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New Solar Panels for Hybrid Cars Improve MPG

Discussion in 'Prius, Hybrid, EV and Alt-Fuel News' started by Kiloran, Dec 7, 2005.

  1. tripp

    tripp Which it's a 'ybrid, ain't it?

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    There are several non-silicon based approaches that would probably work out well in this application. The real drawback to them right now is that they just don't come close to the efficiency of the silicon cells (mono or poly crystalline). That's changing though and most of these things are much cheaper to produce.

    Once solar gets cheap enough I think that the PHEV is going to be a spectacular solution for the transportation sector. I could see having a solar array at home that pumped energy into a flywheel storage system. With the advances in battery technology that we've already seen (the really fast charging rate) you could recharge the car very quickly without have to have your house rewired with more juice. Integrated solar panels like skruse mentioned would help extend the range of the car while it's away. Then everyone will be fighting for the sunny spots in the parking lot.
     
  2. viking31

    viking31 Member

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    Whoa!!

    Think about the output of these cells. 30 watts. That is LESS then one headlight consumes on low beam for most cars. And I assume that is under ideal sunny conditions (overhead and not morning or evening sun).

    One HP equals 746 watts under theoretical perfect power translation. So even with theoretical perfect conditions of an eight-hour charge and no charging losses we gain 240 watts (although we know we will expect much less in reality). Under full load the 76 HP ICE is theoretically capable of generating over 56,000 watts of power. So how much fuel could be used by the ICE generating the total solar panels energy total “perfect day†equivalent of 240 watts? Perhaps single digit ounces if that? Remember, at current prices an ounce of fuel is now less than 2 cents.

    This means under our assumed perfect conditions we could expect to utilize about 1 HP extra for our Prius for 20 minutes of driving (or 1/3 HP more for one hour of driving, or…). And that is going to give us a 10% increase in mileage? I think not. And even if it did as the manufacturer claims, another poster showed the enormous cost versus fuel saved (and that calculation did not take into account the time value money costs too).

    A neat idea but I think it is FAR FAR from any practical consideration.

    Rick
    West Central FL

    Soon to take delivery of a Silver package #4 2006. Arrghh! It will be on the dealers lot this weekend but got to wait till next year.
     
  3. jbarnhart

    jbarnhart New Member

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    30W output? 10% milage improvement? Something doesn't add up here. I presume we could run our cars for free if we supplied 300W? What a deal...
     
  4. clett

    clett New Member

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    It looks like there's about 0.4 m2 of roof covered (15 cm wide by 1.3 m x 2?).

    30 watts peak from 0.4 m2 is equal to about 7.5% efficient.

    It's nice that they're flush and curved etc, but 7.5% is nowhere near the 21% efficiency of Sunpower A300 cells.

    Cover the roof and bonnet in A300s and then you could get a reasonable amount of energy - almost 1 kW peak, which over a day could give you up to 5 kWh total. This would be enough for 20 miles EV range but, as a previous poster mentioned, the existing 1.3 kWh battery HV battery is far too small to absorb all this energy.

    Steve Lapp's solar Prius manages a 10% improvement in gas mileage, but uses much more solar cell to achieve it and has 360 watts peak!

    I believe Steve's claims may be more accurate than Solatec's!

    [Edited to fix link]
     
  5. efusco

    efusco Moderator Emeritus
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    I just sent an e-mail to the president of Solatec LLC and invited him to address some of our concerns. We'll see.
     
  6. efusco

    efusco Moderator Emeritus
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    My first e-mail to Mr. Fuller:
    His first response:

    My reply to his e-mail:
     
  7. windstrings

    windstrings Certified Prius Breeder

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    I'll let my tax credit pay for it!

    Humm, it almost looks like theres room for 3 or even 4 on the roof.... the antennea may be in the way on one... :(
    What color is that car? Salsa or barcelona?

    Thanks for the post Kiloran.... looks like a good one. :D
     
  8. tripp

    tripp Which it's a 'ybrid, ain't it?

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    I bet that a switched reluctance generator would do far more and for way less. Again, it would have to be something designed into the car but would pay serious dividends in battery (traction) recharging. A typical car would make use of a 6kW device. The ICE could recharge the battery w/o use of MG1. The waste heat from the exhaust would accomplish the task. Seems like that would improve MPG a bit. Even in a regular car the savings could be as much as 5%.
     
  9. NuShrike

    NuShrike Active Member

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    Ya, barring rock chips. You could definitely put a strip across the rear spoiler too.
     
  10. windstrings

    windstrings Certified Prius Breeder

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    I'm in total agreement with Evan,
    First of all if we are talking about charging the 12V system, this must be some sort of a gimmik.
    18V photovoltaic is for the 12 Vside...
    1. Sitting all day in a parking lot, you cannot store the energy available from the hours of exposure in the sun , without "many" batteries.... the one 12V doesn't have enough storage for squat.
    2. He is basically saying the 12V accessory side uses 10% of your gasoline! and to remove that use gives you back 10% gas mileage!... I suspect not.
    3. It is also limited to what you catch while driving, because the 12V battery is never gets low as the inverter keeps it charged.... so as small as it is, the 12V battery is not even a decent basin to hold excess power at all?
    4. At best, all this system would do is power 30 watts worth of your accessories for free "only" while in direct sunlight?.. whoop pee? Thats a little better than your dome light!... or half the output of "one" headlight!
    5. Only 2 strips?... there just isn't that much power derived from that much solar exposure.
    6. At night, you get nothing at all!
    7. If this was a 201V configuration and could charge the main batteries... even then you would only get an extra 2 - 3 miles a day free driving. Again, you need more storage even with the main batteries?

    I must be missing something big here.. I hope the manufacturer can clear the mud!.... cause it sure looks muddy in my pond!
     
  11. 200Volts

    200Volts Member

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    I think it's a rip off. Compare the prices to solar panels for your house:
    175 Watts for only $875 !!!!!!!
    http://www.partsonsale.com/sharp.html

    SHARP NT-175U1 High power 175 watt module which uses 125mm square multi crystal silicon solar cells with 13.5 % module efficiency.
    Maximum power is 4.95 Amps @ 35.4 Volts peak. Dimensions 62.01" x 32.52" x 1.81" Weight 38 LBS TRCK

    If you added some kind of step up transformer to charge the 208V battery then you would loose more efficiency. These are already wired in series to generate 24 - 35V. So you would need 96 sq. feet of solar cells to "directly" charge the HV battery (assuming 30V per panel now).
    Obviously more efficent solar cells are one answer.
     
  12. tripp

    tripp Which it's a 'ybrid, ain't it?

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    yes, but those are rigid poly or mono crystalline silicon panels. They are much higher efficiency but are ridig and heavy. It does seem like a waste of money and it seems that the claims cannot be backed up with controlled testing, just "I drove around and things got better". For a product that costs $2k I wanna see real numbers not warm fzzies.
     
  13. efusco

    efusco Moderator Emeritus
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    I hadn't really thought about those points. Unless the designer has created a means that actually prevents the 12v battery from being charged via the HB battery while being charged by the solar panels (ie the system gives preference to charge recieved via the solar panels) then it's entirely possible that only 50% of the charging is actually coming from the solar panels, or potentially less than that if it can't supply the charge as quickly as the HV does.

    IOW, to truely take full advantage you'd need a circuit that shuts off charging from the HV battery to the 12v when adequate charge is being delivered from the solar but would permit additional charge from the HV when the solar was unable to deliver all or part of the charge.

    I've not yet recieved a reply to my second e-mail.
     
  14. efusco

    efusco Moderator Emeritus
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    No kidding. Maybe this guy bought the car last fall, got 45mpg until May when he installed the PV panels and 'miraculously' his mpg jumped to 55mpg in the summer--give all the credit to the PVs and then try to sell them for 2 grand.

    I honestly hope he comes on and posts some technical data and test results that show our speculation to be wrong, but I just don't see, physically, this could possibly make a signficant difference...maybe a small measurable difference, but not a big enough one to justify $2200.

    One can easily buy small PV panels from a number of sources that can be wired directly to the battery and placed in the cargo area of the Prius that would total 30 watts for under a $200 and do just as good a job of maintaining the 12v battery.
     
  15. DocVijay

    DocVijay Active Member

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    You could always get a flatbed trailer and bolt on a bunch of those units, then just tow and go.
     
  16. skew

    skew Junior Member

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    Maybe while installing the panels they looked at the tires and said humm they look alittle low I'll add some air to them. Presto the panels are incredible we must sell them :)
     
  17. windstrings

    windstrings Certified Prius Breeder

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    What I keep remembering is it takes about 740 watts to equal just "one" horsepower, and thats if you have a perfect conversion to kinetic energy and no system is perfect!.. but assuming it was.... 740 watts divided by 30watts equals 24.66.
    So the solar panel makes 1/25th of a horsepower under direct sunlight at any given moment!.... the traction battery can deliver 28 horsepower by itself! this seems to be a waste of time and alot of money unless I'm missing something!
     
  18. moonbeam

    moonbeam New Member

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    I am an accomplished chef. My knife skills are far faster than using a food processor. I have one knife that I only use for veggies, but last Saturday it said "Feed me", and zapped though the 1/4 inch dice of an onion and it my left hand pinky. At first, it didn't hurt, or even bleed. It is a *very* sharp professional knife. I put on a band aid, and it started to bleed, and really hurt. Three bandages later, and a half hour in denial, I went to emergency. Seven stiches later, they told me I made the right choice.

    William
     
  19. altaskier

    altaskier New Member

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    According to my calculations, filling the roof and the hood of the Prius with 15% efficient solar panels would supply you with the equivalent of about 1/9 of a gallon of gas per day (double that in summer in the southwest). See this web page
     
  20. efusco

    efusco Moderator Emeritus
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    I want to become an accomplished chef...wanna job swap for a week?