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Overall Design of an electric solar carHelp

  1. Mar 30, 2010 #1
    I have a 67 ranchero that I have been wanting to turn into a solar electric car, with panels over the back. I built an electric car with some friends in High School, but as with all things, Im sure the tech. has changed a bit over the past two years.

    I know how to set up the array and the fabrication that its going to take and I have a high torque trans axel that Im going to use, my question is about what components you would recomend for a mostly city car that will see highway speeds. *Ie, what voltage, and if there is a particular controller and motor(s)

    Thanks again!
     
  2. jcsd
  3. Apr 1, 2010 #2
    the costs and lack of "robustness' of PV panels may be a problem. I don't think you'd get a very good drive vs sit and charge ratio. there are a lot of plans on the net to "convert" a car to battery power
    that would be the first step
    then, instead of panels on the car, I'd build a carport, and recharge battery packs and exchange them

    dr
     
  4. Apr 1, 2010 #3

    mgb_phys

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    Before you get too excited
    1m^2 of the car, pointing straight at the sun at noon gets about 1.5Hp
    Regular solar panels are about 10% efficent, so the roof of your car gets about enough power to run a hair dryer.

    The solar powered cars you see from universities weigh about as much as the engine in your car, are super-aerodynamic and are covered with incredibly expensive super high efficency space grade solar panels.
     
  5. Apr 1, 2010 #4
    I realize that its not going to be able to drive only on the panels. Its more of a proof of concept project. At heart its a simple IC to electric conversion, which is the part I need a refresher on. The PV panels are just an added bonus. I was hoping that a full day charge could compensate or ideally more then offset the charge used to commute from my house to campus.
     
  6. Apr 1, 2010 #5
    Build your electric car, and add a grid-tied solar array to your house sized as a minimum to provide an average year of daily charges for your car (over size it to account for cloudy days, warm day efficiency drops, etc.) and plug it in at night to charge off the grid, while your solar array runs the meter back during sunny days.
     
  7. Apr 1, 2010 #6
    Ok guys your missing the point, ignore the solar panels, what is the best motor/contoller system around in a reasonable conversion price range and what voltage would you suggest.

    I have no house to mount panels on so.... the carport isn't an option, the panels are just something interesting I will add later and thought I would include it, Now back on topic>>>
     
  8. Apr 5, 2010 #7
    electric forklift has potential
    you also will need to change to a standard tranny to get the rpm range vs speed

    dr
     
  9. Apr 5, 2010 #8
    You could take the bus and spend your time studying.
     
  10. Apr 5, 2010 #9
    -dr Dodge, why wouldn't a transaxel work as a gear reduction method? the one Im using is out of a 63 tempest that Ive rebuilt and increased capacity on. I believe it is a 3 speed with 1.04 final drive, but Im not sure on that. It was orignally attached via a torque tube to a v8. Is there something Im nopt taking into acount.

    -Holmz, Im studying electrical engineering ;) getting this thing going is homework for me

    Thanks again
     
  11. Apr 5, 2010 #10
    I am totally confused. A '63 pontiac tempest does not have a transaxle, only a rear axle. unless this is a "non US car" thsat I am unfamiliar with. You need to be able to switch between gears, and using an automatic transmission will cause big efficiency loses. You would have to run the pump in the tranny full time in addition to the power needed to run down the road

    dr
     
  12. Apr 5, 2010 #11
    the 63 and 64 pontiac tempest lemans have a three speed auto transaxel with independant rear suspension which was one of the reasons they were popular with racers because of the 50/50 weight distribution. It was the popularity of this the lead to the creation of the gto, though the gto lost the transaxel.
    I hadn't thought about the front pump....would it cause more power loss then the roughly 23% most rear wheel drive cars lose through intrinsic power loss?
     
  13. Apr 6, 2010 #12
    well, I stand corrected. (but I am used to that...lol)

    I just researched the tempest, very interesting! I think if I were to do this, first I would consider how to pressurize the trans. possibly a 2nd motor/hydraulic pump combo with an accumulator for the shift control. I would also seriously consider not using the ranchero chassis. you can save a ton of weight (literally) by making a purpose built chassis assy. (a vw "rail buggy" may be a good sacrificial donor, or an indy car style layout)
    there are other things to think about
    battery weight, and placement. you will end up very heavy, and I do not know how much the axles themselves can carry. also, replacement parts will pricey, being as how rare the transaxle is (couldn't find a single one for sale on the net) I have thought about using an "import" manual front transaxle in the rear, and then simple adaption to the half shafts, and late model 4 x 4 front suspension for arms, springs, and hubs. that gets the load carrying capacity up there very nice.

    as far as the commute, it would be cheaper to actually by the bus...lol
    batteries, control system, chassis construction, machine shop time, and motors are all pricey
    I have been looking for a cheap electric fork lift to build a similar project out of, (with no luck)
    but quite honestly, IMHO, the concept of it saving any money is a pipe dream
    and if you buy the power, its not really very green either

    dr
     
  14. Apr 6, 2010 #13
    Whats the point? A very good mental excerise. Totally crap as a practical car. There is little point in doing a proof of concept as we already know the concept is sound.

    Electric cars (even specifically designed ones) are pretty rubbish, at the moment purely becuase batteries are so crap and yet very expensive. They are even worse when you taken them beyong inner city speeds.
     
  15. Apr 6, 2010 #14
    and a darned good way to spend big piles of cash, and divert your time that (in the case of students, especially) should be used for other things.
    the only reason I thought about a homebuilt one is that my wife works less than 1 mile from the house, (as is the beer store) and I figure I can run used reconditioned batteries (I have no shortage ending up with them...lol)
    and even at that, you can't build one for what a used GEM goes for ($3500-8500)

    dr
     
  16. Apr 6, 2010 #15
    Dr dodge- well within that statement you basically answered my question. Do you think a used forklift is the best source of the motor and controler? would one of those have enough power? As far as funds, im not to worried. the only thing that is going to cost me is the motor and contoller and maybe the wiring. I have access to literally hundreds of batteries and a free machine shop with junkyard that is helping me out in exchange for free advertisement.

    - as far as weight, the 67 ranchero uses a front unibody design so it only has a frame under the rear, which i have already chopped and built an tubular frame to accept the rear axel and adjustable suspension. I have about $3k to spend on the motor and controller and im very resourceful when it comes to getting parts.

    oh yea and as far as parts for the transsaxel, I have 2 working plus one for parts ;)
    like I said, Im pretty good at finding things
     
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