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Poorly researched Motley Fool article bashes Powerwall

Discussion in 'Tesla Energy' started by googlepeakoil, Sep 29, 2016.

  1. googlepeakoil

    googlepeakoil Member

    Joined:
    Mar 6, 2015
    Messages:
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    Location:
    England
    Motley Fool (which admits it owns shares of Tesla) and normally talks up Tesla (their cars, the Gigafactory, the game-changing aspect of the business, self-driving) has done a error strewn and pretty negative piece on the Powerwall accusing Musk of false claims about the Powerwall's cycle life - that it's a worse chemistry than others.
    1. Error - They also call the discontinued 10kw Powerwall a Powerpack - a name used exclusively for the wardrobe sized 100kW Powerpack.
    2. The author is quoting industry standard lithium chemistry figures of "80% after 500 cycles" while claiming it to be Panasonic's OWN data!
    This presentation here shows 3000 cycles and about 90% charge - and the title "Development of High power and Long life Lithium secondary batteries" gives away the fact they've got the chemistry doing longer than industry standard cycles (ie. a phone/tablet/mp3 player that might be obsolete in 2-3 years).
    by Panasoinc.
    The article is "Development of High power and Long life Lithium secondary batteries"
    Shoichiro Watanabe, Takashi Hosokawa, Ken’ichi Morigaki, Kensuke Nakura and Munehisa Ikoma
    http://ma.ecsdl.org/content/MA2011-02/17/1282.full.pdf
    This also goes against real-world use (one famous Norway blogger calculated 3% loss of range after 100k miles). It also goes against the fact that the car batteries / and probably the Powerwall - don't 100% cycle all the time. Users have to click through a screen to do a "100%" range charge - and 100% and 0 miles is probably not "0-100% of the actual battery as people report circa 75kw available on an "85" car) - so 0 miles and 100% are probably 6% and 98%.
    3. The article also keeps quoting the word thermodynamics for explaining why the cycle life won't achieve 10 years of cycling (365x10=3650 cycles) - when that has nothing to do with it - it's to do with chemical bonds in the battery and ability to hold charge - nothing to do with thermodynamics!
    Would like to see other people's opinion. Anyway, here's the article.
    "Don't Believe Elon Musk on the Powerwall"
    Don't Believe Elon Musk on the Powerwall -- The Motley Fool

    Note - it is correct the 10kw Powerwall model (which Tesla advertised as good for 500 cycle use - emergency power situations) was discontinued. There are cheaper more powerful products on the market that do the same thing.
     
  2. googlepeakoil

    googlepeakoil Member

    Joined:
    Mar 6, 2015
    Messages:
    225
    Location:
    England

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