4 ms·

Solar-Powered Electric Motors for EVs That Never Plug In

18 points by mfiguiere 3y ago

hyperhello 3y ago
Nothing has been built or planned to be built, it’s just someone proposing the idea.
awiejrta 3y ago
Seems like the only novel part of this is suggesting we use a neural network to plan something related to solar panel tuning? And then it seems like another case of using the fanciest possible method to get a paper published, because linear regression would probably work better and be easier to implement? And then there's the simple fact that you can't power a car with solar panels on its roof because 1sq-m of solar panels won't produce anywhere near enough power, unless you only plan on driving to the mailbox and back once every other day. Am I missing anything?
BHSPitMonkey 3y ago
The newest Prius has a solar roof option, which in good conditions seems like it can reclaim a few miles of driving range per day. We're a far cry from "never plug in", I think.
- lm28469 3y ago
  It's more of a "unlimited AC when parked" than a "unlimited range" type of thing
- tootie 3y ago
  It seems like an incredibly useful tool for avoiding being stranded but I expect we're many years away from a vehicle that run optimally on solar power even in a desert.
  - jackmott42 3y ago
    It doesn't help with being stranded on any normal car. Better off walking.
- timbit42 3y ago
  The Aptera is more of a "never plug in" vehicle, if you live in a sunny area. https://www.youtube.com/watch?v=mpiH-Y-HOvE https://www.youtube.com/watch?v=mpiH-Y-HOvE
elihu 3y ago
> The system relies on AI to optimize the solar array’s output and operate the motor at 88 percent efficiency; real-world DC electric motors have efficiencies of 75 to 80 percent. 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%.
- hinkley 3y ago
  What's the conversion efficiency of DC-AC these days?
  - deleted 3y ago
    [deleted]
  - elihu 3y ago
    I'm not sure. There must be some losses, but considering that motor controllers these days are fairly small and only need some modest active cooling I'd guess they're pretty efficient. 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=482 https://www.evwest.com/catalog/product_info.php?products_id=...
mikeiz404 3y ago
I’m going to avoid critiquing the title but incase this gets missed… > The team only created a virtual model, but building a working physical model could be a future step.
PaulKeeble 3y ago
At 1m^2 for the panel and a top end panel its going to peak out at ~230W. In an hour that is 230 Wh. That is 230Watts during the peak hours of the sun assuming its angled to directly capture the sun, which it doesn't appear to be in their concept CGI. Its probably going to be less than that. 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.
- rbanffy 3y ago
  Besides, it’s probably a better idea to always extract peak power from the solar array to charge the battery and let the motor use it at its own peak efficiency. The math doesn’t add up at all. But they did publish it (and it got some press buzz), so their goal was achieved.
- hn_throwaway_99 3y ago
  At this point, I think we should be willing to call out these ideas for being unhelpful distractions from what will really be needed to combat climate change. As you point out, the math just doesn't add up. Photovoltaics on car roofs is just a dumb idea, beyond perhaps some novelty charging of accessories (e.g. running the A/C on hot, sunny days). 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).
NoLinkToMe 3y ago
Weird article. 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?
- jackmott42 3y ago
  regarding #6: 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)
  - NoLinkToMe 3y ago
    Agreed looks really cool. Would love to see this become the future of mobility. 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.
pengaru 3y ago
Aptera has a solar-charged reverse trike EV that manages some impressive range from a day's worth of LA sun. If the panels ever get closer to 100% efficiency it'd make a great little commuter for sunny locales.
- chris222 3y ago
  The biggest advantage is the shape which drastically reduces air resistance and 3 wheels which reduces rolling resistance. Everything else in an EV is almost as efficient as it can possibly be. Aptera is about 100Wh/mi while a tesla model 3 is 200-250. 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.
  - timbit42 3y ago
    Confirmation of your stats here: https://www.youtube.com/watch?v=mpiH-Y-HOvE https://www.youtube.com/watch?v=mpiH-Y-HOvE
K0balt 3y ago
The energy that they could harvest from that panel would move an electric bicycle or scooter nicely around 15km/hour on flat ground. 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.
filleokus 3y ago
A friend of mine has a solar panel on top of his old small hatchback. The car itself is petrol powered, but he has a surprisingly expansive 12V system all over the small cabin, including some Li-ion battery packs. This powers everything from a fridge to charging stations for go pro's and a raspberry pi. Before the solar panel he sometimes had to drive around the car just to recharge the li-ion batteries from the generator, but with the panel's it's essentially self sustaining. However, the difference between powering some random electronics and actually making any meaningful impact on EV power usage is two completely different beasts...
- chris222 3y ago
  Everything except cooling/heating and propulsion uses an insignficant amount of power.
grecy 3y ago
I wish we could charge modern EVs directly from Solar/DC. 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? [1] https://www.instagram.com/4x4electric/ https://www.instagram.com/4x4electric/
- deleted 3y ago
  [deleted]
- quickthrowman 3y ago
  > 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. 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.
  - grecy 3y ago
    > 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.
- chris222 3y ago
  The biggest problem is you need to match the pack voltage when DC charging.
p1mrx 3y ago
https://en.wikipedia.org/wiki/Maximum_power_point_tracking https://en.wikipedia.org/wiki/Maximum_power_point_tracking 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.
- rasz 3y ago
  but do they? MPPT is a solved problem and you cant do better. As far as I can see this is someone throwing few buzzwords (AI, free energy motor) and managing to get himself published in IEEE blog. Author didnt even build anything, just wrote a Matlab model.
  - p1mrx 3y ago
    I don't disagree. Perhaps it is totally bogus.

18 points by mfiguiere 3y ago

Nothing has been built or planned to be built, it’s just someone proposing the idea.

Seems like the only novel part of this is suggesting we use a neural network to plan something related to solar panel tuning? And then it seems like another case of using the fanciest possible method to get a paper published, because linear regression would probably work better and be easier to implement? And then there's the simple fact that you can't power a car with solar panels on its roof because 1sq-m of solar panels won't produce anywhere near enough power, unless you only plan on driving to the mailbox and back once every other day. Am I missing anything?

BHSPitMonkey 3y ago

The newest Prius has a solar roof option, which in good conditions seems like it can reclaim a few miles of driving range per day. We're a far cry from "never plug in", I think.

lm28469 3y ago
It's more of a "unlimited AC when parked" than a "unlimited range" type of thing
tootie 3y ago
It seems like an incredibly useful tool for avoiding being stranded but I expect we're many years away from a vehicle that run optimally on solar power even in a desert.
- jackmott42 3y ago
  It doesn't help with being stranded on any normal car. Better off walking.
timbit42 3y ago
The Aptera is more of a "never plug in" vehicle, if you live in a sunny area. https://www.youtube.com/watch?v=mpiH-Y-HOvE https://www.youtube.com/watch?v=mpiH-Y-HOvE

elihu 3y ago

> The system relies on AI to optimize the solar array’s output and operate the motor at 88 percent efficiency; real-world DC electric motors have efficiencies of 75 to 80 percent. 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%.

hinkley 3y ago
What's the conversion efficiency of DC-AC these days?
- deleted 3y ago
  [deleted]
- elihu 3y ago
  I'm not sure. There must be some losses, but considering that motor controllers these days are fairly small and only need some modest active cooling I'd guess they're pretty efficient. 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=482 https://www.evwest.com/catalog/product_info.php?products_id=...

mikeiz404 3y ago

I’m going to avoid critiquing the title but incase this gets missed… > The team only created a virtual model, but building a working physical model could be a future step.

PaulKeeble 3y ago

At 1m^2 for the panel and a top end panel its going to peak out at ~230W. In an hour that is 230 Wh. That is 230Watts during the peak hours of the sun assuming its angled to directly capture the sun, which it doesn't appear to be in their concept CGI. Its probably going to be less than that. 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.

rbanffy 3y ago
Besides, it’s probably a better idea to always extract peak power from the solar array to charge the battery and let the motor use it at its own peak efficiency. The math doesn’t add up at all. But they did publish it (and it got some press buzz), so their goal was achieved.
hn_throwaway_99 3y ago
At this point, I think we should be willing to call out these ideas for being unhelpful distractions from what will really be needed to combat climate change. As you point out, the math just doesn't add up. Photovoltaics on car roofs is just a dumb idea, beyond perhaps some novelty charging of accessories (e.g. running the A/C on hot, sunny days). 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).

NoLinkToMe 3y ago

Weird article. 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?

jackmott42 3y ago
regarding #6: 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)
- NoLinkToMe 3y ago
  Agreed looks really cool. Would love to see this become the future of mobility. 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.

pengaru 3y ago

Aptera has a solar-charged reverse trike EV that manages some impressive range from a day's worth of LA sun. If the panels ever get closer to 100% efficiency it'd make a great little commuter for sunny locales.

chris222 3y ago
The biggest advantage is the shape which drastically reduces air resistance and 3 wheels which reduces rolling resistance. Everything else in an EV is almost as efficient as it can possibly be. Aptera is about 100Wh/mi while a tesla model 3 is 200-250. 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.
- timbit42 3y ago
  Confirmation of your stats here: https://www.youtube.com/watch?v=mpiH-Y-HOvE https://www.youtube.com/watch?v=mpiH-Y-HOvE

K0balt 3y ago

The energy that they could harvest from that panel would move an electric bicycle or scooter nicely around 15km/hour on flat ground. 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.

filleokus 3y ago

A friend of mine has a solar panel on top of his old small hatchback. The car itself is petrol powered, but he has a surprisingly expansive 12V system all over the small cabin, including some Li-ion battery packs. This powers everything from a fridge to charging stations for go pro's and a raspberry pi. Before the solar panel he sometimes had to drive around the car just to recharge the li-ion batteries from the generator, but with the panel's it's essentially self sustaining. However, the difference between powering some random electronics and actually making any meaningful impact on EV power usage is two completely different beasts...

chris222 3y ago
Everything except cooling/heating and propulsion uses an insignficant amount of power.

grecy 3y ago

I wish we could charge modern EVs directly from Solar/DC. 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? [1] https://www.instagram.com/4x4electric/ https://www.instagram.com/4x4electric/

deleted 3y ago
[deleted]
quickthrowman 3y ago
> 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. 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.
- grecy 3y ago
  > 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.
chris222 3y ago
The biggest problem is you need to match the pack voltage when DC charging.

p1mrx 3y ago

https://en.wikipedia.org/wiki/Maximum_power_point_tracking https://en.wikipedia.org/wiki/Maximum_power_point_tracking 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.

rasz 3y ago
but do they? MPPT is a solved problem and you cant do better. As far as I can see this is someone throwing few buzzwords (AI, free energy motor) and managing to get himself published in IEEE blog. Author didnt even build anything, just wrote a Matlab model.
- p1mrx 3y ago
  I don't disagree. Perhaps it is totally bogus.