Aptera's First Solar Road Trip. 300 Miles, One Charge | Hacker News Reader

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

aptera.us

49 pointsgeox58 comments

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.

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.

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.

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.

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.

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.

For a family of two?

I guess it could be a family of four if you have two of them and both parents drive.

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

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.

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.

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

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.

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).

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.

>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.

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.

> 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.

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.

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.

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

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?

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.

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.

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.

Yes also any one with a ev knows speed matters. Its not stated how long it took or average speed over the course. Not to mention a nice draft from the film car. Besides all that I would still love to have one.

Their marketing and reserve page claims "up to 40 miles per day": https://aptera.us/vehicle/

You are not wrong, you are just missing the point. This is the ultimate commuter vehicle. Most commutes fall in the 10-30 miles range. On an average day, you might drive 30-40 miles. If so, you basically are powered by the sun on most days.

> they maybe got 50 miles from the charging on that day

They claim it's up to 40.

Best case you charge more than you drive; so your car has a enough in the battery every morning to make it back home after work. Worst case, you delay the moment when you have to charge by plugging in by some large percentage. The difference between charging your car once or twice per week and once or twice every few months top top it up. Perfect if you don't have a charger at home. Removes a lot of the hassle and cost related to charging.

Road trips are not something people do on a daily basis. Especially not in light/small vehicles. But when you do, a light vehicle with a longish range is a nice thing to have. And this thing is very efficient by design (light, teardrop shaped) and the relatively small battery probably charges pretty quickly. And you get a few tens of miles extra because of the solar. So it can do a 300 mile journey despite having a smallish battery. Which is what they just demonstrated. 300 miles is pretty good. Most EVs don't do any better than that.

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.

I have always adored Aptera, but BYD and Tesla will always eat their lunch. I've been out to the factory in San Diego and driven Luna. It was awesome, but sadly I just don't think it will get funding. The government REALLY screwed them over, not once, but twice with the vehicle loan program. Really wonderful people and an amazing car.

I don't really get what Aptera are aiming for, but solar panels on electric vehicles are a good call in niches already (refrigerated trucks being a low hanging fruit, golf carts) and only set to grow from there.

300-545 watts. Aptera gets 8 miles/KWh (to compare - my Prius and other EV cars get about 3+ miles/KWh). So they get 2.5-4.5 miles from an hour under the Sun. So 20-40 miles during the time of commute and while parked at work.

So, yes, that Trump's idea he expressed in the interview to Musk back then to plaster cars with solar panels isn't totally meaningless, at least in theory - you can have 2-3x solar panels on regular car compare to Aptera, so it would have made sense for daily commute if that plastering of the cars cost close to nothing, and unfortunately putting such thing in production would add thousands to the car cost, and given that even Musk/Tesla with their pile of cash available to dump into engineering of such a new feature haven't yet ventured into it it suggests that at least near future isn't bright for it.

Where does the 8mi/kWh number come from?

https://youtu.be/Kvpn7cteW5U?t=126 straight form Aptera

Not a reliable source.

giving their weight and aerodynamic coefficient - both around half my Prius - it sounds about right.

The price of solar panels isn’t static though. It might not have made sense in 2015 or 2020 or even 2025. But solar panels continue to get cheaper, so it might eventually get to a point where it’s a serious idea. Even if it costs a couple thousand extra, the panels will pay for themselves by giving you basically free commutes forever.

Solar panels get cheaper but the total amount of square meters on a vehicle that you can cover with them remains the same. In something the size of this car if I were purchasing PV cells for it, I would be optimizing by far for STC watt per square cm, not $/watt.

$/watt STC is more for big roof and ground mount PV financial calculations.

mainly it isn't the price of solar panels. How do you put it on the car's curved metal panels (or you're going to redesign the car into something like Cybertruck?) without worsening aerodynamics, without much additional holes and additional weight and in the way that will hold the panels for the next 7-10 years, rain, snow or shine while these panels wouldn't get easily damaged by carwash, etc., and you also need to put all these wires in some sensible way to minimize risk of various failures and repairs and you'd have to price in additional warranty service for all that additional stuff ... so it is a large and expensive thing to put into mass production.

>Even if it costs a couple thousand extra, the panels will pay for themselves by giving you basically free commutes forever.

Say you get 1.5KW, 3x of best Aptera, 8 hours, 12KWh, i.e. about $3.60/day or it can be thought as a replacement of 1 gallon of gas (at 30% efficiency), still $4. Thus $1000/year. And i don't think the feature can be put into cars at $2K. More like $3-$5K optimistically.

Damn, you're absolutely right. The aerodynamics alone kills this idea.

there was a German startup (Sono Sion) some years ago that had a very similar idea and had even prototypes [0], but they filed for insolvency 2-3 years ago. Now I think they pivoted to something more boring and practical - putting solar panels on vehicles. I hope aptera gets to production though

[0] - https://en.wikipedia.org/wiki/Sono_Motors_Sion

There’s also Lightyear. But so far the Zero (formerly One) ran into the ground after a barely existent production run, and the Two I’m not sure exists in any way.

A more effective design might be to tow a very thin and light 20 foot trailer of panels. That could work with any EV.

Focusing on efficiency is a good idea, but why is it so big? It’s silly that it’s over 4m long.

More room for panels.

Because it needs to be that long to have a low air resistance. There are two determining factors for air resistance. First, the cross section A, which determines the amount of air to be moved and second the drag coefficient c, which describes how well the air flows around an object. This gets lower the more "round" a shape is, but the sphere isn't actually the best one, you want the form of a falling raindrop. For that the shape needs to be quite a bit longer than it is wide. So if your car is e.g. 2m across, it needs to be something like 4m long to approach best efficiency. See also the empty "tails" attached to some racing cars for drag reduction.

They could either make it narrower or slightly less efficient.

That length makes it too big in many countries, especially for just two seats.

I think it is already as narrow as you can put 2 seats side by side. But then indeed it becomes a tradeoff between size and efficiency. They went for maximum efficiency. And it is still 26cm shorter than a Model 3. So while not an compact car, not overly large either.

You’re comparing against a car that is difficult to use on UK roads due to its length and (to a lesser extent) width. Perhaps in the US it’s not that big, but here it is.

You can't be serious that the length of a Model 3 makes it difficult to use on UK roads? It is a typical mid size vehicle, there are loads of vehicles of this size and larger on the roads over here.

There are definitely cars that size and bigger and I frequently see their drivers struggle to park or navigate narrow roads.

I'd call something like a Golf/Focus "mid size". There's approximately two sizes below and two sizes above.

Honestly, putting solar panels on EVs/plug-ins is one of those ideas that seems out there but is actually really practical even on production cars.

You can fit a solar panels that can produce at least a couple hundred watts peak on most cars, to as much as 1kW on larger ones, and they are dirt cheap. Those produce enough energy to power your daily commute without ever having to plug them in (something most people either can't or won't bother doing).

seems like an interesting and financially viable concept, just taking a while to get to market

Yeah, 545 watts on an Arizona afternoon in that ugly spaceship-ass lookin thing is exactly what I picture when someone says "solar car". It'll extend your range by a tiny bit and look like shit in the process. I bet 545W doesn't even sustain it at highway speeds, let alone acceleration and deceleration that would be needed on a busy road etc (gee I wonder why they took "the road not travelled").

It's just not a good idea. Sure, put a panel on the roof of a car to power the accessories system and get a little bit back in your range, but if you go into it thinking you can drive a *real* car on the solar power that strikes the surface of the vehicle you're just gonna make yourself look silly.

You and I start from the same base information: the power from the solar in real-time isn't enough to drive a "real car", immediately. But we come to totally different conclusions.

The solar hitting the roof of this thing over the course of a day is enough to make my average commute in that thing. That's what batteries are for. I'm not driving from sun-up to sun-down. (And you can plug it in anytime you want.)

Yes there are some huge trade-offs to make it work: It's not a 3-row minivan, it's not a 4-door sedan, it's a bizzare-looking car-like thing that moves only two people, but does so in the comfort that I desire for my daily use. And the solar part is only going to work out in a sunny place, if you park it in the sun. That happens to be exactly what I'm looking for.

Even if it didn't have solar, it's a ridiculously efficient EV, which I'd prefer over a ridiculously fast car or very large SUV.

I would understand "That seems like a small market" or "that's too many trade-offs for me", but "It's just not a good idea" seems like harsh judgement for a vehicle because it doesn't appeal to your visual preferences or usage.

Agreed, I'd make the same argument as parent for a Harley. It's not my cup of tea, loud, impractical, and a gas guzzler, but it clearly appeals to a bunch of people. Give things a chance for goodness sake. Aptera never claimed you don't need to charge.

I think the car looks excellent for what it is. It’s not like there’s a lot of choice in stunning micro EVs. My friend drove a Buddy for a few years. Really neat car, but that’s definitely one that nobody would call beautiful. I’ve seen many people who thinks the Aptera looks great. It has some very good design qualities (sleek and elegant IMO), even if I can see why others wouldn’t like it.

Like others have said, you’re objectively wrong about the solar panels. If you live in a sunny area, if you don’t have off-street parking, and you just need something to commute to work and do errands, the Aptera is technically an excellent choice. You would rarely have to visit a charging station. There’s no denying that the Aptera js efficient enough that the roof solar actually has a meaningful impact for people with median daily use.

The solar panels aren’t meant to make a huge impact on long road trips. So your criticism just doesn’t make any sense. I can kinda understand the confusion considering we’re commenting on this story in particular. But this test is more about demonstrating what the excellent aerodynamics brings to the table. So maybe read a bit more into the intention of the design choices before critiquing it?

These guys are based here in San Diego county. I've been watching them for years.

It's good to see some new news, and I think the road trip and report are an interesting update.

But I do think they could have avoided criticism like what we're replying to above, if they had stated clearly how much of the 300 mile day was powered by the photovoltaic, and how much relied on plug-in charging.

I'm not critical at all, and I still want to know those details 8-/

Solar powered daily errands and even a modest commute are totally viable here in the southwest. I work from home, and plug my Nissan Leaf in about twice a week. So that's about 300 miles per week. I could almost certainly do my driving in the aptera without plugging in at all.

The look is strictly "form follows function", it's not intended to be a fashion statement, it's intended to be maximally efficient.

Clearly trying to attract Kunk Daddy and the thug crowd away from giant blacked-out escalades with gold wheels, isn't the demographic addressed by this vehicle.

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