- MemberJanuary 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?
- 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 18, 2022 at 5:35 pm
I live in SE Washington State… fair amount of hydroelectric and wind power. Oops, my mistake — I used $0.0738 where the actual rate is $0.0739. I did not include the flat daily rate (currently $0.63 per day) or the local sales tax. No argument from me that the MPG-e number is a bit silly, particularly if you’re charging your Aptera from free sources (e.g., the vehicle itself or external solar panels). As noted by Francis Giroux above, in this situation the MPG-e → ∞.
- 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.
- MemberJanuary 19, 2022 at 2:40 pm
There’s a pretty good explanation why the MPG number is a terrible number to use for improving fuel economy
The TL/DW is that as that number gets bigger the improvement in consumption shrinks. So if you say ‘raise the fleet average by 10MPG’ as a standard vs ‘increase the 100 Miles/Gallon (or any measurement like liter as well, but this is America) I found the video interesting but I’m weird.
- 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 3:13 pm
Thanks Leonard. I just looked through the FAQ page again and still can’t find a reference to the efficiency loss of the AWD, but that sounds like a good number to go by. I’m going to stick with the full solar package, I’ve removed the ORP and I’m still on the fence on the AWD. I’m at a loss for your NMT abbreviation :-/ I feel like it should be obvious, but I can’t get it 😛
- MemberApril 26, 2022 at 10:39 pm
Len’s “NMT” means “no more than”…
You won’t find the 10% figure (range hit for AWD) in the FAQ – it was mentioned by Chris during one of the webinars given for Ambassadors.
I’m going with AWD for two reasons: We have amazingly sudden “flash flood” downpours here in the deep south that can dump 2-3″ of water on the road in front of you within a matter of minutes and, also, the occasional ice storm – but mostly because I drive from Mississippi to the Poconos every year to visit friends and family. I know what it’s like to drive the not-well-plowed Northeast Extension and to crawl over the Blue Mountain on 309 and 100 in the snow!
- 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.
- MemberApril 27, 2022 at 2:32 pm
If all 3 motors use the same power, the AWD will increase power usage by 50%. That would bring the 400 mile range battery down to 266 miles. So if this is accurate, if you want 400 miles or range, you’d need the 600 range batter for AWD.
Maybe the team have worked out a way to improve that efficiency, but considering the improvement the AWD upgrade makes in acceleration. I wouldn’t expect it to be too far off from this worst case.
We’ll see. Hopefully my ignorance is on full display here.
- MemberApril 27, 2022 at 2:58 pm
I don’t see how the two front motors will continue to work as hard if they have another motor pushing them from behind. In an apples to apples acceleration and load comparison, you would definitely expect a loss in efficiency, but not nearly as much as that of an entire motor. All motors will work together, lessening the strain on any single motor, but increasing somewhat the total power used across all 3.
- MemberApril 27, 2022 at 3:22 pm
The AWD can get enough power from the ~25KW version to fully power all 3 motors but when maintaining a constant speed you arent using a tiny fraction of even 2 motors full power. Because the motors are permanent magnet and cant be shut off their is a efficiency hit but it isn’t 33%. They have said it will be around 10%. This incidentally is around the hit of AWD vs FWD in models with both options.
So lets say we have the 400 mile version, lose 40 miles from AWD, another 40 miles from offroad wheel pants, 50 from driving 72 mph instead of 60 mph, and 20-50 for heat/cooling/stereo. Now you are looking at 220-250 miles of range rather than 400. Still reasonable but these real world factors are why I (and I suspect many) chose the 400 mile version instead of the base.
- MemberApril 27, 2022 at 3:29 pm
The power used is the power required to perform the task at hand. If you are cruising along on the highway you have to overcome the resistance of the air and the rolling resistance of the car. The third motor has zero impact on the aerodynamics of the car but adds a small amount of weight which will increase the rolling resistance slightly, very slightly. If the power required to do that is X then if you have two motors then each motor has to contribute X/2 and if you have three motors each has to contribute X/3. The motors in the AWD will be running slightly cooler than the motors in the FWD which means that the resistance of the windings will be slightly lower which means that the i^2R losses will also be slightly slower. When accelerating the extra weight of the third motor will increase the energy used but not nearly as much as a bigger battery or a second passenger will. The only time you will see a big increase in the instantaneous power used is if you floor the accelerator. The AWD will do 0-60 in 3.5 seconds while the RWD will do it in 5 seconds or so, to get to 60 in 3.5 seconds takes more power. However if you drive like a sane person and do 0-60 in 8 seconds the power used will be the same for either setup.
- MemberApril 27, 2022 at 3:29 pm
Well now I feel dumb. The answer was staring me in the face all this time. The two options are 100kw or 150kw(AWD). The FWD is 100kw and on a 400kw battery that will lend you a 400 mile range. The AWD is 150kw and on a 400kw battery that will lend you a 266 range as you stated. Take that a step further the solar cells charge 4kw in a day, or 40 miles gained in a day. If you have the AWD however you will only gain 26 miles in a day on that same 4kw charge. I guess that answers my question! My average daily commute isn’t all that much, but I would hate to take that big a hit on efficiency just to be able to ‘smoke’ practically any car on the road (pun intended).
- MemberApril 28, 2022 at 8:46 am
That’s not how power and capacity works…
The battery is 40 kwh – Kilowatt-hours.
The motor’s peak power is 100 or 150 kw – Kilowatts.
That doesn’t mean that’s how much power it uses all the time, that’s only when you floor it.
If you have a 40 kwh battery pack and you somehow floored it until the battery died, it would run out in .4 hours with FWD and .26 hours with AWD.
When just driving along, the FWD version will use about 10kw and the AWD version would use about 11kw to keep rolling along at highway speeds. Unless you step on it then it can go up to 100 or 150 kw for a few seconds.
The solar produces 700W or 0.7KW of power (max). In a day this produces about 4 KWH of energy because it doesn’t work at full energy all the time. If you go 10 miles for each kilowatt-hour (kwh) that’s 40 miles.
Kilowatt – KW : Power, like horsepower
Kilowatt-hour – KWH : Energy stored, like gallons of gasoline.
Running a motor at 1kw for 5 hours consumes 5 kwh. Running a motor at 3kw for 1 hour consumes 3 kwh, etc.
- MemberApril 28, 2022 at 7:18 pm
Thanks Peter, that was a great explanation. I kind of started thinking like that too right after I replied. But kept my mouth shut because I knew someone would explain it much better. (Cunningham’s law). I’m hoping that the designers/engineers will provide better estimations as we get closer to the actual production date. Perhaps even actual real-world-tested-results.
- MemberApril 29, 2022 at 7:29 am
I don’t believe there will be a 10% difference in efficiency between the FWD and the AWD, it’s likely to be about the same. The Tesla Model 3 RWD has an MPGe of 132, the AWD is 131. For city driving it’s 138 vs 134 but the AWD M3 is 600lbs heavier than the RWD. Tesla puts a smaller battery into the RWD which accounts for most of the weight difference. Aptera keeps the battery size independent of the number of motors so the difference between AWD and RWD is likely to only be 50-100lbs. Battery size will make the big difference in city driving efficiency for Aptera because there is such a wide range of battery sizes. On the highway weight is much less important as long as you are driving at a steady speed, for the Model 3 both the RWD and the AWD have an MPGe of 126.
My guess is that if they’ve said AWD is 10% worse than RWD that’s just to cover their asses, it’s better to under promise and over deliver. When the final numbers are measured I’d lay odds that the efficiency hit for AWD will be very small.
- 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.
- MemberMay 20, 2022 at 9:43 pm
Great spreadsheet Curtis. It really gives a lot of useful information. The only thing I think that is a little off is the cost per cell. I can’t find good info on the cost per cell of this type but I can for cost of NMC cells per KW and it is about 110 dollars at the cell level for 2021 and could raise to 135 at the cell level according to this Bloomberg article. https://about.bnef.com/blog/battery-pack-prices-fall-to-an-average-of-132-kwh-but-rising-commodity-prices-start-to-bite/#:~:text=We%20estimate%20that%20on%20average,closing%20in%20on%20%24110%2FkWh.https://about.bnef.com/blog/battery-pack-prices-fall-to-an-average-of-132-kwh-but-rising-commodity-prices-start-to-bite/#:~:text=We%20estimate%20that%20on%20average,closing%20in%20on%20%24110%2FkWh.
That puts the cell cost at between 5000 and 6000 dollars for the 40 kw pack.
- MemberMay 21, 2022 at 2:16 pm
Recent metal prices have likely brought prices up. My method was to look at the retail 2170 cell market and take an additional 10% off their price for 1000+ cells. I also used a inr21700-50e which is cheaper and more available; the inr21700-50g cells are hard to find and expensive. It is possible Aptera will be able to get cells cheaper but probably not the 35% less that you are suggesting. I also listed a alternative cheaper cell; Samsung are the industry gold standard but as a result are more expensive. If they can get the cells for cheaper that is good because the 1000 mile version will need a absolutely nuts amount of cells (likely 3x that of the current 400 mile pack). Battery cells are a expensive high demand commodity and Aptera will likely need to pay a premium over established companies as a result of lower volumes.
- MemberMay 21, 2022 at 12:05 pm
Great info indeed! Thanks!
One question: given the airplane-like shape of Aptera, whether a significant lift would be generated at high speed, which could lower the load and rolling resistance?
- MemberMay 21, 2022 at 12:20 pm
QF, the design is actually set up to provide downforce at speed to keep the vehicle stable, however, as I recall it is balanced to end up with only the needed amount of pressure to keep the load and rolling resistance low.
- 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 7:18 pm
The trouble is that a watt is a unit of power (energy per unit time, or Joules per second). For some reason, we are multiplying it by time (kwh) and using it as a unit of energy (instead of just using Joules). Perhaps ‘kwh’ is convenient for some reason one of our fellow Apterans can muster.
- MemberJuly 29, 2022 at 8:04 pm
Electricity is sold by the KWh, look at your electric bill. Gas is sold by the gallon, a gallon of gasoline is equivalent to 33.7 KWh.
If you are interested in your cost per mile then want to see the energy efficiency expressed as KWh per mile, so for example if you are paying 25 cents per KWh then the Aptera, which uses 100Wh/mile, will cost you 2.5 cents per mile. If you are interested in range then you want to see the reciprocal, i.e. miles per KWh. The Aptera is 10 miles per KWh so you can travel 400 miles with a 40KWh battery.
- This reply was modified 4 months ago by Joshua Rosen.
- MemberJuly 29, 2022 at 8:11 pm
I pay 7.9 cents for the first 450KWh, then 12.9 cents for anything over, but that’s not going to be relevant since I will use the sun-charge most days. What I don’t get is why does anyone put “hour” in the label? It’s not a function of time, is it?
- MemberJuly 29, 2022 at 8:28 pm
A kilowatt is an instantaneous measurement (technically, a watt is one joule per second and a kilowatt second (vs hour) would be one joule per second for one second (kind of like acceleration). The “kilowatt-hour” would equate to the total energy the system now contains rather than the rate of energy being put in. Kilowatt=rate; kilowatt-hour=total elapsed.
Another way of thinking about it, if you’re filling a bathtub, your water flow rate is in liters per second (kilowatts), but you want to figure out how much water is in there, you need to know the total number of seconds (elapsed time) and the flow rate (kilowatts) to calculate the liquid volume.
- This reply was modified 4 months ago by Jared Cormier. Reason: stupid typo
- ModeratorJuly 29, 2022 at 8:45 pm
From basic Physics: Energy = Power times Time. Electrical power is measured in watts.
Electrical Energy can thus measured by multiplying power (in watts or kilowatts) times time (in seconds or hours). Why that unit? History, I guess.
Here’s an example that might help. Say you switch on a 100 watt (old fashioned incandescent) lightbulb. 100 watts is a measure that determines how much electrical power your light will draw and how bright the light it will be. Leaving your light on for one hour requires 100 watt-hours (= 0.1 KWH) of energy, (enough to drive the Aptera 1 mile). If you had a 200 watt light bulb, it would demand twice the power. However if you left it on for only half an hour, it would use the same 100 watt-hours.
If you drive an Aptera at 50 miles per hour, it will go 50 miles in an hour, using about 5 KWH in that hour.
- 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
- MemberJuly 30, 2022 at 4:58 am
Lane, you misremember slightly, the Aptera from the first years (Before 2012) was not a solar vehicle, although it did have a minimal amount of solar panels on the roof to run a parked ventilation system.
- 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 4 months ago by Sam Adams.
- MemberJuly 30, 2022 at 9:33 am
If you prefer there is another unit of energy, the joule. A joule = watt second so a KWh is 360KJ. Electric companies don’t bill in joules they bill in KWh so the KWh is the most convenient unit to use because you can translate it into cost and dollars and cents are the units that people are most interested in.
- MemberJuly 30, 2022 at 9:44 am
My conclusion: I’m going to try to just leave the “h” (hour) out of my thoughts of watts. I know electrons are moving and I don’t need to use badly named terminology to tell me so. It goes against the grain to not read the “h” but it’s not my fault all tech terms aren’t perfect. It’ll be just watts and kilowatts.
- MemberJuly 30, 2022 at 9:49 am
All you have to do is recognize that the ‘h’ is there merely to denote there’s a period of time involved. Like a month in a utility bill.
- MemberJuly 31, 2022 at 6:36 pm
Outside of a few keyboard warriors on various forums, nobody is going to care in real life if you leave the ‘hour’ part off.
My car has a 100KW battery pack
I had to charge my car with 50KW today
I’ll use 25KW driving those 250 miles
They all are technically incorrect, but explain what you mean exactly.
- 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!!!