Curious about resistave heating and range.

Aptera Community Aptera Discussions Curious about resistave heating and range.

Aptera Community Aptera Discussions Curious about resistave heating and range.

  • Curious about resistave heating and range.

  • john higgison Higgison

    Member
    February 27, 2022 at 1:14 pm

    I’m wondering how much the resistave heating will take from range? Sine the car is so efficient it needs a battery 1/4 the size.. makes sense and I think they said they can maintain hwy speeds with 1500 watts… if that is that case then what happens if you have to have the heater on in winter and it’s drawing a load of watts too? I imagine it’d be a minimum of 700 watts to keep the inside of the car warm, basically a hair dryer on medium. Will that kill the range by a sizable mount since its a small battery?

  • Oz (It’s Oz, just Oz)

    Member
    February 27, 2022 at 3:31 pm

    Without regard to the exact method that will be used (Seat/Fan/Whatever), the thick composite body should offer excellent insulative properties, when a temperature is achieved, by whatever means, much less energy should be required to maintain it.

  • Curtis Cibinel

    Member
    February 27, 2022 at 3:38 pm

    Heated seats and wheel (or yoke) will help. The interior is overall still smaller than something like a model 3 but if the heater is being blasted it will definitely impact range substantially. Youtubers have looked at long trips and used ~15-20% more energy in a model 3 (with resistive heating).

    I think 700W might actually be underestimating the heating needs in really cold temperatures. The motors will use 5-6KW while driving at 60mph. MotorMatchup’s tool seems to expect 3KW from heating at 20F / -7C so that is 35% range loss.

    FYI: Between losses from heating, avoiding 0-100% for the battery and mountain roads I am reserving a vehicle with a range in miles that will meet my needs in KM (400km will be fine for me so I ordered the 400 mile model).
    MotorMatchup (includes Aux Power Slider ): https://www.motormatchup.com/efficiency

    Note: I can’t deep link the Aptera specifically. Select it and hit search.

    My Range Calculator: (does not include auxiliary load but has drivetrain losses):
    https://docs.google.com/spreadsheets/d/1Tuu7avKH2dS_JPk7aiP2av09a1f1WE0OvvNH6fdHpiQ/edit#gid=1285203539

    Note: The different calculations have different limitations. They are assuming a 0.007 rolling drag coefficient which may be low and don’t account for drivetrain efficiency but my calculations don’t factor in any auxiliary power load at all. They also don’t factor in battery reserve but do include headwind 🤣. Both include elevation and its kinda funny how much more range an EV will get at 10,000 feet. The engineers at Aptera undoubtedly have the most accurate models internally. I have no idea who provided the numbers for to MotorMatchup; their assumptions for weight and frontal area are very similar to mine

    • Dennis Swaney

      Member
      May 10, 2022 at 8:17 pm

      ” I am reserving a vehicle with a range in miles that will meet my needs in KM (400km will be fine for me so I ordered the 400 mile model).”

      Curtis, 250 miles is just over 402 KM so that model should meet your needs though the 400 miles would give you 646KM, which is a nice cushion.

  • Francis Giroux

    Member
    February 27, 2022 at 5:13 pm

    I know everybody is worried about range loss in winter conditions. Have you even noticed your reduced range in the winter with an ICE vehicle. I drive two of the best hybrids ever sold, Honda Insight (first generation) and Toyota Prius. Both have winter reduction in fuel mileage of what I expect with the Aptera, approaching 30%. I don’t use my heater much because I park my cars out in the sub-zero night weather and don’t warm them up before driving. Most of my trips are under 30 miles so the vehicle is just warming up when I get to my destination. I just keep dressed warm and use only the defrost. So my Aptera is not expected to do any worse than the two hybrids, even with resistive heating. The heated seat and wheel (yoke) will be nice though.

  • Gary Greenway

    Member
    February 27, 2022 at 5:59 pm

    Here’s a test Car and Driver did on a Tesla resistive heater. https://www.caranddriver.com/news/a31739529/how-much-does-climate-control-affect-ev-range/

  • Francis Giroux

    Member
    February 27, 2022 at 6:45 pm

    Yeah, this article shows a 26% reduction in range between no heat and full power heat plus all five heated seats on highest setting. My own experience mentioned above was more reduction in mileage (range) in two hybrid ICE cars in the winter. Like I expressed above, I expect the Aptera to do as good or better than my ICE cars, despite everybody’s concerns about range reduction from using electric heat in the winter. What most are not taking into account is that the internal combustion engine (ICE) loses a lot of efficiency in the cold, and in my case, more that a Tesla with resistive heating. And I wasn’t even blowing the heat full blast and didn’t even have heated seats. Aptera will do just fine.

  • Jeffrey May

    Member
    February 27, 2022 at 9:55 pm

    Curtis already chimed in on the fact that 1500W is way less than would actually be required to maintain highway speeds, but I just wanted to reiterate that point. If you accept Aptera’s rough estimate of 100Wh/mile, it’d be 6000W at 60mph (for example). More at higher speeds.

    Even still… yes, resistive cabin heat could have a significant impact on winter efficiency and range. But with a 400+ mile range, it might not be that big of a factor in real life. (Although you’re not going to achieve rated range in the winter anyway, regardless of heater usage or heater type.)

    I worry much more about their unproven cooling system architecture than I do winter heating efficiency.

    • This reply was modified 4 months ago by  Jeffrey May.
  • john higgison Higgison

    Member
    February 28, 2022 at 9:09 am

    Thanks for the amazing posts everyone.

    Not sure where I got the 1500 watts to maintain hwy speed… thought I heard it on a video.. maybe the jay lenno one. At the time I remember thinking it made sense since they say they have the drag of an F150 mirror.

    I might order the 600 mile pkg instead… just to make sure I’m covered in the winter. Sometimes I drive from Ottawa to Sudbury, 500km, and it gets pretty damn cold here in winter. I imagine not fully charging and fully draining the battery is wise so… 600mile is probably the right choice for me.

    • John Malcom

      Member
      March 1, 2022 at 11:29 am

      Better to be safe than sorry in Canadian winters. Probably wise too as the batter will degrade over a number of years and you should have sufficient power to last quite a while.

  • Michael Klensch

    Member
    February 28, 2022 at 10:18 am

    The 25%-30% number that you’ve been hearing is about dead on in my experience. I have a 2014 Nissan Leaf S that has a resistive heater, and I typically see about this amount of loss during the winter. I live in Alaska, and so my loss might be a bit more than most people’s. I do use my heated steering wheel and seats all the time and they are a big help. My winters are cold enough that a heat pump would not work well, and I’m glad to have the resistive heater. Of course, depending on where you live, I think factoring in 25-30 percent loss is a good benchmark.

    • Lou Verner

      Member
      February 28, 2022 at 7:59 pm

      This may have come up in an older forum, but worth mentioning again: The greatest amount of cubic space in the Aptera is in the hatch area, behind the seats. If there was a means of closing off that space from the cabin, any heat source would only have to heat that much smaller space, thereby greatly reducing use of battery and range. A simple zipper/Velcro closure should be simple to design!

      • Curtis Cibinel

        Member
        February 28, 2022 at 8:06 pm

        This seems like something that someone with a focus on efficiency and a setting machine could make ; essentially some canvas, adhesive, and zipper/ snaps. Cleaning the residue off of you decided to remove it could be messy.

        I would think this wouldn’t save much power on trips over an hour (depending on thickness and seal quality). Eventually heat will equalize.

      • Michael Klensch

        Member
        March 1, 2022 at 8:16 am

        Brilliant idea Lou. Perhaps some reflective bubble-wrap insulation (like the type used for windshields to keep out the sun’s heat) would make a good material. I think Curtis hit on some great ideas for fastening. Perhaps some strategically placed Velcro would also work?

        • Curtis Cibinel

          Member
          March 1, 2022 at 8:51 am

          The issue with velcro is that it inevitably degrade with use especially as dirt gets in it. You would need to use heat to remove and redo it after a while (maybe a few years). I have dogs and dirty camping gear so my car is never clean.

          As I said before this will help on shorter trips but once it’s long enough for the temperature in back to warm up the end result is the same. If you don’t mind sealing it of permanently obviously the thermal insulation could be a lot higher.

      • John Malcom

        Member
        March 1, 2022 at 9:17 am

        My wife and I owned/drove Gen1 Honda insight. Same form factor as the Aptera. My wife had the same idea and fashioned a barrier out of part of a cover to the hot tub. About two inches thick. It worked fine for insulating front area from cargo space (Maybe placebo effect) We live in FL so used it to reduce the amount of airconditioning required. We had to discontinue using it after getting a ticket for blocking view out of the back. Moving forward to current day, Aptera solves that issued with a rearview camera. A good DIY project for those that believe it might be useful for them.

        The only downside I can see is it may affect the climate conditioning (matching outside ambient temp in the cabin) in hot weather when the vehicle is not occupied. Of course need not use it depending on outside temps

        • Lou Verner

          Member
          March 1, 2022 at 10:49 am

          Proof of concept – or as the great Mark Twain said, “There’s nothing so annoying as a good example”. Thanks John! I’ll be soon moving to western NC, so probably not an issue for me, but might be something those in far North or Canada might want to consider.

          • John Malcom

            Member
            March 1, 2022 at 10:52 am

            Good point! Perhpas a heater as they are pretty common. Us Floridia wimps are not sensitive to such things.

            Congrats on your pending move. There is a lot of snow in NC too!

            • Lou Verner

              Member
              March 1, 2022 at 10:59 am

              Snow occasionally yes, but mainly in higher elevations (I’ll be at 2200’) and both snow and cold usually don’t last more than a couple days at most, unlike northern tier/CAN.

  • Dean Carson

    Member
    May 9, 2022 at 8:20 pm

    I have a Chevy Bolt in Alaska. The temperature definitely makes a large impact. With my car cold-soaked from parking at work for 9 hours, at13F the onboard display told me that 68% of the energy went to driving and accessories, 23% to climate settings (set at 66F, with seat and steering wheel heating) and 9 percent for battery conditioning. This resulted in 2.3 miles/kw. At -26F it indicated 55% for driving, 43% for climate settings and 13% for battery conditioning. The vehicle had been plugged in while at work, so it battery conditioning and initial interior heating were supplied by the grid. The -26F scenario resulted in 1.9 miles/kw. My normal efficiency is around 4 mile/kw. It should be noted that regenerative braking does not work at low temperatures; I am not sure of the reason for that.

    • Joshua Rosen

      Member
      May 10, 2022 at 6:16 am

      Regenerative braking doesn’t work when the battery is cold because batteries don’t charge well when they are cold, there is no place to dump the current. I precondition my Tesla in the winter which warms the battery and allows regen to work immediately, if I don’t do that then it won’t work for a while until the battery heats up.

      This brings up another issue, I hope they don’t forget to provide a way to precondition the battery before heading to a CCS charger. Tesla’s do this automatically but surprisingly a number of the new CCS cars lack this capability. All that’s needed is a virtual button to precondition the battery, doing it automatically would be nice but a button will be sufficient.

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