tesla.jpg
     
    • Informative x 5
  10. doubleohwhat

    doubleohwhat Supporting Member

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    Thanks for that. That answers several of my questions.

    Do you happen to know if the solar inverter make/model matters or will any inverter work just fine with the AC powerwalls?
     
  11. ohmman

    ohmman Maximum Plaid Member

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    I'm guessing here, but based on that diagram, it doesn't seem like it's reliant upon the inverter. Since they both hang off of the main panel, they both provide/draw AC to the panel. And the Energy Gateway is between the panel and main service. My guess is that the Powerwalls are agnostic to the source of AC power - that is, they don't know if they're getting it from the inverter or the utility.
     
  12. jeep1979

    jeep1979 Member

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    I agree, it looks like what kind of inverters used do not matter.

    I received my proposal contract yesterday and after Tesla makes a couple of minor changes I will sign and send in. The contract says installation will occur 30 - 90 days after signing, but talking to the Tesla rep, he says that things are ramping up very quickly and that installation could begin before the 30 day minimum.

    I am going with two batteries and a whole house backup. My main panel requires an upgrade for the system. Tesla is charging $1,750 for this which, according to my electrician, is a good price for the upgrade.
     
  13. JeffreyY

    JeffreyY Member

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    That is correct. In my discussions with the Tesla rep who came to my home, the Gateway changes the frequency of the power to either mimic the grid being up or down. The PowerWalls only respond to the gateway "souring the milk" as it were.
     
    • Like x 1
  14. Zythryn

    Zythryn MS 70D, MX 90D

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    The PowerWall will last a much longer time if it is only powering part of the house.
    You also need to keep in mind the 7.5kW limit.
    I am sure there is some protection built in, but why cause surges over that?
     
  15. liuping

    liuping Active Member

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    I think with 2 powerwalls the household limit would be 15kW peak, and 10kW continuous. That should be enough for the most houses (with the exception of EV charging, electric ovens and AC, which could be staged or only run during the day during peak solar output).

    I'd rather have the option to run anything in the house during long power outages, even if I cannot run them all at the same time.

    Also, I might add more powerwalls later, maybe even going off grid altogether.
     
    • Informative x 1
  16. Zythryn

    Zythryn MS 70D, MX 90D

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    I have been told, by my future installer, that multiple Powerwalls only increase the total power and not the load ratings.

    I envy your climate in San Diego. It would take a whole lot of Powerwalls for us to go off grid here in MN.
     
  17. MP3Mike

    MP3Mike Active Member

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    Was this with talking about AC or DC Powerwalls? For DC that makes sense as the load capacity would be determined by your existing inverter. For AC it does not since each unit has its own inverter. (And if you couldn't increase the load capacity by adding more Powerwalls you could never do a whole house system.)
     
  18. abasile

    abasile Working on EVBuySell

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    My PV system uses micro-inverters which nominally output 240V, so I'd be going with an AC PowerWall.

    Apart from possibly EV charging, all of our backed up loads would be at 120V. I admit that I'm not sure how this works - perhaps micro-inverters and the AC PowerWall connect to the neutral. For the EVs, it seems that it would be most convenient to install a 20A 120V outlet in the driveway by our EVSE, as this could have other, non-backup uses such as running a vacuum cleaner, an electric snowblower, etc.

    I'm corresponding with Pick My Solar (Compare Solar Companies | Solar Marketplace | Pick My Solar) regarding California's SGIP and installing a PowerWall, as they're the company that collected bids for our recent PV install and they were the first to tip me off regarding SGIP (before I started reading this thread). But they're now waiting on the state to provide more details as to the SGIP application process.

    By the way, I originally tried going with SolarCity for PV, but after wasting several weeks, they eventually "disqualified" us because we have a lot of shading. SolarCity seemed to not grasp the fact that we were paying cash and would thus be in a position to tolerate lower production and a longer system payback time. So our money went elsewhere, and we ended up with better, more efficient panels. After that odd experience, SolarCity is not my default choice to install a PowerWall 2. Hopefully Tesla will shake things up for the better!
     
  19. SolarFrank

    SolarFrank Member

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    Tesla Power 2 is AC, they discontinue DC Powerwall.
     
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  20. doubleohwhat

    doubleohwhat Supporting Member

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    The DC version was still available as of last week. I'm not sure how much longer that will be the case though.
     
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