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How many powerwalls per inverter?

Discussion in 'Tesla Energy' started by masam, Apr 22, 2016.

  1. masam

    masam Member

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    I know that currently the StorEdge inverter can be used to charge a single PowerWall. I haven't had much luck getting concrete answers to hooking up multiple PowerWalls to a single inverter. Does anyone here know whether/how/if it's possible to use multiple PowerWalls with a single StorEdge ?
    On a related note - are there other inverters that can be used for this ? So far my solar installer doesn't have other solutions.
    Thanks !
     
  2. Utahken

    Utahken Member

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    Currently one inverter per one powerwall. Later this year solaredge hopes to release a software update only to allow 2 powerwalls per one inverter. The current draw stays the same, but the capacity is doubled.
     
  3. Ampster

    Ampster Member

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    Wow, that is a big limitation. I thought the whole idea behind the self contained DC to DC converter was so you could parallel them on the DC buss.
     
  4. masam

    masam Member

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    Yeah, that's the one thing holding me back. The lack of information from Tesla and the fact that only one inverter seems to (currently) support the PowerWall makes it a significantly less attractive option. I don't want a bank of ugly batteries sitting in my basement. A generator almost seems worth it
     
  5. ecarfan

    ecarfan Well-Known Member

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    According to my contact at Tesla Energy, the only Powerwall compatible inverter in the US at this time is the SolarEdge SE7600A-USS model. I don't know anything about a "StorEdge" inverter.

    I am only getting one Powerwall so have not asked if that inverter can be connected to multiple Powerwalls.
     
  6. Ampster

    Ampster Member

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    The Powerwall was designed to be a showcase on your garage wall for all your neighbors to see that you have a Tesla in your garage. LOL Even with Lithium ion batteries we are not talking bulky and corrosive lead acid batteries. Every time I look at my Lithium Ion batteries I think of the money I am saving and how I will have power during a blackout.
     
  7. masam

    masam Member

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    Ampster- can you share some details on your setup? The only options I've been given so far are lead acid batteries for backup power. Thanks!
     
  8. Ampster

    Ampster Member

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    I found some used 180Ahr Lithium Ion batteries in a classified section of diyelectriccar.com . They cost $100 per kWhr. I have 48 of them and wired them in groups of 3 parallel for a pack of 3P16S (24kWhr) . Because they are nominally 3 volts that gets me to 48 volts which is what my Outback Inverter runs at. I had the ability to test some of them randomly before I invested in all 48 and my bet paid off. Normally new Lithium Ion batteries are about $400/kWhr but you can find used Tesla modules for $250 and Volt and Leaf cells for $200. Long term they are much cheaper and less maintenance than lead acid. I don't want to divert this thread any further but feel free to PM me for my email and contract info.
     
  9. Utahken

    Utahken Member

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    The StorEdge inverter is just the SolarEdge inverter with a new DC disconnect that is compatible with the Powerwall. The retrofit kits that contain this new DCD will supposedly not be available until later in 2016.
     
  10. electracity

    electracity Active Member

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    I doubt this is true. There has to be a charge controller, and I doubt it is in the powerwall.
     
  11. miimura

    miimura Active Member

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    That depends on your definition of "Charge Controller". The PowerWall contains a DC/DC converter which can charge or discharge the batteries on command. My understanding is that the firmware in the inverter is giving the commands to the PowerWall for when to and how much to charge and discharge. By my definition, that makes the inverter firmware the "charge controller". The solar MPPT function that is normally done in an off-grid charge controller is actually done by the inverter in concert with the SolarEdge optimizers.
     
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  12. electracity

    electracity Active Member

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    If Tesla's car battery is wired at 300v, so is the powerwall. How it is wired should be shown by the people who disassembled tesla batteries from wrecks. I would be surprised if there is a DC/DC inverter in the powerwall, considering solaredge requires power optimizers to use their inverter with the Powerwall.
     
  13. Ampster

    Ampster Member

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    DC to DC converter in the Powerwall.
    Inverter in the SolarEdge
    That would make your statement correct but I think you misunderstood what Mimura said.
     
  14. Utahken

    Utahken Member

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    Inside the solaredge's DC disconnect is the disconnect, of course, and some relays for switching critical loads, grid and autotransformer. Also included is a possible RGM if that option is selected. There is connection to the powerwall and powerwall's fan too. The solaredge's installation manual shows those things.
     

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