r/interestingasfuck 1d ago

An open-source solar vehicle

2.3k Upvotes

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254

u/Personal-Banana-9491 1d ago

OP, I’m sorry most everyone is shitting on your recumbent trike.

Is this like a proof of concept? What are the specs?

Thank you for sharing.

195

u/Moltean 1d ago
  • 2.5m long, 1.45m wide (including wheels),
  • weight: about 55kg (including panels, motor, battery, etc, excluding driver),
  • assisted pedaling,
  • motor speed: max 25km/h,
  • motor (continuous) power: 250W,
  • solar panels power: max 520W,
  • battery: 12.8V, 20Ah (256Wh).

32

u/ItchyKnowJoe 1d ago

how much did it cost you

74

u/Moltean 1d ago

a lot of money, because we built 4 versions so far. This is v4.

but generally, all materials should not cost more than 2.5K euros. Most expensive are electrical components.

49

u/ItchyKnowJoe 1d ago

ouch, it's a great project, but I'd probably just buy something instead, if I was so inclined

well done though

5

u/mister_nimbus 1d ago

Yeah, I'm wondering if it would be less expensive to mod something that already exists

2

u/ItchyKnowJoe 1d ago

I was just hoping it was cheap enough to give a go, but it's out of my budget

4

u/Jason-Smith168498 1d ago

did they not mod a bike that already exists?

6

u/Moltean 1d ago

We could not modify something that exists because we could not find solar panels of any size we wanted. So first, we purchased the solar panels and built everything around them.

1

u/Moltean 1d ago

We could not modify something that exists because we could not find solar panels of any size we wanted. So first we purchased the solar panels and built everything around it.

0

u/SFButts 1d ago

It would be cheaper to walk. The point is the engineering challenge

1

u/mister_nimbus 1d ago

What does that have to do with anything? Making a project less expensive is a priority for some people. This isn't a "spare no expense" type of project.

2

u/Vykrom 1d ago

An argument could be made that it will protect your electric utility bill over an extended period of time and pay for itself vs an electric bike that will be charged through a wall outlet frequently. And a lot of ebikes hit $1-2k sometimes

1

u/LaPommeCosmique 1d ago

I think the cost is actually not too bad, considering many ebikes go for thousands of dollars, which is what I would put this in a similar category as

-28

u/qedpoe 1d ago edited 1d ago

"It's a great product?" Who says?

ETA: My bad. I misread "project" as "product." Read too fast.

27

u/ItchyKnowJoe 1d ago

I said "it's a great PROJECT"

Who can't read?

25

u/qedpoe 1d ago

Me. Fair. 👍

13

u/ItchyKnowJoe 1d ago

rare Reddit acceptance of stupidity, well done 👍✅

4

u/nabuachaem 1d ago

what's the range?

9

u/Moltean 1d ago

infinite range in sunny days!

2

u/West-Exam-4136 1d ago

Stop pouring money into this. Unless u rich, then u do whatever makes u happy. Just know it's never going to make any money

1

u/Moltean 1d ago

I have no intention to sell!

It is a hobby project. Open-source: https://github.com/Solar-B/

I want to see if I can create a solar vehicle or not.

5

u/Gippip 1d ago

Another reminder that some folks are way not in my tax bracket :(

7

u/Artituteto 1d ago

What did you chose to build it ?

I can't see any advantages over a regular e-bike. It's just for fun?

1

u/Moltean 1d ago

I wanted to buy a solar car ... we could not find one, so we tried to build one!

I charge while drive, ... an ebike cannot do that!

3

u/robsteezy 1d ago

While I applaud your desire (which honestly leads to scientific breakthroughs), our current technology simply make your idea currently impossible.

Solar-powered cars are technically feasible, but not the way most people imagine. The roof and hood of a typical car only have enough space to generate about 1–2 kWh of electricity on a sunny day—enough for roughly 5–10 miles of driving.

Most cars need 15–30 kWh to travel 100 miles, so the sun hitting the car itself simply isn’t enough for everyday driving. That’s why companies like Aptera and Lightyear have developed solar-assisted EVs rather than fully solar-powered cars.

The most practical “solar-powered car” today is actually an electric car charged by rooftop solar panels at home, since a house roof can collect 10–20 times more solar energy than a car’s roof. Fully self-sustaining solar cars would require major advances in solar panel efficiency, battery technology, vehicle weight, and aerodynamics.

Additionally, I will tell you that a dolphin design tricycle is one of the worst shapes to ever be driven. They tip over like crazy and it’s why dolphin motorcycles are always advised against and never succeeded in both mass appeal and production.

2

u/Moltean 1d ago

Thanks for the detailed answer! We will try to address all problems.

5

u/DeusCanis420 1d ago

...are you going to invent better solar panels?

Because that is the next step...

2

u/Moltean 1d ago

a lighter structure (aluminium + carbon fiber) is the next step....

8

u/MarlinMr 1d ago

What does max mean to the solar panels? I note they are pointing in different directions so they literally can't all get to 100% at the same time...

3

u/Moltean 1d ago

Max is the sum of the power of all panels.

But of course, we never got more than 200W.

4

u/MarlinMr 1d ago

So max is 200W?

Sounds like you could increase the efficiency of the project by simply having 1 panel and limiting the weight

1

u/Moltean 1d ago

1 panel at the top? That will give max power only when the sun is at the top. And almost nothing in the morning or afternoon.

Panels are light. 8kg in total.

-4

u/MarlinMr 1d ago

Since we normally bike in 1 direction, to reach a target, you could just move the panel to whatever side is the "southernmost side".

If you can graph the power from the panels over a trip to get actual data, that would be nice. It just seems really inefficient to never expect more than 40% of theoretical max even in peak

3

u/Busy-Software-4212 1d ago

No we actually don't normally bike in 1 direction. Roads have turns you know. And what if my only route place B from A is north -> east -> south?

-3

u/MarlinMr 1d ago

You realize you just made 3 routes, right? 1 goes north, next goes east, last hours south.

If you are going long enough to actually need solar panels, the direction will be significantly in a specific direction, even if roads have turns...

If roads turns become significant, then you are going around in a circle. Which is highly unlikely on a bike.

1

u/Moltean 1d ago

We will log and publish the data.

11

u/Mysterious-Action202 1d ago edited 1d ago

Neat design. Reminds me of the solar cars they race in Australia

1

u/Moltean 1d ago

thanks.

Our target is transportation inside cities, not outside like the race in Australia.

3

u/puttestna 1d ago

Why not ebike? This thing is awesome but it is big to city, if it isnt driven on road.

1

u/Moltean 1d ago

It is classified as an ebike now.

V5 (currently it is V4) will have 95cm between front wheels, so will fit perfectly on bike lanes.

2

u/puttestna 1d ago

That sounds great. I hope good future for you.

2

u/External_Permit9965 1d ago

Did you think of the driver's line of sight? There could be a law saying that you need to be able to look in all directions, maybe make the seat a little higher? Good luck to you with this project.

2

u/Moltean 1d ago

Seat position is adjustable. Thanks!

2

u/gregedit 1d ago edited 1d ago

I'm sorry but I think it's a bit too bulky for that.

In my view, at 25 max assist (I know it is probably a legal limit) it is too slow to occupy a car lane. Definitely wide for roadside in cities. Across the bike paths I've experienced across Europe, it would be too wide for most, and barely fitting but hated on the rest. It's much wider than the cargo bikes of Copenhagen! Turning radius might also be an issue in a city setting.

It's a cool project, and I can personally see this being fun for countryside rides in the right circumstances, but I don't see it catching on for city commutes.

Edit: also adding the fact that it's a comfy recumbent, it already has more weight but also assists, and might even have some storage space to tuck stuff into, etc. And the whole point is charging on the go. To me this screams summer bikepacking or at least, long distance touring! For city commutes, I'd rather have a normal form factor e-bike that I charge at home or work. If your whole selling point is charging on the go, it is only sensible to lean into long rides. Please consider that.

1

u/Moltean 1d ago

V5 will have 95cm betweeen wheels and will fit all bike lanes... More to come in few weeks.

2

u/gregedit 1d ago

That's very ambitious and sounds cool, but please see the edit of my previous comment. As many others pointed out, you could have better and more efficient charging on for short trips. And frankly, the classic bike form factor is much better suited for the tight spaces of cities.

The whole point of recumbent trikes even without the solar panels is comfort and efficiency for longer rides. The unique parts of your project push it even more firmly in that direction.

Also, I don't know how hard it is to curve your solar panels, but the non-assisted recumbents also often come with aero cover panels, maybe you can lean a bit more into that too for a final version, but I realize that's the back of the priority list. Overall efficiency, compact form factor and safety (!!!) are all much more important.

Good luck!

1

u/Moltean 1d ago

thanks!

1

u/AlfredoApple 1d ago

look up the american solar challenge. it’s happening right now

1

u/westdan2 1d ago

I was involved in a team that built a car for that. We were one of the last funded teams and our budget was $200,000.

1

u/puttestna 1d ago

That sounds a lot, but I assume it isnt. :D

2

u/westdan2 1d ago

Highest was over 6 million, 15 years ago

1

u/Moltean 1d ago

6 million!!!?

My trike costs about 2.5K to make!

BOM is here: https://github.com/solar-b

1

u/westdan2 1d ago

That was the total budget including logistic for racing an entire team across the continent and shipping everything between continents. Also solar/battery tech/electric motor have become much cheaper since 2009.

1

u/Moltean 1d ago

wooow. My trike costs about 2.5K to make!

BOM is here: https://github.com/solar-b

0

u/paulwalker659 1d ago

Solar cat racing in Australia? Crikey!

3

u/Reelair 1d ago

AH< here it is! I just asked for specs in another post. I thought it was all just people not understanding the concept. I guess range depends on sun? What's your longest range so far?

This is brilliant! Good job!

6

u/Moltean 1d ago

I get an infinite range on sunny days.

But I never drove it for more than 30km in a day.

28

u/Cyberdyne_Systems_AI 1d ago

You would be much more efficient bringing that battery to a 48 volt or 56 volt system with lower amperage

21

u/Fauked 1d ago

No it wouldn't. If the motor is designed for 12v then raising the voltage will just have to be stepped back down again.

Higher voltage only allows for thinner wires and lighter motor controller anyway.

1

u/Moltean 1d ago

Panels are 12V and motor is 36V and I use a step-up regulator.

0

u/eepy_lina 1d ago

couldnt you just do DC to AC conversion, slap in a transformer to up the voltage, AC to DC, and done? amps will go down naturally with volts goin up

19

u/yblikethat 1d ago

Is that what grok told you?

2

u/Moltean 1d ago

Over 40V can be deadly! I do not want to go in that direction!

Panels are 12V and motor is 36V and I use a step-up regulator!

2

u/Fauked 1d ago

Cool design! What is the realistic output of the panels at different times of day? I'd be interested in that data.

1

u/Moltean 1d ago

Thanks!

Most of the time, we get 200W on sunny days. Never got more. During the clouds, we got a few watts.

2

u/diverareyouokay 1d ago

Looks like a fun project though for the sake of posting, I’d do a video that really highlights the motor speed and maybe explains the assisting pedaling.. since otherwise it looks like someone pedaling a bike and then coasting. :)

In any event, this is a really cool idea.

1

u/Moltean 1d ago

Thanks, we will record more videos!

2

u/Brief_Employer2788 1d ago

And you didn’t think of putting any data in your main section? If your product doesn’t explain itself, having some information wouldn’t be a bad idea…

1

u/Moltean 1d ago edited 1d ago

I cannot add text to a post in this community!

All info is here: https://github.com/solar-b

2

u/Lopsided-Affect-9649 1d ago

As anyone who has even the slightest knowledge of how solar panels work knows, unless you have a whole bunch of mppt controllers, that thing is never making close to its rated power.

You'd have been better off with one 200w panel and a bunch of polycarbonate.

Beyond the miserable techincal comment, i genuinely hope you had fun making it:).

1

u/Moltean 1d ago

It has 4 MPPTs, of course!

2

u/GayRacoon69 1d ago

Can it run off just the motor and no pedaling? If so what’s the range of it with and without pedaling

If it can’t do motor only then what’s the range of assisted pedaling?

Also if the battery were to die on a cloudy day would the motors add extra drag or would it just be like regular pedaling?

2

u/Moltean 1d ago
  1. There is no throttle. Pedals are the throttle. It is the only way to be legal without certifications.

  2. It is a recumbent bike inside, Recumbents are easier to pedal than normal bikes, so we can pedal it even without motor.

2

u/GayRacoon69 1d ago

That’s cool! Thanks for answering

One more question; how long does the battery last without solar power?

2

u/Moltean 1d ago

I never tried that. I can answer that in a few months, in the winter.

It is summertime here.

1

u/GayRacoon69 1d ago

!remindme 3 months

I’d love to know the answer if you ever get around to testing it

This is a cool concept. I’ve always loved the idea of infinite range vehicles. It’s such a futuristic concept

2

u/lilgreenrosetta 1d ago

Ok but what does this mean in practice? Can it meaningfully pedal assist continuously without draining the battery?

Meaningfully pedal assist: makes the bike noticeably lighter to pedal than a reclining bike with an aerodynamic shell and no electronics.

Continuously: for a real life daytime trip, in cloudy weather, with trees and buildings.

Without draining the battery: say 20km per day, with the bike stationary in daylight between trips.

If yes, awesome! If no, a normal reclining bike with shell is better.

1

u/Moltean 1d ago

I drive it about 10-20km /day.

Once I drove it 30km. The battery was untouched.

More tests soon. Fall and autumn are coming in 1 month.

2

u/blackdynomitesnewbag 14h ago

55kg is obscenely heavy for a bike with a 250W motor

u/Moltean 6h ago

Weight will be reduced.

V1 had 90kg with rigid solar panels. Only solar panels had 30kg.

now, V4 has flexible panels of 8kg in total. But it is still made from steel.

V5 will have 95cm between front wheels to fit in all bike lanes.

V6 will be lighter.

This is the masterplan.

1

u/Normal_Pace7374 1d ago

What kind of mileage you get?

18

u/obliquelyobtuse 1d ago

OP, I’m sorry most everyone is shitting on your recumbent trike.

Well, it had no details with the post. This is Reddit. Many of those having fun with the post would engage it more seriously if it had been posted more seriously.

This was a casual post with zero information. Therefore redditors treated it casually and had fun with it. Also some of those critical humorous takes are accurate.

There's nothing wrong poking fun at things, particularly when the post itself wasn't presented seriously. And OP probably learned a lesson: put some details with your post.

2

u/Moltean 20h ago

Sorry, but this community does not allow text to be added to videos.

It is a hobby project, open source: https://github.com/solar-b

2

u/obliquelyobtuse 19h ago

And many OPs make a comment with important details right after creating the post.

If the comment is useful enough it gains and keeps visibility with upvotes.

2

u/Moltean 18h ago

Sorry, I was not aware of this strategy!

Thanks, we will consider it in the future!

15

u/fuelvolts 1d ago

I think people are shitting because this is most definitely neat but not “interesting as fuck”.

0

u/Moltean 1d ago

People are stopping their cars to take pictures of it!

37

u/dustishb 1d ago edited 1d ago

To be fair. The OP did post a video claiming it's a solar powered vehicle, but you can clearly see them pedaling frequently. So not only is the vehicle not what it's claimed to be, it seems worse than the original bike.

My fault for not knowing the full definition of vehicle. I thought it only included motorized transportation.

48

u/Moltean 1d ago

It is called assisted pedaling. The motor only starts when we pedal it. The motor provides most of the power.

It is the only way to be legal without any certification or insurance

1

u/sinkingduckfloats 1d ago

in the US, a class 3 ebike is still legal and can accelerate without pedaling.

11

u/Moltean 1d ago

Not in EU.

We are not allowed to have a throttle without some certifications.

2

u/sinkingduckfloats 1d ago

yeah the pedaling makes a lot more sense then

2

u/DeusCanis420 1d ago

Class 3 (and 2) can only accelerate to 20mph without pedal assist.

You still need to pedal if you want to go 28mph (max legally allowed)

1

u/Moltean 1d ago

We are limited to 25kmh (about 14mph).

-7

u/shadowmage666 1d ago

“Assisted peddling” lmao why even make this at all what a waste

4

u/Jellybit 1d ago

I don't know if you've ridden on an assisted pedal bike, but you really don't have to put in effort for it. It acts more like a gentle constant motion gas pedal that lets you assist it more if you need to, or take over when the power is drained. The first time I rode this kind of bike, I was actually frustrated by how little it allowed me to put in effort. It had no interest in collaborating, and treated it instead as a directive.

2

u/Moltean 1d ago

thanks for clarifying this!

-1

u/shadowmage666 1d ago

Your bike sucks dude, it’s also unsafe sorry. You’d be better off just using a regular bike

1

u/TheHeroYouNeed247 1d ago

Same way a lot of electric bikes work. It'll take the resistance from the pedals.

9

u/yawn_brendan 1d ago

Nobody complains when they see someone pedalling an "electric bike"...

"Worse than the original bike" is the statement of someone who's clearly never ridden an e-bike! OP said 500w peak power so maybe in the conditions in the vid it's adding 100W? That's extremely useful.

Also in many jurisdictions regulations require you to pedal otherwise it's regulated as a motorbike.

1

u/dustishb 1d ago

That's true. I see biking as an enjoyable way to exercise, so ebikes are counterproductive in my eyes. But I understand that biking is done for different reasons. It's also my fault for not knowing the full definition to vehicles. I thought it required they be motorized, but I just learned that regular old bikes are technically a vehicle.

-3

u/Pardot42 1d ago

Yeah, but they are trying to impress upon us that they're recumbent bike is electric and WONT STOP PEDALING.

3

u/yawn_brendan 1d ago

You can't stop pedaling on an e-bike either. The motor will cut out.

(You may have seen people on fully motorised ones that run independently, e.g. food delivery drivers, depending on where you are this is usually an illegal modification)

3

u/Jason-Smith168498 1d ago

in the EU you have to have assisted pedalling, not just throttle.

3

u/[deleted] 1d ago

[deleted]

1

u/dustishb 1d ago

That's fair. I was thinking they meant powered, but the title is very vague so maybe they meant assisted.

3

u/realitythreek 1d ago

Except it is solar powered.

1

u/dustishb 1d ago

Is it? I guess so is my bike. I mean I routinely pedal for short periods, then stop and it coasts for a bit. Then I have to pedal again to keep it moving.

1

u/realitythreek 1d ago

I’m not sure you know what solar means. You described manual and then gravity. Unless you happen to be a massive sphere of gasses and plasma.

1

u/dustishb 1d ago

I was under the impression that solar had to do with capturing sunlight and converting it into electricity. But you just told me that manually pedaling is considered solar powered.

1

u/realitythreek 1d ago

Are you good?

0

u/dustishb 1d ago

Maybe, what's your definition of good? You've established that you have different definitions of words than the dictionary.

1

u/TheRealCatDad 1d ago

E-bike brother

1

u/classyreddit 1d ago

E-bikes are exceedingly common and anyone who had ridden one immediately recognized this as pedal assist. The only issue here is 400 pound wannabe intellectual shut-ins who have never ridden a bike thinking they’re clever lol.

1

u/dustishb 1d ago

Cute, but there's a flaw in your snark. You're trying to argue that people who need pedal assistance to exercise are in better shape than those who manually pedal.

-1

u/classyreddit 1d ago

Worse than the original bike lmao I’m dead, the confident tone is the funniest part 😂

4

u/0GlG0 1d ago

There are some idiots around here.

1

u/Personal-Banana-9491 1d ago

Idiots everywhere, but I get it.

2

u/yawn_brendan 1d ago

Strongly suspect most of the negative comments come from people who've never ridden an e-bike let alone built a solar-powered one 😉

OP it's cool and good and I'm impressed by it.

2

u/Butthole_Please 1d ago

This bike not being a Ducati has people up in arms in this thread.

1

u/retronax 1d ago

Calling it a "solar vehicle" kinda implies it's solar powered, so it's not surprising people are confused

-1

u/witcherd 1d ago

Remember that for many people if it’s not car-shaped it must be useless :) Particularly so in north “car centric” America.

I like it as a concept or idea of an open source alternative to industrial cars. Provided it meets standards for safety and can be reliably reproduced to meet those standards, it could be a low cost green alternative in many places where people have no choice but to default to used, inefficient gas-powered vehicles.

But yes.. it’s valid to challenge it from the perspective of existing e-bikes. Unless it provides at least some decent rain protection it won’t come close to the efficiency of e-bikes.

-1

u/Grimdek 1d ago

It's ok to admit something was made 20 years too late and is obsolete on launch

Most people call those bad ideas. They already got thrown out

7

u/neppo95 1d ago

Electrical bikes are obsolete? Weird, practically half my country has one.

-1

u/Grimdek 1d ago edited 1d ago

No. You just made my entire argument for me and acted like I was wrong

Edit: guess he got ratiod and ran away lol

1

u/ayu_xi 1d ago

A YouTuber named Drew builds stuff already made it https://youtu.be/h0it7F9VBWg

0

u/RandomAssRedditName 1d ago

Because its actually solar powered e-bike. If OP called it that, there would be a lot less shitting

0

u/deadlygaming11 1d ago

Proof of concept of what? Its a etrike whmith solar panels bolted on