Battery pack selection ?

Front Page Community Aptera Discussions Battery pack selection ?

Front Page Community Aptera Discussions Battery pack selection ?

  • Battery pack selection ?

  • Daniel Crotty

    Member
    August 21, 2021 at 4:27 pm

    I currently selected the 400mi battery. It raised a few questions and this may serve as a place for people to reply and ask.

    For me, I only put about 4k a year on a car so my average daily is vert low. My “long trip” to visit family a couple of times is about 375 mile, much in interstate mountains.

    1: I think I saw something similar to this “does not charge while driving”. I think that was probably intended to mean it doesn’t use the solar to run the car. It makes no sense to me why it would not charge while driving. So my 400 should be upped to 400+ up to 40, for a fully solarized version, on a sunny day. Right or wrong?

    2: If you Rarely take those long drives. Lets say 150 or less. Is there any advantage to to buying the 400mi package instead of 250mi. Here I am wondering about thing such as :

    “Never let your batter fully discharge” or

    “Batteries last longer if you don’t regularly discharge them below 50%” or

    “Buy the smallest. You will never get your $$ back. Consider the extra weight for what you do not use.” or

    “Battery technology will be better (so can you up from a 250 later easily or are you pretty much stuck with what you bought so buy a size you may need some day so an upgrade will go in)” or

    “Remember, average Winter mileage estimates will be diminished by ??%”

    OK… that is the start. Let’s see what people have to say.

  • Dennis McCall McCall

    Member
    August 21, 2021 at 4:47 pm

    I’m not going to weigh in on the range issue, everyone has their ideas on what’s best, and I’ll do what I feel is best for me. However, as I recall, the solar panels are supposed to charge at all times. (At least when they’re getting solar radiation.) The only exception being when the car is being charged with a D/C Charger.

  • Harry Parker Parker

    Moderator
    August 21, 2021 at 7:54 pm

    Here are some factors to consider:

    1. The mileage is an estimate based on the US standard combined city and highway driving cycle of the EPA. It’s top speed is something like 70 mph and its average speed is much less, something like 47 mph. (Don’t quote me because I don’t have the numbers at hand.) So . . .

    2. Your mileage may vary. ๐Ÿคจ In particular,

    3. Your high speed mileage WILL be less.

    4. Your uphill mileage will be less. (And downhill will be more. ๐Ÿ™‚)

    5. Your mileage with the heat on will be less.

    6. Your mileage with the AC on will be less.

    7. Your mileage in rain and snow and headwinds will be less.

    On the other hand, driving with a tailwind and your stop & go city driving and backroad driving on a nice cool day will be MORE. ๐Ÿ™‚

    8. You won’t want to go to 0% charge so subtract at least 5 or 10% to your distance between charges for that as well.

    9. That “40 (or 46) miles per day” from the sun is in OPTIMUM conditions: Summer Sun on a dry cool day. See the solar calculator for YOUR particular average summer and winter day in YOUR location. Here in NJ I’ll be lucky to get 3/4th of that.

    The really good news as far as I’m concerned is that Tesla recently announced they were opening their Supercharging network to all brands of EVs, starting next year. That means you’ll have access to the world’s largest network of high speed chargers wherever you go.



  • George Hughes

    Member
    August 22, 2021 at 12:13 am

    I too selected the 400 mile ~40kw battery package. I’ve got an EVSE so I could get by easily with the smaller battery.

    First, I’m retired and there are a lot of roads I’ve never explored. I want a car that will let me listen to an audio book in one trip. The 400-mile Aptera is good for a full day trip lasting at least 10 hours on the backwoods roads. I figure most of my trips will be more modest – 150 mile round trip but I don’t want to worry about it.

    But rather than get confused by the ‘mileage’ potential of the Aptera, consider that in today’s market a 40kw battery is on the low side. My Spark EV had about a 22kw battery and it’s EPA was 82 miles. That implies that 40kw would move a small EV 164 miles on the EPA cycle. Aptera’s 400 miles range comes more from the efficiency of Aptera than it does buying some massive battery pack.

    People who are really off-grid and need the 100kw battery for V2H is one reasonable use. Another is when the Aptera has V2V charging and, because of its operating efficiency, it is the vehicle recommended for the first call for road service at service stations everywhere.

    That said, I don’t think it will be three months after Aptera hits the streets you’ll see the first youtube of a guy swapping a 40kw and 25kw battery pack. A guy with a 25kw wanting a 40 or 60 kw, will advertise for a battery swap, “My 25kw batt pack + $1000 for your 40kw Aptera pack.

    My concern suggesting a robust trade in battery packs is based on the notion conjured by Nathan Armstrong who said the Aptera can be taken apart with something like seven hand tools in two hours. If in finalizing the BMS, they need a way to easily connect the BMS to the various kw/chemistry configurations with a download, plug in chip or with some switches. Bottom line you want the labor and renewed configuration in any battery swap to be less than 2-hours – at current rates about $150 for labor.

    • Steve L

      Member
      August 23, 2021 at 11:42 am

      can you link the video where he said the Aptera can be taken apart in a few hours with just hand tools? That would be awesome!

      • Daniel Crotty

        Member
        August 23, 2021 at 1:47 pm

        Steve, I do seem to recall them saying that, but wont swear to it. I think this was in one of the Webinars with Chris/Steve. Those were hour long things, so I’m not going to go looking for it. This is the closest thing I found Giving You the Right to Repair – YouTube , but not what your looking for.

        I definitely recall some portion where they said the Right to repair things, like No special tools required.

        Someone else may have a better memory. And/or, maybe someone can cut that part and put it into a YouTube that can be found on a search. This would be a thing for ppl trying to get views to their Aptera related YouTube page.

        It would make a good topic for a short Webinar or video (Hey Aptera)

  • Joshua Rosen

    Member
    August 22, 2021 at 8:37 am

    For someone who only does one road trip a year 400 miles will be plenty. 400 EPA miles will translate into about 300 miles of real world driving. For trips around your metropolitan area and even for trips to nearby cities you’ll be able to do them with no charging. As an example we went to Portland Maine from Massachusetts for dinner yesterday. I have a Model 3, I charged it to 90% before leaving and we did the 233 mile trip without charging, I got home with 13% in the battery. When new my Model 3 had 310 miles of range, as far as I can tell it’s 293 now, so a 400 mile car would have zero problem with a trip like that. For your 375 trip you’ll have to charge. If I were you I’d look at a map of the chargers along your route. Aptera hasn’t given a final determination of which standard they will use, they’ve teased a Tesla plug and that would be fantastic if that’s the way they go but I’d give it a 90% chance that they will use CCS. So look at the CCS chargers along your route, you’ll only need one but it should be a reliable so Electrify America is preferred because they have multiple chargers at each location, only half as many as Tesla but still more than one which is the case for most CCS locations at the moment. If there are CCS chargers along your route then the 400 mile version will be fine. If not order the 600 mile version, it will do that trip without the need for fast charging.

  • John Malcom

    Member
    August 22, 2021 at 11:54 am

    The EPA does not test every EV to certify their battery range. The manufacturer submits their own testing data. The EPA reviews that data, and makes a determination if it is sufficient or requires the EPA to test the vehicles based on their procedure and criteria. If the EPA is comfortable with the data summitted, they certify the battery range based on the manufacturer submitted data.

    I suspect that since Aptera is a startup (New in the market with no history) that the EPA will test the Aptera. Of course, for the testing to be both valid (returning an accurate result) and reliable Consistently returning the same result under the same testing conditions) the variance in batteries of the same KW range has to be small. This would not be the case if batteries of the same KW rating could be, from time to time, composed of different battery chemistries. (Consistent within the battery pack by maybe different between battery packs of the same rating)

    If Aptera uses different chemistries in battery assemblies of the same KW rating, even though architecturally appealing, and beneficial from the procurement perspective, It may be an issue with the EPA certifying mileage based on either Aptera summitted data or EPA testing.

    Probably moot at this point as we have no actual testing data based on a rigorous DOE (Design Of Experiments) from a close to production vehicle.

    Hopefully, we can get more information from the upcoming webinar on batteries mentioned by Sarah in her August update

  • kerbe2705

    Member
    August 22, 2021 at 11:05 pm

    In perfect, cloudless weather conditions with a full-solar Aptera sitting in direct sunlight over the course of an 8-hour day, the vehicle will store 4 kWh in its battery (unless some of that solar power is drawn-off to run the flow-through ventilation system). If the vehicle uses 1 kWh to travel 10 miles, that’s the “40 miles of solar range”.

    A FWD Aptera will have two 50 kW motors – the equivalent of one 100 kW motor. I found some figures from an EV with a 64 kW motor: When accelerating from a full stop, the motor draws 50+ kW from the battery. Traveling at 70 mph on a flat highway in clear weather with no considerable wind it draws a continuous 15-20 kW. So, even though an Aptera’s solar cells will to generate power in the presence of light, they will not generate enough power to seriously affect the vehicle’s performance or range while it is being driven.

    Another thing to consider is that all we really know about range at speed comes from vehicles that are not nearly so light and aerodynamic as Aptera: CTO Nathan has said that the aero benefit kicks-in at speeds above 45 mph – so, for all we know, Apteras may not see a significant difference in range between city and highway driving. The big difference – with all current EVs – is that highway driving (using CC or ACC) involves very little regeneration while stop-and-go city driving reaps the benefit thereof.

  • Robert Klasson

    Member
    August 23, 2021 at 2:05 am

    Well, 15-20 kW in another EV would translate to 6-8 kW for the Aptera. Full solar at 700 W would translate into a 10% range increase in optimum conditions.

    Efficient aerodynamics helps most at high speeds because that’s where the aerodynamic drag is the dominating force. The aerodynamic drag probably decrease just as much at low speeds, but at low speed, other forces are a larger part of the total, so aerodynamic drag is less of an issue.

    I wouldn’t be surprised if someone light footed and good at hypermiling would get 1000 miles of range out of a 400 mile variant, even without solar.

    • Lee Janes

      Member
      August 23, 2021 at 7:51 am

      Robert, 1,000 from 400 that’s extremely optimistic but food for thought.

    • Harry Parker Parker

      Moderator
      August 23, 2021 at 10:20 am

      Tesla fans have managed to drive a Tesla almost twice as far as its EPA rating using hypermiling techniques. See

      https://futurism.com/tesla-drivers-in-italy-just-broke-the-ev-long-distance-driving-record-on-a-single-charge

      Getting beyond 2X times a car’s rating would be quite a notable feat!

    • Joshua Rosen

      Member
      August 23, 2021 at 2:20 pm

      There is no realistic circumstance where the 400 mile version will go 1000 miles. The amount that you’ll be able to exceed the EPA range on Aptera is anyone’s guess right now since they don’t have final units and they haven’t done the EPA tests. There are two sets of EPA tests, 2 cycle and 5 cycle. Tesla does the 5 cycle and everyone else does the 2 cycle. The 5 cycle is more realistic in that it covers things like temperature ranges. The two cycle test tends to be more pessimistic because there is a big fudge factor subtracted from the range to compensate for the tests limited coverage. Manufacturers may also choose to lower their EPA numbers if they want. The two extremes in the EPA test world are Tesla and Porsche. Tesla has left absolutely nothing on the table so almost all 70MPH range tests get less than the EPA number. Porsche has managed to sandbag the tests in some way so that almost all independent 70MPH range tests has them far exceeding their reported range. Porsche wants to under promise and over deliver which is why they do this. Range is not what Porsche is selling, it’s race track performance, so they can afford to under report their range. Tesla makes range one of the key features of their cars which is why they push the EPA range tests to their limits. Aptera is all about range so my guess is that they will be closer to Tesla in the way they report range and certainly won’t sand bag the results like Porsche.

      Realistically how much better can you do then the EPA range if you have a very light foot. I have about has light a foot as you can have. Most of my driving is road trips because I don’t commute, those trips tend to be half highway and half back road. I have a 2019 AWD Model 3 which has an EPA of about 234Wh/Mile. My life time is 235Wh/Mile and 227Wh/Mile for the last 7200 miles. On perfect days and all back road I can get 200Wh/Mile. My expectation for Aptera is that if they say it’s 100Wh/Mile I’ll be able to get that but not a lot more.

    • Robert Klasson

      Member
      August 24, 2021 at 12:28 am

      To get 1000 miles out of a 400 mile battery, you’d probably have to go sub-30 mph at all times, which would mean a travel time of 35 h or more. That means you would have to shut down all non-essential systems or just the idle power draw would probably empty the battery. It would also be unrealistic to keep the vehicle out of the sun for so long, since it would have to be done in reasonably good weather to be able to go without climate control.

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