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From Electrek: Tesla Model 3: Elon Musk virtually kills the possibility of a solar roof option

Discussion in 'News from Electrek.co' started by RSSFeed, Jul 16, 2017.

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  1. RSSFeed

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  2. Badback

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    #2 Badback, Jul 16, 2017
    Last edited: Jul 17, 2017
    I don't understand why everyone thinks that a solar array has to charge the main battery. How about if it simply runs a fan to keep the interior (relatively) cool on a hot day. When the sun is shining on the car, the interior is heating up. A fan could keep the inside close to the temperature of the outside. Same idea for cold weather, a small heater could make the inside just a little bit more pleasant. So it isn't effective all of the time, so what?
     
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    • Jayc

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      And that's what the solar roof option in 2011 prius plug in does - keeps cabin cool so a/c has to work less. Makes a big difference in hotter parts of the world.

      Now about charging a 60+kwh battery from a solar roof on a car - that's a no go from first principles unless you work for marketing. Actually I was surprised when EM said it's an interesting idea but then look back at the context in which that statement was made - it was when Tesla was in the process of acquiring solacity and it makes total sense why Musk said that.
       
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      • garsh

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        It's still a silly gimmick.

        Just use the main battery to run that fan. The cost of that solar panel & accompanying manufacturing complexity just isn't worth that small benefit. Maybe if you leave your car outside while unplugged for more than two weaks at a time, it will make sense, but that's about it.
         
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        • ModFather

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          Call me @stupid but an insulated car cover works much better (at a fraction of the cost) than a solar array on the roof in a place like SoCal where the temperatures have been 100 to 110F the last three weeks. And no pesky tree sap, acid rain, or other nasties as a side benefit too. If can incorporate extra padding along the belt line to absorb door dings. ARE YOU LISTENING AFTERMARKET GUYS? [​IMG]

          I think the BIG advantage to a car roof solar array is when driving. You drive in the sun for a period of time and your EV batteries are recharged. But this will come in the not too distant future when battery technology evolves and improves. EM knows what he is doing and he is not going to push a product on the public, despite how SEXY it might sound, that isn't ready for prime time yet. But believe me, a far better version is under development at TESLA as we post.
           
        • Topher

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          #6 Topher, Jul 16, 2017
          Last edited: Jul 16, 2017
          The trouble is that just letting the sun through the window would warm the car more than having panels, converting to electricity, then converting to heat.

          But that never happens. You drive in the sun for a period of time and your batteries are depleted, just minutely less than they would be otherwise. If you drive at 60 mph, your range after an hour will be 199.1 instead of 198.3 (From 215)

          [Actually, if you drive slowly enough, you could have your battery level increase. 0.89 MPH]

          By the way, battery technology makes no difference here. Solar PV improvements would help a little. Like 201.5 miles instead.

          Thank you kindly.
           
        • ModFather

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          @Topher you completely missed my point. I agree it cannot be done with today's battery technology. It will require a battery or some other technology of the future.
          I expect that batteries will come closer to replenishing themselves at a rate that energy is used. It's only a pipe dream but cars will be powered by the sun while under power, in some format, in the future.
           
        • Topher

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          Nope. You missed mine. PERFECT batteries will not help. NO battery technology even impinges on the equations for the problem. The problems are 1) Sunlight energy is diffuse. 1kWh per hour per meter². Best possible case. 2) People want big heavy cars. I can get you a car NOW that meets the spec, look up Solar-Racers. You just won't like riding in it.

          Thank you kindly.
           
        • Topher

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          They already do. Maximum recharge rate and maximum discharge rate are about the same for Li-ion batteries.

          Thank you kindly.
           
        • ModFather

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          #10 ModFather, Jul 16, 2017
          Last edited: Jul 16, 2017
          I already said I agree with you, "NO current battery technology even impinges on the equations for the problem" Battery technology is not study state, it is constantly evolving and newer and different technologies are evolving. As far as people wanting heavy cars, people wanted ICE cars too until something better was offered. The weight of cars can be reduced, the technology is there, we just have to get the cost down as was possible for solar panels, batteries for EV cars, and laptop computers I want an EV racer that I will like riding in and the model 3 is the best option available right now. But there will be better options in the future.

          The times, they are a changin' You can either get onboard or get stuck in the past. Your choice.

          I am not going to continue to debate this further on this forum. If you want to debate, send me a PM.
           
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          • Topher

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            Please don't misquote me, you still aren't getting it. NO BATTERY TECHNOLOGY AT ALL, EVER, CAN EVER MAKE A DIFFERENCE. Current, future, magical, nothing. NONE. Batteries don't MATTER. AT ALL. You can create a car WITHOUT batteries, just solar panels and electric motors if you want. Battery improvements are no more useful than a tastier banana.

            Power In: (size, angle, orientation, efficiency of the panels, insolation)
            Power Out: (Weight, Cd, Frontal Area, Rolling Resistance, etc.)

            That's it. Batteries aren't in the equations anywhere.

            Thank you kindly.
             

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