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Powerwall 2 not charging completely before sending power to grid

Looking at the Powerwall app, from 0 to 100% charge - input is now only 11.3kw. Used to be higher at 13.5kw. The Powerwall is only 18 months old.

Are the batteries starting to fail already?


  • Depending where you live, and the environment where the PWs are placed, it's possible that some of the energy loss you're seeing is going towards managing the temperature of the batteries. There's actually a "coolant" loop and radiators built into the things, and the environmental management function tries to keep them within a specific temperature range. It's been an unusually cold Winter in many parts of the USA (World?)

    Even during the best of times, a PW consume about 250Wh per day, just in self-management.

    In addition to that, there's a ~10% round-trip energy loss due to Thermodynamics Laws (you can't fool Physics!). 90% efficient is about all you can expect out of them.

    I'd let your PWs warm up for a week or so of higher temps within the operating range, and do another discharge-charge check to see if you get improved results. You can check the environmental specs from the PW spec sheet:

    ...and here's the Tesla Customer Support numbers:

    1-877-961-7652 (Found to work as of 10/30/20)

    Good luck!
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