Hacker Remix

Aptera's First Solar Road Trip. 300 Miles, One Charge

46 points by geox 4 days ago | 54 comments

arrakark 4 days ago

I think Aptera's vision is fantastic. People are quick to judge the looks or three-wheelness of the car, but I think that's just a symptom of cars being marketed as status symbols nowadays.

I am worried about production. With all of the years it's taking them to get there, they can run out of money at any time it seems. It's unknown if they can raise enough money on their terms to get this thing to production.

russdill 23 hours ago

If you're traveling 300 miles, cargo capacity is pretty important. I feel like this is sacrificing a great deal of what people actually need for a "feature" that is a bit of a solution in search of a problem.

skykooler 22 hours ago

The trunk in the Aptera is actually pretty huge, it's like six feet deep. What's mainly sacrificed is passenger capacity since it's only a 2-seater.

russdill 20 hours ago

It claims 25 cubit feet which is large but not certainly not huge. It's shaped in such a way that much of that isn't as useful as you'd hope. A fair amount of that area is at or below 12 inches in depth.

tecleandor 19 hours ago

Well, it's not "remodeling your house" big, but in 25 cubic feet you can fit 15-20 cabin size suitcases. That sounds like "family vacations" big.

woleium 5 hours ago

it won’t sell if you can’t put a set of golf clubs in it

ccnjfkggkkcj 21 hours ago

It isn't just the amount of space but the weight of what you plan on hauling that will impact your battery range as well.

tromp 19 hours ago

I love everything about this design except for how much the front wheels stick out. Especially here in Europe where roads are narrow and parking spaces can be tight, I'd worry about those wheels hitting things or scratching curbs. But even ignoring the front wheels, I agree ordering from this company with no guaranteed medium (let alone long) term viability would be a big gamble.

mlsu 4 days ago

I love these things. Sadly, it’s like an Elven artifact: a beautiful elegant thing, built for people who just aren’t quite like us. Us (the mass market, 99% of car buyers) are orcs. We look at a thing like this and can’t see the beauty or utility of being efficient and having a light footprint.

quailfarmer 22 hours ago

What's new here? College kids have been doing this since the 90s: https://en.wikipedia.org/wiki/World_Solar_Challenge

rcxdude 19 hours ago

Having worked on one of the cars for this, I don't think solar panels on cars actually makes much sense for useful cars. If you can put them on cheaply enough, then they are maybe a nice free boost in some circumstances, but the compromises in the design needed to get the efficiencies necessary for solar panels on the car to power the car are quite extreme.

trhway 22 hours ago

Some look close to like a real car, that one EV + solar, 25miles/KWh https://en.wikipedia.org/wiki/UNSW_Sunswift#/media/File:Suns...

I'd venture a guess - Aptera went for 3 wheeler because certification as a motorcycle is much easier than as a 4-wheel car. Unfortunately 3 wheels - 3 vertical columns resisting the upcoming air - may be less aerodynamic than 4 wheels which are only 2 vertical columns resisting the upcoming air. Add to that that for the same stability you generally need the paired wheels in a 3 wheeler wider than the paired wheels in a 4 wheeler - that again worsens the 3-wheeler aerodynamics.

rcxdude 19 hours ago

There's two different classes in the WSC - one is basically 'make a race car' with very little view to practicality, most of the rules are about limiting the competitive speed to be below the speed limit and having some semblance of safety. Entries to this one are almost always 3 wheeled because it's optimal from an efficiency point of view (aerodynamics and rolling resistance). (Two-wheeled designs are not allowed). The other class (which the car you linked entered under) is meant to be a bit closer to a practical vehicle, and one of the rules is that it needs to have four wheels. It also is allowed a larger battery, which can be charged at certain points during the race (the other class starts with a fully charged battery but it's nowhere near enough for the race, and only solar power is allowed from that point on).

tromp 18 hours ago

Optimal aerodynamic efficiency on a 4 wheel car still requires a narrower rear, with a corresponding shorter rear axle to make the rear wheels roll in the slipstream of the front wheels. This can be seen on two of the most aerodynamic cars of all time, the GM EV1 and Mercedes EQXX.

trhway 18 hours ago

>make the rear wheels roll in the slipstream of the front wheels.

thanks. That is in general what i meant by saying "4 wheels which are only 2 vertical columns resisting the upcoming air", i missed the shorter axle as being the most aerodynamic, and your description is just much better and more right detail level correct.

pinkmuffinere 23 hours ago

> Even on an overcast day, the team saw over 545 watts of solar input

Let’s (generously) assume that was the minimum they saw, and let’s (generously) say they charged for 14 hours. That’s 7.63 kWh gained over the day, in almost ideal conditions. Flagstaff’s high altitude means stronger sunlight, and they can do regenerative braking as they come down the mountain. In my Nissan leaf, 6 kWh would get me about 20 miles. If they are much more efficient, they maybe got 50 miles from the charging on that day, and the other 250 from the charge they started with.

I’d love to be wrong about any of the above! Solar panels on cars would be so cool! It just doesn’t seem useful. Please correct me if I’m mistaken.

gpm 23 hours ago

For roadtrips, you're absolutely right.

The average car travels less than 50 miles on the average day though (more like 30 I believe). This means you don't have to charge except on roadtrips (provided you can park outside in the sun, and don't drive more than average. The battery can provide some smoothing out of day-to-day variability though).

Whether not having to plug in at home is particularly useful... hard to know if it's something consumers want.

NewJazz 12 hours ago

If you are parked outside in the sun, you'll need to spend some amount of energy keeping the battery at a healthy operating temperature.

GavCo 18 hours ago

Fully agree. The physics of solar panels on cars just doesn't work. It's bizarre that this is actively pursued by startups and concept cars from large manufacturers when it takes just quick back-of-the-napkin math to see.

A car has about 5 m^2 of flat space on the roof/hood/trunk so that's the maximum surface area that can capture solar energy at any given time.

The total energy to hit the area is 1000 w/m^2.

The panels can't rotate to track the sun so the effective area is the cosine of the angle. So you end up with about half the amount of effective sunlight hours as the actual daylight hours. So in summer you get about 6 hours of effective sunlight.

Good panels in real world conditions can give you 22% efficiency.

So in optimal conditions you get: 5 * 1000 * 6 * 0.22 = 6.6 kwh

That will reflect your best days. It can be dramatically less if it's cloudy, overcast, winter, far from the equator, car is dirty, parked in shade, etc.

6.6 kwh is about one tenth of the battery in my Hyundai Kona EV. With very conservative highway driving, 6.6 kwh can get about 40km of range and about 50km in city driving. It's what I get from plugging into my home charger for 30 min and what you get from a fast charger in about 3 minutes.

So besides some very niche uses, there's no sense in massively increasing the cost and complexity of a car by installing solar panels. Far better to put the panel on the roof of parking and just plug in for a few minutes while you park.

KeplerBoy 22 hours ago

Have you looked at the thing? I wouldn't be surprised if it's an order of magnitude more efficient than most electric cars out there.

Earw0rm 22 hours ago

The energy dynamics will be closer to a heavy ebike or light motorcycle.

500-600 watts is plenty for moving along at 30-40mph, and with such a light bodyshell, you don't want to be going a lot faster than that.

Standard automobiles are something of a vicious cycle energy-wise - weight, range and speed aren't a linear relationship, so on short-range trips we're paying a huge efficiency penalty for long-range capability. Golf buggies, ebikes and so on can be 1/10th the weight and 1/10th the energy consumption.

LeoPanthera 23 hours ago

50 miles of free driving a day sounds incredible, but you're implying that's a bad thing? I'm confused.

nindalf 20 hours ago

With how cheap solar panels are getting, why not slap a few of them on the roof of every EV? Some days they get you 10 free miles, other days 20 or 30. If you’re a commuter, you’re basically driving for free at that point.

Sure it’s not enough on road trips, but why is that a problem?

rcxdude 19 hours ago

The solar cells themselves may be cheap, I don't think putting them on the roof of a car (without ruining the aerodynamics) is particularly cheap, yet. Most people would be better served putting the solar panels on the roof of their house.