Solar-Powered Electric Motors for EVs That Never Plug In
spectrum.ieee.org
spectrum.ieee.org
The Zoe which is a small electrical car has a 100KW engine for acceleration purposes. It goes 4.5 miles using 1Kwh of power at 31 mph (20C). It will cover that distance in 9 minutes at that speed. 230Watt hours in an hour of charging is a very far way from the 6.9Kwh needed for an hour of driving and this is optimal conditions as people brake/accelerate and travel faster than 31 mph.
This design might reduce the cost from the grid a bit and be useful for camping and trickle charge a bit through the day if its in a car park etc. But its not enough to run even the smallest electrical car today, its an order of magnitude off and even with a 100% efficient panel the cars would need to be 7x more efficient than they are today, and electric cars are already a lot more efficient than combustion engines.
It fundamentally doesn't add up as a concept.
The math doesn’t add up at all.
But they did publish it (and it got some press buzz), so their goal was achieved.
There was a good article recently (maybe it was Washington Post, can't remember), about what will really be needed to combat climate change, and I thought it was pretty great. Did a great job of highlighting the things to focus on that can actually be built fast enough (e.g. overbuilding renewables generation, upgrading electrical grids, "electrify everything", etc.) vs what are just distractions that are too small (or slow to build out) to make a dent in what actually needs to happen. You could perhaps argue with the author on some of the details around the edges, but the main points were pretty unassailable in my opinion.
These proposals that will never amount to more than a drop in the ocean aren't worth wasting time on, and worse than that, they can make people "feel" like they're doing something valuable when they really aren't (see: most plastics recycling).
So, yeah, solar panels on vehicle works as a concept for for bikes, not for cars.
[1] https://www.recumbent.news/2021/05/23/the-ultimate-tilting-s...
That thing is huge. Can't take it on a bus, attach it behind a car like a regular e-bike. Can't ride it in windy weather lest you get tipped over by a gust. Can't ride in rainy weather (well, I suppose you can, if you just rely on your leg power), but at least it shields you from rain, I suppose.
It's just not practical. Leave solar panels stationary where they belong.
A Tesla Model 3 (.24 kWh/mile energy usage) would gain up to a mile of range per hour in the sun with this system.
It’s not much but it’s not nothing either.
If you park outside and live in a city with most of your trips handled by transit and walking it means that you could realistically own an electric car and never plug it in, even in non-ideal conditions.
It’s also nice to know that your car isn’t slowly draining like a smartphone when you’re off mains.
https://www.altestore.com/diy-solar-resources/solar-insolati...
Take 4 kWh/m2
https://insideevs.com/reviews/443791/ev-range-test-results/
Take 3 mi/kwh from the table in the middle
I know my car sits in the sun at my work in the asphalt lot. My commute is 12 miles each way and it would cover half this about half the year
1. It's a model in theory, nothing has been built yet.
2. The model is for a motor that's 88% efficient.
3. There's already motors built in mass-manufactured cars (e.g. Tesla) >90% efficiency.
4. The objective is to have a car that doesn't need to plug-in
5. Such cars already exist, but if you don't plug in you just can't go very far
6. You'll never be able to go very far with such cars, even if they achieve their aim of 88% or even 100%.
7. There's absolutely no detail on why this is technically novel, other than the buzzword of the day 'AI algorithm'
8. There's no technical expertise by the writer, who is an uncritical mouthpiece of the researchers, but also offers no real context as to what competing technology offers in comparison
Why is this deemed relevant or interesting enough for HN?
The Aptera can do pretty well on just solar charging, enough that many people could commute every day and never plug it in (if they can park it in the sun every day, which you can't)
The one thing I hate about car culture is that people (logically) tend to buy the car that fits all their use-cases, even if some of those use-cases occur less than 5% of the time.
For example, when I buy a car I want at it to be able to seat at least 5 people, ideally 6-8. And I want it to be able to carry my furniture if I want to buy some, and stuff I need for a camping trip.
But if I look at the distribution of use cases:
People: I seat 1 person 90% of my trips (e.g. daily commutes to work, groceries). I seat a single partner or friend 8% of my trips. And I seat a whole car 2% of my trips.
Stuff: I buy on average 1 big piece of furniture a year, but typically can have it delivered. I buy 3 items 2nd hand online that I like to use a car for picking up. I move homes every few years and my car isn't really big enough.
Camping: I spend 10 days a year hiking in nature, of which 2 travel days.
So all in all I'd be completely fine with an Aptera type of vehicle for all but about 20 out of 365 days, or about 5% of the time. On those days I need something bigger, a car, or even a van/truck.
I honestly can't wait till we get to a place of seamless renting of vehicles you happen to need that day. Economically it should fundamentally be the cheaper option: sharing production & maintenance costs across multiple users, and increasing average time-in-use vs idle-time, should decrease average cost-of-usage for users. Plus it means you can rent a smaller & cheaper vehicle for 95% of the time, and rent a bigger & costlier vehicle 5% of the time.
This should certainly be cheaper than everyone having a fleet of large vehicles 100% of the time, which sit mostly idle 90% of the day, and are mostly empty during the hours you are using it at partial capacity.
Of course renting vehicles isn't seamless. They're not always available, near you, expensive etc. But every 5 years it's getting better. And once self-driving really arrives (supposing it does, for 90% of trips), I think it'll accelerate the move away from the PC or 'Personal Car', to a 'Mobility Pod on Demand' type of model. Perhaps Aptera like vehicles will remain as the minimum personal car for those 95% of trips that you do with 1 or 2 passengers.
Meanwhile AC permanent magnet motors like the ones used in recent EVs are typically somewhere around 95% efficient as long as they aren't too far outside their optimal RPM/power range.
AC Induction and series-wound DC motors tend to be somewhere around 88%.
For example, the motor controller that goes with the Netgain Hyper9 (not exactly the most cutting-edge drive system) can be run without any cooling at all, though it's highly recommended to connect it to water cooling so it doesn't overheat and derate itself.
https://www.evwest.com/catalog/product_info.php?products_id=...
However, the difference between powering some random electronics and actually making any meaningful impact on EV power usage is two completely different beasts...
It would give you 5-7 minutes in a small electric car with a full days charge. 3-5 minutes in a regular electric car.
You might possibly get as much as an 45 minutes with an electric cargo trike or one of those tiny 2 seat cars with the 1500w drive train.
So sort of can work if you aren’t meaning “car” in the contemporary sense of the word.
This couple [1] are driving right around Africa in an EV powered from solar panels they're carrying with them, and they're using a prototype very expensive and heavy solution to get the direct DC charging to work.
I'm thinking of doing something similar, but I can't figure out how I'll do it without running around 400Ah of 48V Lithium battery. The panels can charge that using a regular old MPPT charge controller (or two). Then I'll run a big inverter (5000W) from that to get to AC power, and plug a regular EV charger into that.
Does anyone have a better solution?
That’s how I would approach it, solar panels feeding an inverter, which feeds the regular old EV charger. Toss in some batteries to store excess power. Might as well use off the shelf parts instead of engineering custom direct DC charging.
Thanks. The challenge is that is all heavy and takes up a ton of space inside the vehicle.
Weight/rolling resistance would be second so battery gravimetric density and better tires is the next thing to improve. We can probably get small sedans slightly under 200Wh/mi or 5 miles for every kWh.
> The team only created a virtual model, but building a working physical model could be a future step.
MPPT is a common feature on solar charge controllers. The news here is that they're using neural networks to make it work slightly better.