Solar Charging While Driving

Aptera Community Aptera Discussions Solar Charging While Driving

Aptera Community Aptera Discussions Solar Charging While Driving

  • Solar Charging While Driving

     Alain Chuzel updated 6 days, 19 hours ago 16 Members · 25 Posts
  • Ronald Travisano

    Member
    June 29, 2022 at 11:50 am

    Is the rate of charging from the onboard solar cells the same while actually in motion as apposed to parked with the Aptera off?

  • Len Nowak

    Moderator
    June 29, 2022 at 12:09 pm

    Like everything… TBC but they said to think of it as a trickle charger where the sun properly exposed to the panels will produce the range

    The Gamma should have solar more solar panels and I assume the solar advances they have been working on.

    They said they few more spots for a couple more solar cells.

    I believe originally a full solar was 180 solar cells

    • Ronald Travisano

      Member
      June 29, 2022 at 12:13 pm

      Sure, trickle charging. I’m just curious if I’m in full sun on the highway is it the same trickle as if in full sun parked. Not sure if the act of engaging the batteries for driving will slow the rate of charging.

      • Curtis Cibinel

        Member
        July 22, 2022 at 8:09 am

        At about 15 mph the draw per the physics is 33.9 wh/m. Combined with 200w for computers and screens and this accounts for the 700w solar generation. Admittedly this has assumptions but it matches range expectations and effectively models all ranges (very similar to those numbers by Aptera Owners club and motor matchup)

    • kerbe2705

      Member
      July 21, 2022 at 11:40 am

      @Len Nowak Just to be a stickler and a PITA, Gamma will have the same number of solar PANELS but a greater number of solar CELLS in those panels.

  • Paul Carlucci

    Member
    June 29, 2022 at 2:46 pm

    Might even work a little better since the air flowing over the panels should keep them closer to ambient temperature given that panels make slightly less power the hotter they get. We’re talking a few percentage points here though.

  • Harry Parker

    Moderator
    June 30, 2022 at 9:29 am

    The solar panels add to the power coming from the batteries as you drive down the road.

    As Paul mentioned, the rate of energy production from the panels may be even higher when you’re moving due to air cooling effects. However, except when you’re braking or going downhill, the motors are usually drawing more power than the solar panels are generating.

    So, the solar panels will just provide part of the power the Aptera needs while its moving, except at very slow speeds and decelerating, reducing the energy drain on the battery but not eliminating it.

    The full solar option is rated at 700 watts. Since 1000 watts-hours will take Aptera 10 miles, 700 watt-hours will take Aptera 7 miles. So the power of the full Sun alone is enough to push the Aptera at about 7 miles per hour (not counting a few percent lost from inefficiencies in the power conversion electronics). Driving slower than that average speed and you would be charging the batteries while you drive in the sunlight!

    • Qiang Fu

      Member
      June 30, 2022 at 8:05 pm

      Since 10mile/kwh is EPA at much higher speed than 7 mile/hour, I would expect Aptera can go more than 7 mile/hour constant speed assuming getting full 700w from sun.

      • Harry Parker

        Moderator
        July 1, 2022 at 10:30 am

        Yes. That’s a good point. The question is, how much is the drag reduced at those lower speeds?

        I’ve read that the EPA average speed is about 45 mph, but drag is nonlinear with speed, and some power is used even when the car is stopped, running the electronics.

        Of course other factors make a big difference, such as incline and wind speed and whether heat or cooling energy is being used. At 7 mph, the wind speed could easily be faster than the car is going, doubling or reducing to zero the relative air speed depending on its direction.

      • Dan Stevens

        Member
        July 22, 2022 at 11:34 am

        Figure 40 miles of range from solar a day.
        5 solar hours a day (average)
        40 miles divided by 5 hours = 8 mph.

        Definitely faster than 7. No land speed record being set here though.

    • Erick Vega

      Member
      July 20, 2022 at 10:03 am

      What I am more interested about is the circuitry used to charge the batteries during driving. Is this actually occurring or are you bypassing “charging” and using solar panel wattage directly to the motor during driving.

      Also, will we be allowed to purchase and mount more solar panels and connect to the charging system for even more range or will we be software locked to a certain Solar wattage?

      • Dennis Swaney

        Member
        July 20, 2022 at 5:09 pm

        Where else would you mount them? The four areas are already completely covered (if you opted for the full coverage).

      • Harry Parker

        Moderator
        July 21, 2022 at 10:43 am

        The Aptera solar charging circuit is very similar to a home battery charging circuit. Nothing is preventing the power from the solar panels going out to power the car and charging the battery at the same time, depending on the car’s power demands that instant. If the car is going at highway speeds the motors will draw more power than the panels can deliver so that solar power will be added to power from the battery. However, as soon as you start slowing down, the motors won’t need the solar power so the batteries will recharge using sunlight and what’s produced by regenerative braking.

        Re. extra solar panels: the CEOs have confirmed in a video that they will provide a connector for external panels, but have not provided specs on what range of voltage, current and power those panels must be. Perhaps up to another 700 watts? However I picture those as camping panels placed on the ground rather than mounted on the car.

        • This reply was modified 2 weeks, 3 days ago by  Harry Parker.
        • John Hermann

          Member
          July 21, 2022 at 11:16 am

          In my current vehicles I use a sun shade in the windshield to keep the cabin temps down and protect the interior. Something in that form factor with integrated solar charging might be an interesting dual-purpose option. It would potentially offer more surface area for solar cells, but may negate or eliminate the cells on the dashboard.

          • kerbe2705

            Member
            July 21, 2022 at 11:38 am

            @John Hermann Another option would be a solar shade that, instead of pressing against the windshield, attaches along the top of the windshield but then attaches to the dashboard on the interior side of the solar panel, hanging nearly vertically.

            • Curtis Cibinel

              Member
              July 21, 2022 at 6:02 pm

              So basically half a shower curtain and some command strip hooks?

    • kerbe2705

      Member
      July 21, 2022 at 11:46 am

      @Harry Parker The phrase, “push Aptera down the road”, implies that the solar panels can generate enough current to turn Aptera’s motors without the intercession of a storage battery to accumulate the power the cells generate. What the panels can do is generate enough power to charge the battery so that it can push Aptera down the road but, even in full sunlight at the optimal angle to the cells, the panels can’t generate enough current to turn Aptera’s two or three fifty kW motors directly.


      • Harry Parker

        Moderator
        July 21, 2022 at 5:32 pm

        Kerbe, yes, that’s what I meant.

        To be precise, solar panels are connected to a Maximum Power Point Tracking (MPPT) solar charge controller. That charge controller is connected to the battery. Also connected to the battery are the motor controllers. So is a DC to DC converter that provides a lower voltage to the other electronics such as the lights, displays and radios. With regenerative braking, the power can flow either way to and from those motor controllers.

        Whether the battery is getting charged or discharged depends on whether the solar charge controller is putting out more or less power than the car needs at any instant in time.

        Those 50 kW motors only draw those 50 kW each when you floor your Aptera. Going steady down the road they only use a small fraction of that. The Aptera uses 0.1 KWH to go 1 mile, at the average speed of the EPA test cycle, ~45 mph. So at a steady 45 mph on level ground the car is drawing about 4.5 KW, still much more than the 0.7 KW the solar panels produce.

        In full Sun, when the panels are producing their 0.7 KW, the the car will draw about 4.5 – 0.7 = 3.8 KW from the battery at a steady 45 mph. At some lower steady speed the car will need only what solar panels provide. At even lower speeds the solar panels will charge the battery.

        • Alain Chuzel

          Member
          July 22, 2022 at 6:21 am

          I’m glad you wrote this. I get tired of repeating it…..

        • Steve Wanamaker

          Member
          July 24, 2022 at 10:59 am

          “The Aptera uses 0.1 KWH to go 1 mile, at the average speed of the EPA test cycle, ~45 mph.”

          I’m new in my research and this is the first time I have come across this here. The 45 mph test speed is a very important figure. Most people have been thinking they will get 250/400/600/1000 mi range when taking trips. If this is really only at 45 mph, then it deserves it’s own topic. People need to have a better idea of what the range actually is at highway speeds so that they can make the right buying decisions.

          • OZ (It’s OZ, Just OZ)

            Member
            July 24, 2022 at 11:04 am

            You haven’t come across anything, unless it can be directly sourced back to an Aptera statement. There is so much here say and wishful thinking in this and all the other forums on various sites, you’d be lucky to have any idea of what an Aptera looks like.

      • Curtis Cibinel

        Member
        July 22, 2022 at 8:06 am

        Dupe

  • Sam Giedzinski

    Member
    August 1, 2022 at 11:12 am

    Solar farm engineer here! Not sure if this info has been said, but the wattage rating of solar cells is based on Standard Test Conditions (irradiance of 1000 W/m^2, which simulates an average sunny day). The 700-watt rating from Aptera’s cells will differ a lot from real use. If you’re really lucky, you could get 1 kW of power or more sometimes, but to account for shade, cell angle, and climate conditions… I wouldn’t count on much more than 500 W for full solar most of the time, at least if we’re trying to make conservative calculations.

    Hope this helps! Looking forward to the day when we can check all these numbers for real 🙂

    • Jonah Jorgenson

      Member
      August 1, 2022 at 1:56 pm

      Always nice to have a professional expert way in.

      I agree the 700 watt rating is under the best conditions and marketing optimistic. I would not expect 700 watts even where I live in FL. Hence I think the reason Aptera added some extra cells.

    • Alain Chuzel

      Member
      August 1, 2022 at 2:04 pm

      Welcome.

      While not in exactly the same terms, much of what you say has, indeed, been said but it’s always nice to get some additional experts weighing in. My expertise is in design/build of specialty solar panels/module and much of my work has been for vehicles with compound curve arrays (solar race cars).

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