MemberApril 10, 2022 at 12:58 pm
<font size=”4″>3000 Mile Trip Across
USA Without Plugging In</font>
Given unlimited time (months) anybody
can do it, but to shorten the time required you have to optimize everything. My goal is less than a month. How is that possible if
the best solar exposure with a full solar package can only give you
around 40 miles per day average?
Well there are many things that can be
optimized. First of all that 40 miles per day is an average day in
Southern California. I assume that means averaging every day of the
year. Considering that there are 700 watts of solar panels on the
car and 12 hours of average sunlight per day would make it possible
to get a maximum of 700×12=8400 watt hours per day. And Aptera
advertises 100 watt hours per mile at 60 mph. To maximize the total
solar energy collected per day you want to do a few things:
1. increase number of hours per
day the sun shines on the car.
2. orient the panels on the car to
the best angle towards the sun.
3. concentrate the suns rays onto the
4. Keep the panels from overheating
(cool panels produce better).
For # 1 you can pick the season with
the most sunshine, around Summer Solstice (June 21). If you expect
the trip to take a month, then start 15 days before solstice, So
start the trip in early June.
For #2 Spend all day adjusting your car
position so you are facing as many panels toward the sun at best
angle as possible. Position the car to face directly at the sun and
open the hatch so the sunshine hits the panels there at the best
For #3 Use large mirrors to redirect
sun light from sides and rear of the car to the panels on the car.
My plan is to carry four to six panels that will fit inside the hatch
that are a light weight wooden frame covered with Mylar Blanket
material (2 mil thick aluminum coated Mylar).
For #4 Carry enough water to spray,
with a hand spray bottle, enough water droplets onto the panels so
the evaporation of this water will cool the panels.
#5 would be “cheating so I won’t do
it but I’ll tell you that I could carry numerous 100 watt solar
panels and set them up during each solar collection period to
increase collection, but technically that could be considered
“plugging in.” What I would like to see is solar cells attached
to the doors, because when the doors are left open they are both
facing the sun when you have the car oriented at described above.
So that’s how you collect maximum solar
energy and put it into the battery. This could be 16 hours of
sunlight (in my New York State location) plus a couple hours of
twilight, not all at maximum efficiency but certainly more than the 6
hours of average sun exposure when leaving the car in a parking lot,
locked up all day. Let’s estimate we could squeeze out 12 hours of
good angles for 8400 watt hours per day plus whatever we can get
reflected from our “mirror panels” which I would estimate as only
50% effective at redirecting the energy from the sun to the panels.
With all working as expected we should be able to get 12 kwh of charge
Now, lets talk about efficient driving,
which we can’t do while collecting solar. I plan on driving during
twilight and low sun angle hours or during cloudy period when
collecting is less than effective, or at night. Charts have been
posted that show that if the energy consumption at 60 mph is 100 watt
hours per mile, then traveling at the most efficient speed (around 30
mph) is more than twice as efficient. And that is not even including
my porpoising driving technique. Let me explain porpoising. If you
draw a graph of speed versus time of any car being driven, you’ll
see a graph like the first picture below:
Where the graph goes up, the car is
accelerating, the wavy line on top is some slight deceleration and
acceleration during cruise on a windy road, and the dive at the right
end of the chart is braking at the destination. If you use mild
porpoising technique the graph will look something like the second picture below:
You speed would be less overall which
is more efficient, the acceleration would be fairly rapid because
even an ICE car is most efficient at hard acceleration, electric wheel
motor car is slightly best under hard acceleration, but the main
reason to accelerate fairly hard is to shorten the total time of
acceleration and lengthen the time of coasting, which is when the
graph is going down slowly. Notice there is NO steep declining of
the graph which would indicate braking. Notice that the graph
follows the position of a porpoise traveling through the water, hence
the term porpoising.
Extreme porpoising would look more like
the third picture below:
Why is this better than just cruising
at 30 mph? According to the charts put out by Elaphe Motors video,
cruising at only 100 Newton meters of torque is less efficient that
accelerating at 800 Newton meters of torque. But how efficient is
the electric motor when no electricity is being used? Well if no
regenerative braking is going on (open circuit in the motor/battery
loop) the motor should be 100% efficient except for friction caused
by seals and lubrication. We already know that the Aptera is
aerodynamically efficient and rolling resistance is minimized, so the
coasting phase of porpoising should take a long time and cover a long
I know when I competed in the Tour de
Sol mileage competition with my Saturn SL1 and achieved 100 mile per
gallon, I was porpoising by accelerating from 30 mph to 60 mph in
about a quarter mile, and coasted from 60 to 30 mph in about a half a
mile. The Aptera will likely be much shorter acceleration spurts and
much longer coasting periods. In fact the program I used (Paint) to
draw the second graph above wouldn’t allow me to illustrate it like
I wanted to, which would almost look more like a saw blade. Hey good
idea, third graph figured out.
I guess that the coasting of an Aptera
from 60 mph to a full stop would cover more than a mile of travel.
But I’m not planning on accelerating all the way to 60 mph. I’m
likely to porpoise from 20 to 40 mph which would average about 30
mph, unless that speed takes too long to deplete the solar energy I
collected that day, without having to turn on the headlight and
travel in the dark.
Let’s go back to our expected solar
collection numbers and estimate how far I could travel in one day. I
estimated above that we might be able to collect 12 kwh on a long
sunny day with reflectors and proper positioning. I also estimated
that traveling at a constant speed of 30 mph should bring me twice as
far as at 60 mph, or about 20 miles per kwh, and with porpoising I
should be able to squeeze out another 30% for a total of 26 miles per
kwh. Multiply that by a good sunny day’s 12 kwh collected we are
approaching 12×26=312 miles. And If I do that at an average speed of
30 mph, it’ll take me over ten hours.
Ouch, that means I’ll have to cut down
my collection time, or drive faster, or drive with the lights on. I
wonder how much energy the headlight and tail lights take to run. If
all the optimistic estimation I have relied upon here are correct, I
could get across the country in ten days. Wow that would be better
than I expected. I was planning on a whole month (100 mile per day).
Would it be a boom to Aptera interest if I could actually garner 300
miles from the sun on a long day?
Since I have a goat farm to take care
of, I don’t see how I can actually take a month off to go solar
surfing across the country and back so maybe when I get the dream
machine I’ll just pick a great sunny day around summer solstice and
try for the 300 miles while starting with a dead battery.
- This discussion was modified 2 months, 3 weeks ago by Francis Giroux.
MemberApril 10, 2022 at 2:42 pm
I suggest Norway in late June.
MemberApril 10, 2022 at 3:58 pm
Yeah that would give me around 20 hours of sunlight. The Aptera does float. Maybe I could put my fishing electric motor on the tail and just “drive” it to Norway.
MemberApril 10, 2022 at 5:10 pm
Even driving around Norway, an amphibian would come in handy. Given the irregularity of the coastline it is possible to spend half a day driving on land just to get to the other side of the fjord.
MemberApril 10, 2022 at 2:45 pm
Francis, I didn’t read your entire comment but I’d like to help you with what I see as a first mistake. I hope you don’t mind.
If the “full solar” does, indeed, produce 700 watts at peak conditions, this is multiplied by the number of “peak sun hours” over the time period of interest (also known as “Insolation”) on a defined surface for a given location and time of year. Do not multiply it by the number of hours the sun is out. For example, San Diego, California has the following “peak sun hours per day” averages for a horizontal surface:
To obtain the energy the solar will produce over some amount of time (let’s say 5 days in May), simply multiply the peak wattage (0.7 kw in this case) by 6.42 “peak sun hours per day” then by 5 days. The answer is: 22.47 kw-hours.
Also, a note about “cooling” with water and evaporation. If you really want to do it, I highly advise you use be sure to “wash” all dust/dirt on the solar array before spraying small quantities of water. Second, be sure the water is “de-mineralized” like distilled or reverse-osmosis (RO) water. If not, when the water evaporates, there WILL be minerals “coming out of solution” and usually sticking VERY well to the top of the solar array. I sometimes build custom solar modules with essentially non-stick Teflon-like materials (ETFE or FEP) on the top and minerals still stick pretty well to them! Third, please realize that the amount of cooling from the evaporation is not significant. You would get far more heat transferred away from the solar array if you continually “flooded” the array with water rather than simply spray/evaporate/spray/evaporate etc. but be warned. It’s a lot of water!
MemberApril 10, 2022 at 3:54 pm
Thanks Alain for the tips. My calculations for the number of hours of solar collection was based on a 16 hour day and tilting the panels toward the sun so there is as close to a perpendicular exposure as possible. The hood of the Aptera is already tilted toward the sun when positioned as described, the dash and roof are not as good, and the majority of panels are on the hatch which will be open and have the best exposure of all. I may even carry a wedge block or portable ramp so I can drive the rear wheel onto it to improve the angle even more.
My water at home is Culligan softened but if I see a mineral deposit forming I’ll get a shammy and wipe it off. Spraying water mist onto the panels during collection is likely the best I would be able to do when I’m stuck out in the middle of nowhere on a cross country trip. I would not have access to running water all day, and still keep a low profile. Now if Aptera wants to sponsor the trip and enable planned stops with running water access, that would be a different story. But my goal is to show how a person alone can cross the country with no electricity in a solar electric vehicle without taking all summer to do so. Ten days would be great.
MemberApril 10, 2022 at 4:59 pm
I am excited about the challenge you are willing to take on!
I certainly would not bet against you. People who have that much enthusiasm about a challenge find a way to get it done. It mirrors Aptera and their commitment to developing the most efficient transportation in the world, a remarkable engineering and production achievement In the face of some really daunting obstacles.
It is nice to see the forum experts chime in with advice too.
ModeratorApril 10, 2022 at 4:35 pm
Francis, taking a 300W portable folding solar PV panel along for the ride would help the daily range a bit. According to Chris A. in Aptera Owners Club video recently, a direct connection into the Aptera battery pack will be included to enable owners to charge directly from standard solar panels. Apparently, the onboard solar controller has some wiggle room in capacity to allow this type of maneuver.
MemberApril 11, 2022 at 12:03 pm
Yeah but my self inflicted rules for the challenge only allow the Aptera standard full solar package for source of energy. I defined “plugging in as any wire connected to the Aptera, whether it is via the normal recharging connector or the 110 volt charging connector or any external solar panels connecting via a wire to the Aptera.
Of course for my normal operation I already have three 100 watt solar panels I bought a few years ago and an inverter, that I intend to mount to my house next to where I will normally park the Aptera and plug that in (but not during the challenge), even if Aptera doesn’t include the port to plug the panels in directly without an inverter.
MemberApril 10, 2022 at 5:15 pm
Chris floated the possibility of a 1kW array to put on top of a camping add on. If that product was made, then you could drive a couple of hundred, stop for a few days doing your favourite outdoors thing. Then go again.
MemberApril 11, 2022 at 12:37 am
This effort/feat is an inspiring use-case scenario! Congrats.
Lets assume the apocalypse has come to pass and there are no more gas stations or electric grids and you need to get from NY to LA.
Even an ICE vehicle converted to pure ethanol would be limited to the fuel the now poorly running vehicle could carry.
The plain fact is you wouldn’t penalize yourself by starting with a dead battery; you’d start with whatever battery you have. The extra-solar power camper addon is a must. And why not include a panel similar to the existing one that stretches to cover both doors in the open position while providing an expanded canopy for more solar cells.
That you could make a cross country trek without so much as a single plug in is a story because it takes extra time. I think the key to making a news story, at least in the prepper community – there are a lot of influencers on youtube in that group – is your long trip is being done as if there had been some massive catastrophe. In this imaginative apocalypse, the roads are largely intact but your adventure would include the ability of the Aptera to go off road and forge, even a small stream or river.
Possibly an even better idea would be to cast it as the Apocalypse challenge which would be a cross-country no, outside input (fuel, food or lodging) from say Seattle to St. Louis … basically the west and the great plains … and open it to folks on horseback, on camels, or in a vehicle (bicycle), motorcycle or car. Those on horseback could have pack animals and in the race, the contestant teams could hunt, fish or forage for natural food but their ability to scavenge would not include the 7-11. Because of the distances involved, roads would be allowed/used but there would be specific ‘stages’ where an off-road course provides different challenges including fording streams and other obstacles.
Who would win?
I’d be betting on Aptera.
MemberApril 11, 2022 at 12:58 pm
I may have no reason to go from New York to Los Angeles in an apocalypse, but I do have a son in San Francisco area expecting my first grandson any day now. He might be worth the trip even if the roads are empty. You were talking about other method including horseback. I already have a way to get across the country in 30 days, but would prefer to have places to eat along the way, so it might not be an apocalypse challenge.
See that yellow contraption on my profile photo? That is my human powered racing machine in which I have previously covered eight hundred miles in eight days (resting on the Sabbath). Between this one and two previous recumbent tricycles, I have traveled more than twice around the world (56,000 miles) since 2010. In a previous post in some other Aptera forum I showed that at one hundred watts of input, I cruise at 15 mph covering 15 miles with 100 watt hours, compared to Aptera at 60 mph covering one mile with 100 watt hours. According to a chart by another Aptera “owner” at 20 mph, when I am using about 200 watts (10 watt hours per mile), Aptera is using something over 30 watt hours per mile. So my cycling machine is at least three time more efficient at the same speed as the Aptera. But it only carries one person and no luggage.
MemberApril 12, 2022 at 5:02 am
If it’s true that the Aptera can travel a mile on as little as 30 Wh then a summertime drive across the US can be done in 30 days or less on its built-in solar. 700 watts x 5 hours / 30 Wh per mile = 116 miles per day. 3000 miles / 116 per day = 26 days
Math is not my long suit so correct me if I’m wrong.
MemberApril 12, 2022 at 7:34 am
Your math is correct but are you willing to travel at the same speed I can pedal (20 mph or less)? If so maybe we can do a joint trip, you drive the Aptera, I ride my pedal car, and we stick together, you can even carry the food and it can be a real apocalypse challenge.
MemberApril 12, 2022 at 8:26 am
I get to drive a Sag Wagon? Sweet!
Prevailing winds being what they are, maybe we should go LA to NYC.
- This reply was modified 2 months, 3 weeks ago by Russell Fauver.
MemberApril 12, 2022 at 8:51 am
So this would be the record slowest Cannonball run, maybe call it the Wiffle Ball run.
MemberApril 12, 2022 at 11:29 am
What is a Sag Wagon?
MemberApril 12, 2022 at 12:06 pm
Sag wagon: a support vehicle for bicycle group rides. Carries tools, snacks, water, gives rides to people who can’t finish the route under their own power. Maybe it’s not a common term anymore. It’s been 20 years since my last organized ride.
MemberApril 15, 2022 at 10:50 am
You want speed v. time on those graphs. Also, I’m going to keep saying this until Aptera changes their PDFs – 10 miles/kWh is the efficiency value for the 100kwh AWD version ONLY. The other versions DO NOT have a similar efficiency value because they are all lighter significantly.
Simulations are so good and they’ve been in beta for so long there’s no reason not to provide efficiency estimates for the other variants, and give real estimates of their pack sizes.
Could be looking at a 35% reduction in Wh/mile.
MemberApril 15, 2022 at 12:18 pm
You’re right Mark, the graphs would be shaped somewhat differently if they were speed vs distance, but to explain what porpoising is, both get the point across.
I agree with you about the 10 miles/kWh. But I would phrase if differently. Instead of saying “The other versions DO NOT have a similar efficiency value,” I would say, The lighter the version, the BETTER the mileage and the BETTER the acceleration.” Aptera is conservatively estimating the miles/kWh for the worst version. I like that word, conservatively. Oh, I don’t like that word “worst” which would indicate degrees of bad, and I see nothing bad about Apter. Let’s say Aptera is conservatively estimating the mile/kWh for the least efficient version. Yeah, that’s better.
- This reply was modified 2 months, 3 weeks ago by Francis Giroux.
MemberApril 15, 2022 at 12:49 pm
I don’t understand what you’re saying – I wanted to remind you to use lower wh/mile figure when planning your journey. I’m thrilled that it will be lower, of course.
I also want to have estimated efficiency values for the other variants.
MemberApril 15, 2022 at 6:17 pm
I have seen estimates calculated by others in another forum but I don’t remember where. They are out there if you search through the different forums.
MemberApril 16, 2022 at 7:53 am
You know, there is another option… buy the 1,000 mile version, start with a full charge and go for it. If you can get the consumption down to the levels you described then making the trip on a single charge shouldn’t be a problem. Any solar power generated along the way would contribute to an increase in traveling speed.
- This reply was modified 2 months, 3 weeks ago by Russell Fauver.
MemberApril 16, 2022 at 11:45 am
I’m not sure how much the mirrors would help, at some level the solar cells will saturate even with cooling, also you will need brackets to lift them above the Aptera so they can reflect the sun down on the Aptera. Caring extra solar panels with a system to get that energy into the Aptera would be much more efficient than mirrors. So it would be best to drive when you cant solar charge. Even with all that 3,000 miles in one month would be a record.