TMC is an independent, primarily volunteer organization that relies on ad revenue to cover its operating costs. Please consider whitelisting TMC on your ad blocker and becoming a Supporting Member. For more info: Support TMC
  1. TMC is currently READ ONLY.
    Click here for more info.

The Solar Semi Range Extender

Discussion in 'Semi' started by Haxster, Nov 18, 2017.

  1. Haxster

    Haxster Member

    Joined:
    Apr 4, 2016
    Messages:
    858
    Location:
    Silicon Valley
    While putting solar cells on passenger EVs doesn't make a whole lot of sense, it may be more practical to put them (and maybe some storage) on the trailers that electric Semis pull.

    Think about it:
    Lots of flat surface area
    Typically in the sun a lot
    Appearance is not an issue
    Even when not coupled to an EV tractor, they can help power refrigerated trailers

    Thoughts?
     
  2. Derek Kessler

    Derek Kessler Active Member

    Joined:
    Apr 15, 2016
    Messages:
    1,193
    Location:
    Cincinnati
    Could work for refrigeration trailers, but for charging that utterly massive battery it'd barely make a dent.
     
    • Like x 2
  3. BrokerDon

    BrokerDon Active Member

    Joined:
    Aug 23, 2014
    Messages:
    1,394
    Location:
    Newport Coast, CA
    Hig efficiency / able to purchase separately residential panel Panasonic HIT 330W : 65 inches x 39 inches

    53' semi trailer = 636" = 9.8 residential panels x 2 rows = 20 panels x 330W/panel = 6,600W ~ 6.6kW

    Unfortunately you're going to lose a significant part of that output since panels will need to be mounted FLAT on the roof of the trailer which will dramatically lower their output in winter... or the farther north you travel.

    You also need to factor in:
    • additional wind drag of 20 panels "dirty-ing" up the nice smooth trailer roof
    • panels will add height to the trailer... potentially problematic on lower clearance overpasses & tunnels
    • if Tesla Megacharger electric will be free, adding solar makes zero sense. If not, Tesla electricity would have to be significantly higher than 9¢ per kWh cost of solar (after 30% federal tax credit)
    Cost of panels: 20 x $400 = $8,000
    Racking, charge controller / inverter, installation, wiring = $4,000 ("Wild Ass Guess")
    Total Cost ~ $12,000

    Not sure adding a rooftop of solar to trailers makes sense but LOVE the disruptive thinking!
    [​IMG]
     
    • Informative x 2
    • Like x 1
  4. Haxster

    Haxster Member

    Joined:
    Apr 4, 2016
    Messages:
    858
    Location:
    Silicon Valley
    Let's see:
    15 Watts per square foot (maximum output)
    40 feet trailer length by 8 feet wide
    40 x 8 x 15 ~= 5 kW gross...not too shabby!

    Teslarati estimates the cruising energy at ~2 kW. So, on a sunny summer day in Alaska, a Tesla Semi could run way longer on photons than the driver could legally drive (or hold their bladder).
     
  5. Haxster

    Haxster Member

    Joined:
    Apr 4, 2016
    Messages:
    858
    Location:
    Silicon Valley
    If you like disruptive thinking (like self-driving electric trailers), check out this thread:
    Tesla Semi Battery and Charging configuration
     
  6. BerTX

    BerTX Supporting Member

    Joined:
    May 2, 2014
    Messages:
    3,505
    Location:
    Texas/Washington
    I haven't looked at the numbers myself because it is silly, but something is wrong in theses numbers by at least an order of magnitude. Otherwise the transportation energy problems of the world are solved. Solar trucks for transporting goods. Solar buses for transporting people. Heck, solar trains for that matter.

    I don't like to drive at night, but I guess I'll have to start, just to avoid the traffic from these things. :rolleyes:
     
    • Funny x 1
  7. BerTX

    BerTX Supporting Member

    Joined:
    May 2, 2014
    Messages:
    3,505
    Location:
    Texas/Washington
    There's your hole. If my MS could cruise at 2kW, it could run for 30+ hours without stopping. Does that number seem right to you?
     
    • Informative x 1
    • Like x 1
  8. electracity

    electracity Active Member

    Joined:
    Jun 8, 2015
    Messages:
    4,028
    Location:
    60606
    #8 electracity, Nov 18, 2017
    Last edited: Nov 18, 2017
    2kWh per mile at 60mph? So 60mph needs 4kw.

    no, that's wrong

    Yeah the truck consumes 2 kw at 60mph. But it takes an hour at 2kW to make 2kWh. So at 4 kW from the roof the truck adds 2 mile per hour of sunshine.

    4kW would charge a 1000kWh battery in 250 hours (at 100% efficiency)
     
  9. electracity

    electracity Active Member

    Joined:
    Jun 8, 2015
    Messages:
    4,028
    Location:
    60606
    it can at 15mph

    forget time, calculate distance
     
  10. Haxster

    Haxster Member

    Joined:
    Apr 4, 2016
    Messages:
    858
    Location:
    Silicon Valley
    Uh...yeah. You're right. I misread 2 kWH per mile for 2 kW. Sorry :oops:
    Close-up look at the Tesla Semi "Megacharger" charging port

    So much for perpetual motion.

    Still, it looks like there could be some benefit to using solar panels on the trailer for extending the range (or saving costs) in some situations.
     
    • Like x 1
  11. BerTX

    BerTX Supporting Member

    Joined:
    May 2, 2014
    Messages:
    3,505
    Location:
    Texas/Washington
    Yep, I'm driving at night for sure if all those solar trucks are driving at 15 mph.
     
    • Funny x 2
  12. BerTX

    BerTX Supporting Member

    Joined:
    May 2, 2014
    Messages:
    3,505
    Location:
    Texas/Washington
    Maybe! For sure it may be able to supplement other loads like refrigeration. Working out the extremely variable solar output into power sufficient to add to the driving power might not be worthwhile. Charging while draining batteries is hard. From a cost and efficiency perspective, having the solar stationary and optimized is probably better than carrying it around.
     
  13. electracity

    electracity Active Member

    Joined:
    Jun 8, 2015
    Messages:
    4,028
    Location:
    60606
    #13 electracity, Nov 18, 2017
    Last edited: Nov 18, 2017
    A MW of solar requires about 2 acres and produces about 5MWh per day. If a typical Tesla Semi charges using 800kWh, at 80% efficiency 2 acres of solar will charge 5 trucks per day.

    So a 100 acre solar farm will charge 200-250 Tesla Semis per day.

    Revenue at 7 cents is $5 million/year.
     
  14. Haxster

    Haxster Member

    Joined:
    Apr 4, 2016
    Messages:
    858
    Location:
    Silicon Valley
    Or a really robust phone charger.

    Complicated? I agree. However, Tesla seems to have figured this out for their home PowerWall.

    Of course with the Semi, there would be two charging sources: regen (from multiple motors) and solar...plus maybe a wind turbine that pops up when slowing down quickly.
     
    • Funny x 1
  15. SDRick

    SDRick Active Member

    Joined:
    Jun 25, 2015
    Messages:
    1,432
    Location:
    SD CA United States
    electracity,

    I was hoping someone would do the math on this, thank you. Elon said the semi's would run on sunshine but I am having trouble understanding the logistics and costs. The amount of land required would be inordinate as would the number of batteries to provide charging when photons are low or absent. Will semi trucks running on sunshine pencil at 7 cents?
     
  16. electracity

    electracity Active Member

    Joined:
    Jun 8, 2015
    Messages:
    4,028
    Location:
    60606
    There are already solar plus storage PPAs (Power Purchase agreements) for less than 7 cents, but all the terms are not clear. Even so, I can't imagine the risk/reward of building megacharger power stations is worthwhile for Tesla. So I don't know what Musk is thinking here.

    Putting solar and storage at a Walmart distributuon center to power Tesla Semi seems to make a lot of sense.

    Tesla needs to stay away from commodity businesses. Bulk electricity is a commodity business.
     
  17. Tiger

    Tiger Active Member

    Joined:
    Oct 31, 2016
    Messages:
    1,616
    Location:
    Estonia

Share This Page

  • About Us

    Formed in 2006, Tesla Motors Club (TMC) was the first independent online Tesla community. Today it remains the largest and most dynamic community of Tesla enthusiasts. Learn more.
  • Do you value your experience at TMC? Consider becoming a Supporting Member of Tesla Motors Club. As a thank you for your contribution, you'll get nearly no ads in the Community and Groups sections. Additional perks are available depending on the level of contribution. Please visit the Account Upgrades page for more details.


    SUPPORT TMC