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Question: difference in to/from Powerwall stats

Discussion in 'Tesla Energy' started by rjdunn, Jul 14, 2018.

  1. rjdunn

    rjdunn Member

    Joined:
    Jul 7, 2018
    Messages:
    24
    Location:
    Emerald Isle, NC
    I’ve had my Powerwall running just over a week now, and I’ve noticed that each day, the amount to the Powerwall is higher than the amount from the Powerwall. Maybe a half kW or so, sometimes a bit moreif I store/retrieve more power. Is this:

    • AC-DC-AC round trip loss
    • Power used by the Powerwall itself
    • Something else?
    Thx in advance for the insights of the hive mind ;-)

    The Powerwall seems to be working perfectly, as expected...

    -Joel
     
  2. rjdunn

    rjdunn Member

    Joined:
    Jul 7, 2018
    Messages:
    24
    Location:
    Emerald Isle, NC
    The more I think about it, I believe I’m just noting the 89% rated round trip efficiency, though the numbers work more like 80% on weekly basis for this first week...what are others seeing?
     
  3. cwied

    cwied Member

    Joined:
    Jan 13, 2015
    Messages:
    390
    Location:
    San Mateo, CA
    The powerwalls lose energy over time too. I don't know if that's real leakage or just rounding errors due to the small in- and outflows as they try to maintain a 0 energy flow. The loss seems to work out to about 1% per day. You can see this if you switch to backup-only for a day or two.
     
  4. ewoodrick

    ewoodrick Active Member

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    Apr 13, 2018
    Messages:
    1,069
    Location:
    Buford, GA
    Batteries are not 100% efficient.
    Inverters are not 100% efficient

    Do you feel any heat anywhere on the Powerwall?
    That's your efficiency
     
  5. Siggy101

    Siggy101 Member

    Joined:
    Jun 29, 2017
    Messages:
    110
    Location:
    Geneva, Switzerland
    Where is your Powerwall situated? Is it outside in full sun or a cold place? If so, it could be the heating/cooling system.
    Otherwise, I would imagine what you are seeing is just the normal losses from AC/DC conversion, component losses etc.
     
  6. rjdunn

    rjdunn Member

    Joined:
    Jul 7, 2018
    Messages:
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    Location:
    Emerald Isle, NC
    It’s in a shaded place, mild coastal climate. Yep, I think it’s just normal, but being a newbie, I’m trying to get a baseline normal ;-)

    Thx!

    -Joel
     
  7. Siggy101

    Siggy101 Member

    Joined:
    Jun 29, 2017
    Messages:
    110
    Location:
    Geneva, Switzerland
    Yep, it sounds like that's about normal then.
    Congrats on the nice new Powerwall. I hope it serves you well for many years to come!
     

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