Aptera efficiencyPosted by Tom on January 18, 2022 at 3:57 pm
A commonly cited “figure of merit” for EVs is the miles per gallon equivalent (MPG-e) which serves as a useful comparison between EVs and the ages-old mpg rating for ICE vehicles. The EPA provides nominal energy costs (gasoline and electricity) for performing this comparison. Typical MPG-e values for currently available EVs range from ~60 to ~140. (See this link for additional information.)
The MPG-e for the Aptera is ~337 (!), using the EPA nominal energy costs and Aptera’s nominal 100 Wh/mile efficiency.
But it is more useful to use your own energy costs (local gasoline price at the pump and electrical cost, $/kWh, from your utility bill) to really see the efficiency improvement between the Aptera and your current vehicle.
Here’s the calculation:
- Local gasoline cost (GP) = 3.499 $/gallon (our current “best” local cost; get your value from the fuel pump at your gas station)
- Local electricity cost (EC) = 0.0738 $/kWh (our current cost; get your value from your utility bill)
- Aptera Efficiency (AE) = 100 Wh/mile
- MPG-e = (GP/EC) x (1000/AE)
For us, the Aptera would have an MPG-e of 474. We have the added advantage that we have domestic solar panels so our effective local electricity cost is about 0.0329 $/kWh. With this, the EPG-e for our Aptera would be a whopping 1,064! And neither of these even include the additional miles we’ll get when the Aptera is in the sun!
For comparison, our 2018 Subaru Outback gets ~23 mpg.
What would your MPG-e be?
- 75 Replies
- MemberJanuary 18, 2022 at 4:37 pm
Impressive! A good calculation to make for marketing when production vehicles are in the marketplace competing with the plethora of EVs co.ing out in the next two years
- MemberJanuary 18, 2022 at 4:39 pm
I have ordered the lightest Aptera (250 mile range) with maximum solar, plus I have a few solar panels I have collected over the years which I will mount on my house next to where I will park the Aptera, and with an inverter, plug in to the 110 volt charging port. I don’t expect to ever plug into the grid unless I go for a long trip. So using your formula:3.50/0.00×1000/100= infinite MPGe
Dividing by zero is tough on a calculator but Hey, when your power comes from the sun you get “free energy” once the car in paid for. Excuse me, once the auto-cycle is paid for. Yeah Aptera!
- MemberJanuary 18, 2022 at 4:41 pm
Where do you live that your only paying 7.38 cents/KWh? I’m paying over 25 cents/KWh in Massachusetts. My generation charge is 11.4 cents, dropping next month to 10.5 cents because my town negotiated a rate. The overhead for my electricity is 14 cents, i.e. the delivery charge plus taxes and fees.
MPGe is a silly metric that’s useful to people who don’t own an EV yet but once you are in the EV world Miles/KWh is the better way to express it.
The CO2e number is also interesting. Here is a tool that will tell you how clean the car will be in your zip code. Aptera isn’t on it but if you use the 2021 Tesla Model 3 AWD which uses 250Wh/mile you can get the Aptera number by multiplying the Tesla number by 2.5. For example in my Zip code the 2021 Model 3 AWD is equivalent to a 155MPG car that translates into 387 MPG for the Aptera.
- MemberJanuary 19, 2022 at 9:25 am
So many different ways of calculating energy use. I like to use watt hours per mile. Seems easier to me when comparing vehicles, seems like a little finer detail. My Solectria Force uses 190 Wh/mi so when I see these newer cars using 200-350 Wh/mi I know it’s not time to trade mine in yet.
- MemberApril 26, 2022 at 9:21 am
Do we know when there will be official numbers on the impact the AWD and Off Road Package will have on range? I’ve modified my preorder a couple of times now but I’m still very unsure what to go with. I now have all the solar panels, in a 400kw package. I live in Northern PA so we get snow here in the winter, and I am in a very rural area with the occasional dirt-driveway, and regular pothole-litered roads. I feel I should go with the AWD and ORP, but if that’s going to kill the efficiency to the point where I regularly have to charge it I’d rather do without and just drive my truck on a days with snow or trips into the back country. Does anyone have any thoughts or knowledge here? I’ve been digging through discussion posts and it seems like I’m not the only one confused on this point.
- MemberApril 26, 2022 at 9:40 am
As of right now, there isnt a lot of clarity on what the ORP is. It seems to primarily include wheel pants with greater clearance. They will impact efficiency but propbably not too significantly. If the tires were changed, that might be a more significant concern for efficiency. If it were me, i would definitely get the 3 motor configuration. I would probably also get the standard wheel pants. Worst case scenario, you may just need to remove the wheel pants if the snow is too deep.
- ModeratorApril 26, 2022 at 9:55 am
Yes… many replies in threads and the FAQ spreadsheet
I am personally planning on NMT 10% loss on the AWD and hope the ORP ends up just to be a change out of the covers for about two additional inches of GC, so minimal range impact
My Off Road is nothing more than primitive roads to get to birding/ hiking start points.
Aptera can be AWD but not all terrain trekking.
Everyone has their own needs
I plan cross country/ long treks. So 60 kWh is my plan and while national EV charging is still not where I like it!
For battery health… I plan to never exceed 80 % charge unless a stretch requires the safety of occasional 100% ….until the Aptera manual suggests something different
Surely 40 kWh will be popular for most!
My personal early notions
- MemberApril 26, 2022 at 8:35 pm
It would be really handy if the “off-road” wheel pants (assuming they are just removable pieces) fit inside the drop storage inside the trunk. Then you wouldn’t need to leave them rattling around somewhere while you’re bumping around dirt roads.
- MemberMay 20, 2022 at 1:29 pm
If Aptera can be tuned to be driven with single rear wheel in most of the road conditions, I would argue AWD may be able to achieve even longer range than FWD…
- MemberMay 20, 2022 at 1:55 pm
Aptera uses three permanent magnet motors, you can’t disengage permanent magnet motors without a clutch and that adds complexity and reduces efficiency. Tesla uses one induction motor and one permanent magnet motor, the induction motor is only used when then need extra power or they need 4WD, normally they just drive the permanent magnet motor.
- MemberMay 20, 2022 at 8:06 pm
Here’s a fascinating video published today (May 20, 2022) by MotorMatchup:
He provides a detailed and analytical look at the 40 kWh battery pack (using data provided in Aptera’s recent Battery Update Video). He goes on to delve into the efficency of the vehicle as a whole, using the modeling techniques used for his MotorMatchup EV comparison tool (very fun to play with!).
All in all, he has very positive things to say and share regarding the Aptera. He even provides a calculation that the Aptera could (there are caveats!) motor along at 18 mph using just the 700 W from its solar panels alone.
- MemberMay 20, 2022 at 8:45 pm
He did a solid analysis and presented it extremely well.
We don’t have final statistics so details like rolling resistance, weight, frontal area, aux drain and cells are educated guesses or unconfirmed. He does make the assumption that Aptera will still have 0.13 Cd which seems unlikely given the unfortunate need for mirrors (thanks NHTSA). He is also assuming a ~25 sq ft of frontal area which is comparable to a model S; 22-23 is more likely based on the STL file sent to ambassadors when viewed to scale (I previously assumed 20 myself but believe it was low). I updated my calculations based on this and split the difference on some other details and it seems to model very plausibly at all scales except the base 250 mile since 4 modules similar to those described overperforms by ~20 miles of range.
- MemberJuly 29, 2022 at 6:46 pm
I can’t get the concept to settle in my head. I expressed fuel efficiency all my adult life as miles per gallon (distance from a certain amount of fuel). Now the concept includes a factor of time? Now it’s amount of energy AND time AND distance? It doesn’t make sense to me. I only used time when discussing speed. Why isn’t miles per kilowatt or watt used? What does an hour have to do with it?
- MemberJuly 29, 2022 at 6:59 pm
I agree but maybe it should be the number of kilowatts used per 100 miles. This is similar to how “mileage” is determined in metric countries: liters per 100 kilometers.
- MemberJuly 29, 2022 at 11:17 pm
For me to understand this may be a matter of osmosis. I feel like I have a slippery grip on the front of it, but maybe not all of it. I may lose what little grasp of it I have, but I have this conversation to remind me where I got to.
An Aptera will be my first electric vehicle. I was so excited about it when they started the first time because AT LAST someone was putting out a viable solar-powered vehicle. I couldn’t take advantage of it then, even if they had stayed in business (divorce, digging out of debt). I have a second chance.
Thank you all very much for helping me.
- MemberJuly 30, 2022 at 2:56 am
For me whenever I can’t grasp how a certain technology works I imagine that it’s running on magic. The best way I associate electric cars to gas cars is cost to refill/recharge and how far that takes me.
My gas car goes 350 miles on a $90 refill so .25 per mile
My Tesla goes 230 miles and costs $32 to recharge so .13 per mile
Aptera will go infinity miles and cost $0 to recharge. Good deal
- MemberMay 23, 2023 at 3:56 pm
As long as you drive no more than 40 miles a day and have full solar exposure.
- MemberJuly 30, 2022 at 8:19 am
This explanation from Google may help (I’m learning this crap myself (MPGe))…
Kilowatt hours (kWh) are the units in which electrical power usage is primarily measured — they are what you see on your electricity bill. The reason that this unit is used to measure your usage rather than kilowatts on their own is because kWh is a measurement of absolute power consumed over time. It’ll take absolutely 1kwh to run a 100watt bulb for an hour.
EDIT: my bad… bulb for 10 hours
- This reply was modified 1 year, 1 month ago by Selvan Poothamby.
- MemberSeptember 25, 2022 at 8:12 am
At what speed is 100Wh per mile expected? How many Wh’s are expected per mile at 70mph freeway speed (assuming zero wind)? I can’t find anywhere that there’s a standard speed for testing kWh per mile of any EV. Seems like they just publish an average. If 100Wh/mi is expected at 35mph, then I suppose using pump laws (“pumping” air in this instance), where doubling the speed requires quadrupling the power would mean 70mph expects 400Wh/mi. That’ll mean a pathetic 125 miles on my 60kWh / 600 mile Aptera? Let’s hope not!!!
- MemberMarch 6, 2023 at 7:57 am
In your ICE, what speed is 30 mpg? It varies constantly, its an average.
- MemberSeptember 25, 2022 at 8:36 am
From the old Aptera FAQ spreadsheet, it’s based on “The EPA driving cycle with a max speed of 67 mph in normal conditions.”
- MemberSeptember 25, 2022 at 8:37 am
I’m not sure of the exact speed, but I believe the 100Wh/mile calculation includes highway speeds. This is all theoretical until we get actuals, but the results won’t be the same for all models due to differences in weight. I heard they calculated this on the heavier batteries (1000 mile perhaps) and mentioned they think they might beat it. I’m not holding my breath on these statements until the official Delta tests are complete, but with the Cd nearly half of Tesla and 1 less wheel, you’d expect the power required to be less than half as well. So if Tesla 3 is drawing 242 Wh/Mile (average city and highway) with a 54KWh battery, the claims don’t seem crazy at all. The real question I have is whether they will actually achieve the Cd of 0.13 with the modifications they’ve needed to make. I suspect they will not because of the side mirrors, etc, but I would expect them to be in the ballpark on their ranges and Wh/mile calcs at highway speeds.
- MemberSeptember 25, 2022 at 12:44 pm
This is my calculations with some estimates on some specs for the 400 mile Aptera. You can see from this how range would degrade with speed as compared to a model 3.
Note: Many details of the specs are estimates and the aux load / road friction is a major factor in low speed range.
- MemberSeptember 25, 2022 at 3:59 pm
Curtis, much thanks!
It appears that 400 miles would be achieved going 70mph for the introductory version. Please verify if I read wrong. Also I would expect similar results minus added wait for the rest of the battery packs offered?
- MemberSeptember 25, 2022 at 10:50 pm
I have estimated for all battery sizes but given we don’t know what cells like 2665 or 4680 they might use. The constants might be wrong but your welcome to change them (copy the sheet). I feel these numbers should be in the ballpark. At 70 mph the 400 mile would be 333 miles (by my estimates) but that includes many assumptions that could be either high or low regarding drag, rolling coefficient, weight, aux load etc. The 400 mile battery is relatively understood given details to date but others are extrapolations.
Personally I’ll be purchasing with awd and offroad options and would be happy with 200 miles of real world winter range.
- MemberNovember 2, 2022 at 8:00 am
From another thread someone was contemplating driving 55 to maximize range. Out west the speed limit is often 80 mph. I don’t advocate reckless speeding, but might it actually be more efficient to drive 90 MPH for 60 minutes vs 60 mph for 90 minutes? This would save 30 minutes of AC/heat/headlights/computer etc for the same 90 mile trip.
- MemberNovember 2, 2022 at 8:11 am
When calculating MPGe, aero drag goes up at the square of speed (technically it is cubed, but because MPG includes miles in the units, it cancels out).
So purely from a drag viewpoint, and ignoring other factors, you’d use far more energy at 90 (more than double) than if you drove the same distance at 60.
The recommendation would be to drive at the slowest reasonable speed for the highway. If all other traffic is doing 90 then 55 wouldn’t be reasonable. But if there is a mix of speeds, speed match with the slower vehicles.
Below highway speeds, the aero drag is less relevant and the other factors (such as aircon) come into play.
There are online calculators you can use to experiment with the parasitic loads versus CD versus speed to calculate MPGe.
- MemberNovember 2, 2022 at 8:22 am
Aptera is not fundamentally different from other evs; it’s just lighter and more aerodynmamic. The optimal speed for range is likely a constant 15-20 mph. Slower and losses from aux load like computers, cameras, screens, and bms add up (ac or heating are huge if used). Faster and air drag causes some losses. Depending on aux load Aptera in full sun could break even at about 16mph so hard to get totally stuck running out of battery.
Feel free to play with numbers by making a copy of my calculator (note some specs are educated guesses but are all likely +- 15%)
- MemberNovember 2, 2022 at 8:48 am
The energy use per mile from AC, headlights and computer is trivial when compared to the energy to move the vehicle. Kinetic energy is 1/2MV^2, i.e. it’s goes up as a square of the velocity. The energy used by the heater is massive compared to the other parasitic energy consumers so there probably is some combination of temperature and speed where going faster saves energy.
- MemberNovember 2, 2022 at 9:06 am
I love the spreadsheet. I noticed that the variables changed from the upper calculation vs the lower calculation at 70 mph and it spits out different answers.
From your work (run time) it wouldn’t be to difficult to figure optimum speed if you knew environmental controls energy use per time at a given temperature.
I want to go the speed limit. 80 MPH here in Utah. It looks like I will be disappointed that I will not be getting the near the full range. I am surprised by the difference.
- MemberNovember 2, 2022 at 9:19 am
> “I want to go the speed limit. 80 MPH here in Utah. It looks like I will be disappointed that I will not be getting the near the full range.”
MPG and range claims are regulated by the EPA – they must be calculated using a fairly slow highway speed (albeit higher than the WLTP MPG regulations). That’s the reason that people generally don’t get the advertised range (their highway speed is higher than the EPA highway speed).
- This reply was modified 10 months, 4 weeks ago by Michael Marsden.