"Gear" Selection and regen braking control

Aptera Community Aptera Discussions "Gear" Selection and regen braking control

Aptera Community Aptera Discussions "Gear" Selection and regen braking control

  • "Gear" Selection and regen braking control

     George Hughes updated 3 months ago 7 Members · 10 Posts
  • Francis Giroux

    Member
    March 30, 2022 at 7:32 am

    Does anyone know what the gear selection mechanism is on the Aptera, and what choices there are? I expect choices of at least: Park, Forward, Neutral, and Reverse, but personally I would design it so there would also be few choices of degrees of regenerative braking (none, mild, medium, hard) without having to go to the main screen and select it on some non-permanent screen selection. On my Prius I can select neutral (no regen), forward (mild regen), reverse, and braking (medium regen for going down mountains). On my Honda Insight I can touch the brakes easily and get extra regen braking power (when in any forward gear) and even more regen with greater light pressure. If Aptera is to be a true efficiency vehicle it needs to have a choice of regen options (including neutral for coasting) at your fingertips (at least the neutral option) or on the brake pedal. I did see on the steering yoke of the beta mock-up a couple buttons, one with < > and the other with – +. I hope the – + button is for regen braking power and not volume control for music. Another good option for regen braking power control is to have the brake pedal (the pedal with – on it) programmed to be slight regen braking power when touched easily with increasing regen power when increasing pressure, until finally hard braking engages the mechanical brakes, but still having neutral (no regen) option with no brakes applied.

  • Joshua Rosen

    Member
    March 30, 2022 at 8:36 am

    Tesla only has two regen levels, low and standard. I came from the Volt to the Tesla, the Volt had regen paddles which Tesla doesn’t. I thought I’d miss the paddles but I don’t, Tesla has stronger regen and true one pedal driving which is better. Tesla also has three stopping modes, creep, roll and hold. I use hold, the other modes are there to mimic the behavior of an ICE car but I don’t think they are necessary. I really like one pedal driving, when you are coming to a stop you just lift your foot up and the car slows down. If you give it enough distance it can come to a complete stop without having to use the brake pedal. What one pedal driving doesn’t do is sudden stops, for that you need the friction brakes. Regen braking also doesn’t work if the battery is cold. In my Tesla I always precondition the car before leaving in the winter. They said they might not have that feature at launch but it’s critically important that they have it before winter 2023 because that’s when there will be Aptera owners in Northern states. I expect that all of the deliveries this year will be to Southern California where preheating the battery isn’t important.

    One more thing that the Volt had that Tesla doesn’t, blended braking. Chevy did a good job with blended braking, I never noticed a transition between regen and friction braking. I’ve seen a lot of reviews of other cars where they say that it doesn’t feel quite right. Tesla decided that simplicity was more important so the brake pedal is strictly friction braking. It’s hard to get blended braking to work well so I think Tesla made the right decision. If you have good one pedal braking then you shouldn’t need to touch the brake pedal except when you really have to and in that case you need the friction brakes anyway.

    I want them to follow Tesla’s lead, just a couple of regen levels with the standard level being strong regen. Concentrate on making one pedal driving work well and then keep things simple with the brake pedal, i.e. have it just do friction braking and make it so that you hardly ever need to use it.

    • George Hughes

      Member
      March 30, 2022 at 11:10 am

      I think they should follow Chevy’s lead on integrating the breaks with with regen. I would recommend the PRNDL standard with “D” being minimal regen and “L” being the default setting for ‘average’ regen. Adding paddles (+/- controls) and the integration of the regen brake pedal and the friction brakes that work in both the “D” and “L” setting.

      The advantage the Aptera has in this comes from the more robust regen capability of the Elaphe in-motor wheels largely because of the large diameter motor design, I understand, generates addition torque on acceleration and regen on deceleration. We should also be aware that the Elaphe wheels can actively even reverse direction (counter-acceleration) in real time.

      In understanding the dynamics of this mechanical contraption, recognize the essential mass of the moving parts of the electrical power train. Basically, all rotational momentum is concentrated on two circular ‘rotors’ that are attached only to the wheel and tire.

      The point is the rotational momentum all power in Aptera is structurally different than in any other EV or ICE vehicle and considering the ‘comparative lack of mass’ changing directions is mathematically different for Aptera in terms of the forces acting upon it. There has never been a vehicle with theoretically more innate manueverability in the history of modern wheeled vehicles.

      The rotational momentum of the Aptera is limited to what 30kg for the spinning parts of the motor and wheel; a figure nearly equaled by the tires and wheels of the typical ICE or even EV. But on other vehicles, you’ve got to count every moving part from the engine’s flywheel to spinning internal reduction gears, driveshafts, motor rotors, etc. all of which conspire to keep you going in the same direction you were going.

      When Aptera gets into the free world, free market, you’ll see someone develop a way – an app) to do a tank-turn U-ee at 50 mph … it will be a sight to see … and you probably will (in the movies). Yes, my prediction is that once Aptera gets rolling, it will increasingly be used in the movie business as a stunt-INSPIRING vehicle.

      • John Smith

        Member
        March 30, 2022 at 11:57 am

        In order to do a tank turn in an Aptera you will have to have the rear wheel pivot or caster which I don’t see happening.

        • George Hughes

          Member
          April 2, 2022 at 11:58 am

          … or be prepared to burn some rubber or offer an alternative.

          The burn rubber scenario would involve having(?) and using a rear-parking brake mechanism that the driver uses to throw the car into a skid. It is an old rally technique that is part of the evasive driving training designed to allow drivers to, if possible, do a 180-degree skid, reverse direction and escape from a dangers like an assassination … or making an appearance in an action flick … or negotiate a tight turn in a staged rally.

          There is also the option of adding a ‘lubricating spray fluid’ for the under-wheel area or, given the geometry of the ‘Aptera’ rear suspension, you could add an active element to the rear-wheel allowing it to put the wheel above the lower control arm which would be bolstered by a metal stand plate shaped in the form of a wing.

          This would even allow the Aptera to shed its front wheel fairings, replace the wheels with oversize ‘big balloon’ tires that are buoyant enough to float the Aptera awkwardly in the water but, with the winged rear suspension addition, you have a hydrofoil at the rear. (Think monster truck tires).

          Actually, while you may ridicule the idea of such modifications; the real revolutionary act is the creation of the right to repair Aptear from the get-go. It is the source of “inspiration”

  • kerbe2705

    Member
    March 30, 2022 at 8:37 am

    At present it’s a stalk on the steering column, most likely analogous to the one found on the Model 3. As it’s simply a switch I hope it will end-up on-screen, like the Model S.

  • Francis Giroux

    Member
    March 30, 2022 at 12:07 pm

    kerbe2705, thank you for a partial answer to my question. A stalk on the steering column. Right or left side? What selections are available? Most importantly is neutral/coasting without braking available?

    Joshua, I know a few parts from Tesla are in the Alphas but I hope Aptera doesn’t follow the inefficient engineering of Tesla. So far Aptera has avoided wasteful drive trains and gears, radiators and big mirrors. But I hope they realize the energy wasting tech of “one pedal driving.” Sure it is better than accelerating and cruising with power and using mechanical brakes for slowing down and stopping.

    But accelerating, cruising, and regen braking is only 75-90% efficient in converting battery potential energy into kenetic energy and back (each way), and as low at 56% efficient if you count both directions (battery to road speed and back to battery). Yeah cruising could be as good as 90% efficient. But coasting to a stop or at least coasting from cruise speed down to 20-30 mph approaching a turn or stop, can be 98% efficient at converting Kinetic energy into distance traveled (only wind resistance and rolling resistance are in play). If you are using regen “coasting” to capture that energy and put it back into the battery. You are down to that 75% efficiency.

    If we don’t have a zero energy use or capture coasting ability, we are wasting energy. The most efficient part of a drive for most drivers is cruise (could be as high as 90% at the 30 mph). However the most efficient part of a drive for an efficient driver with the right equipment is the coasting (slow deceleration without brake or regen) and could be as high as 98%. If acceleration has the same efficiency as cruising (90% max) then the most efficient driving technique is acceleration and coasting (called pulse and glide by hypermilers).

    And with an Aptera with excellent aerodynamics that barely slows you down while coasting, it is even more effective. Instead of cruising at 65mph on the Interstate, try accelerating to 70 mph and then coasting down to 60 mph before accelerating again, and especially try coasting to exits and sharp turns instead of using braking of any kind, and see how much better your efficiency gets. This is how I achieved 100 mpg on a Saturn SL1 and a Geo Metro. With the Aptera I expect to achieve 400 mile range with my 25 kwh battery and full solar.

    Give Aptera the ability to coast with zero energy input or regen.

    • IA -1

      Member
      March 31, 2022 at 5:40 am

      I hope Aptera will implement the coasting option too. I had a VW eGolf about 4 years ago and I was very pleased with the regenerative braking options:

      1. Gear selector in Drive – no resistance, you can coast.

      2. Move the gear selector from Drive to the left – you can choose the regenerative braking levels -+

      3. From there you can move the gear selector down to activate the maximum regenerative braking.

      Most of the time I was coasting and when I needed to brake, depending on the situation, I was using the regenerative braking levels or the B (max) level. I was using the actual brakes rarely.

      I hope Aptera would add -+ shift paddles at the steering wheel (terrible yoke) so you can change the regenerative braking level very fast.

  • Francis Giroux

    Member
    March 30, 2022 at 1:45 pm

    How to shift the Aptera.

    I found it. In Chris’s video with Kirsten Dirksen

    at https://www.youtube.com/watch?v=69_iKArvJBk&t=854s at 1:04 into the video Chris shows the “shifting” prindle with Park, Reverse, Neutral, and Drive as choices. But that was an Alpha with Tesla parts so whether that translates into the final version or not is still unknown. I also remember than there will be numerous setting for how aggressive the regen braking can be set, but that was done on the main screen. And I don’t know if that setting can be changed on the fly like I want it for greatest efficiency. Chris did say that the +- button can control “everything you can control on the center screen.” Sounds good as long as I can control the regen braking amount on the fly.

    • Steven G. Bueche

      Member
      March 31, 2022 at 4:12 am

      This by far is the most informative video (IMHO)

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