Sri Lankan teenager builds solar-powered tuk-tuk from scraps [video] | Hacker News Reader

Sri Lankan teenager builds solar-powered tuk-tuk from scraps [video]

bbc.com

168 pointstagawa40 comments

That is so nice. May he have all the support he needs to build more things.

Long time back, some of my friends and college mates built a solar car [1] that we took to Australia for world solar challenge 2011. It is a 3000km race across the continent. We were very happy to see the community around the solar cars is quite strong. The same has lead to companies like LightYear[2] working on extending range of EVs with solar.

It was quite a struggle back then. Our LiFePo4 batteries got lost in shipping so we had to use 4 times heavier car gel batteries, our car had to be sawed in three sections a few days before the shipping, so we could ship in time, we got bad media coverage in Australia as we spent a few nights sleeping in the garage trying to join the sawed parts together (They kinda hinted we were poor and did not have a place to live, while we had a hostel but still had to work round the clock to make it in time as some people arrived late due to delays), and we often ran out of money as the university could only sponsor the car and not all our expenses. So, we lived on credit. When we came back, we heard foul things from people who thought we stole their funding, I had low attendance in the courses and was about to be flunked. I cried to the administration to let me sit for the exams. But we stuck together as a team. I am happy that we did it. I learned a lot.

I guess, projects like these should be encouraged. Even though the car we made was not a great one compared to the western fordian ideals of efficiency and speed, but we felt that India (and other developing countries) need representation and visibility in this domain. We built a car with whatever we had and hey! it still runs robustly. It is a bit slow, but hey! Australia is soo beautiful, we gotta take our time. We did make it to finish line without any major repairs. The cost of our entire car was equivalent to the cost of the spare motor used by one of the top teams.

I always think, there are other ways of looking at things than efficiency and speed, like initiative, frugality and the spirit of creation. There are often less stories on the second side. This story is one of them.

[1] https://www.youtube.com/watch?v=bjHEYckl8xI [2] https://lightyear.one/

Really cool project :D

Even better to see it on independence day :D

The video footage of the journey could use some stabilization.

That's quite a story. Given how much money companies like Shell and so on put into the Western universities projects (and let's not get started on the subject of the available tooling and manufacturing R&D available) I'm actually much more impressed with your entry than with the winner of that particular episode.

Props to you and your team.

In India also they build solar vehicle, the students. Most of the material is Chinese, government imposes duties on these things and Indian students are not able to afford the raw material needed to build these as a result.

Weird thing is indian government imposes duties on products that India doesn't even make.

As geopolitics, India does not want to become dependent on China.

Sure, but how you become independent if your tariffs hinder your own r&d? China seems to do it smarter by importing what needs to be imported until they can do it on their own

It's certainly something that countries should have seen coming a long time ago and have a better plan than just tariffs once it's too late. Sometimes feels like China was the only societal model that didn't allow itself to be captured by fossil fuel interests from within their own or other countries and so could react correctly to this obvious development.

China is being captured by the largest force of them all: the communist party. The party's influence has to be kept at all cost, even the economy. The current crackdown of tech companies -- Alibaba, crypto, e-tutoring -- shows that the party will not tolerate forces veering off their control.

As for fossil fuel interest, China import oil, so that's the necessary evil, and they will be happy to get rid of it the moment they can.

I don't get it. Why is the crackdown on e-tutoring bad?

I am not saying you are wrong. I do t know enough to say that. However, it is clear that we can't have a "free market" in many things, perhaps anything at all if you ask me. Too much information asymettry.

Look at India and white hat jr. There are some terrible people in this world.

Edit: you are trying to profit off of gullible parents' fear of missing out. Ed 'tech' ought to be nonprofit. You guys who are in for profit ed tech are worse than facebook.

The crackdown is not to reduce prices, the free market does that. The crackdown is to discourage/control learning western language and culture, as well as keep money from leaving the country for a service that reduces it's grip.

I wonder what a thorough comparison between the fossil fuel industry and the chinese communist party would reveal.

I can imagine a few surpises in stats around number of political opponents or inconvenient civilians killed, democratic accountability, propaganda, human rights abuses, wars started, deaths due to negligence, etc.

China has a long history of using tariffs and all sorts of regulatory tools to not only protect their industry, but export at below cost.

Adani has been making and selling solar panels in india for the last 2+ years, the duties are a late step to stop Chinese dumping that wiped out solar panel manufacturing being done by companies like moserbear in Greater Noida a decade ago.

Why would they not use old solar panels. Certainly in a country as big as India, there must be a tonne of them for students. I understand you wanted to complain about the tariffs. It's still a valid question.

reason for duties is to save foreign currency

To give some ideas of the power requirements here, a TukTuk is quite a bit heavier than a bicycle+rider, I did a 150Km trip yesterday on an e-bike, consuming about 1200 Wh of battery power and supplying the reminder the old fashioned way (using the pedals :), typically the balance is about 2/3rds pedal power and 1/3rd motor unless going uphill.

1200 Wh would require a surface of about 4 square meters of panels for an hour in direct sunlight. Let's multiply that by three or so for this TukTuk on account of the weight difference and much larger frontal area as well as the much wider 3 wheels and you can get an idea of how much duty cycle you can get out of this setup. This could be improved by adding a wall socket charger but then it isn't really solar powered anymore, at best it would be solar augmented.

Useful calculator for bicycle power consumption:

https://www.tribology-abc.com/calculators/cycling.htm

This seems like a market niche that is going to grow very rapidly as it passes a tipping point.

I look forward to the repeat of hearing about Africans paying for things with their mobile phones and thinking, wow, that sounds like the future. But this time it will be low pollution urban areas near the equator where renewable powered electric transport is the rule, not the exception.

How liquid is the market for second hand PV? If half a panel is damaged does it make economic sense to ship it to a poorer but sunnier location where it can be repurposed even if it doesn't meet the needs of the original owner? The second hand EV battery market seems fairly robust even at its current small size.

The future is now.

https://www.forbes.com/sites/ilonalimonta-volkova/2020/12/07...

There are lot of teenagers and young inventors who can do great things in Sri Lanka

However, the lack of a good startup ecosystem and education system not willing to support hem, they don’t make it beyond these articles.

I was amazed by the story of William Kamkwamba.

https://en.m.wikipedia.org/wiki/William_Kamkwamba

Having been a couple of times outside of our cozy Europe in African and South American countries, I am always amazed how people make do with what they have.

And in a similar note, how much they could actually have if instead war and exploitation, they were able to explore the countries resources.

That's impressive. Building a wind turbine that generates usable power from scrap parts without access to a lot of documentation and a good workshop is pretty difficult. Love that tower too, it's so nicely made.

I watched the Netflix movie adaptation "The Boy Who Harnessed the Wind" with my children. It's a very inspiring story, and in some ways humbling to see someone needing to fight every step of the way for education, a better life, and survival.

Kids building clocks and tuk-tuks while I still struggle to center that div.

Relatedly, just imagine if the entire world's population could enjoy the privileges most of us HNers generally take for granted. Access to free (higher) education, internet, higher paid/skilled job market, cheap hardware, et al. I would guess at minimum a ten-fold increase globally of engineers, IT-experts, scientists, etc. who could contribute their knowledge and skills, thereby potentially benefiting everyone on Earth.

Having the solar cells on the side looks like a wrong design. But let's assume there is some on the roof. 1sqm of panel in Sri Lanka shd generate 150 Watts during clear day, according to one source you need 6.8kwh (which sounds too high for me) for 20km im urban area, 44hours of charging. 2sqm 22 hours.

If the panels catch some light while it is moving it might make for a good assist, 150 watts extra is nothing to sneeze at with a pedal powered vehicle. When I'm cycling longer distances I can sustain 80-125 watts for 3 hours or so, which is definitely not athlete material but pretty decent for an old guy with a gimp leg ;)

Going uphill that would make a huge difference (especially because a Tuk-Tuk is quite heavy), more so if you can store the power when you don't need it and dump it all in one go when you're going uphill, but then you'd need to have a battery in the system.

Is the device in the article pedal powered?

Hm, good point, I can't find any drive train components at all when playing the video frame-by-frame.

Neither motor nor pedals & chain, unless he's using a hub motor in the front?

Edit: just found this: https://electricalconnection.com.au/the-future-of-electric-v...

Which makes me wonder how viable this particular reincarnation of the concept is. They have far more panels, have them facing up (which is good), have a much more efficient battery and still need a socket to charge up the battery because there isn't enough power from the panels.

Edit2: I noticed all of the panels except for the 'door' have hinges at the top, I suspect they are placed horizontal for charging purposes. If not augmented by another power source then I suspect it has a very low duty cycle.

It generates viable publicity.

i own an electric scooter which is a 250 Watt motor and has a 48V 24Ah battery so 1KWH. this gives me about 50 Km for one charge. on this scooter, i put over 220 KG of load and it runs so there should be no problems putting two of those motors in a three wheel design. about power, i am sure this is just for "topping up" the battery because one can have a battery bank at home which charges from sun which can be swapped for next day. that way you can put even a 330 watt panel and that should charge this system during the entire day. then you have to account for cloudy days and such so maybe bump the solar up so if you put something like 500 Watts or more with a second battery pack of 2+ Kwh, that should be comfortable

In good dry Norwegian summer weather, at a steady 90 kph on the flat, my 2015 Model S 70D will consume about 170 Wh/km, that's 3.4 kWh for 20 km. So 6.8 kWh for urban driving with what is probably a much less efficient drive train sounds a bit high but not wildly off.

Google tells me your car weighs 2090kg/4647 pounds. This tuk tuk probably weighs a tenth of that. Add passengers, and you probably are still looking at a factor of 5.

Also, I don’t think 90kph is a realistic cruising speed for this tuk tuk. Assuming 22kph, that’s a factor of 16 in air resistance.

The Tesla wins on a aerodynamics, though, and rolling resistance could be lower for a Tesla/US road than this tuk tuk/Sri Lankan road.

Overall, I would guess you would need a factor of 10 or so to compare the two vehicles (but that’s a wild guess/gut feeling. If humans had 8 or 12 fingers, chances were my guess would be 8 respectively 12).

You are right of course about the tuk-tuk not cruising at 90 kph. I used that because consumption at that speed is about the only figure I can be confident of regarding the Tesla; it's hard to find a road where I can travel the requisite 10 km at 22 kph to get a good consumption reading. Perhaps I'll give it a try if I can find a place to do it, I read somewhere that someone did an economy run in a Model S and got a thousand km range at something like 30 kph.

I think that the Tesla probably benefits from an economy of scale both in manufacturing volume and advanced motor and inverter design.

According to our favourite search engine tuk-tuks weigh between 250 and 450 kg so with driver and passenger the smaller ones are about one sixth the mass of my car, the bigger ones a bit over a quarter.

The small motor in the tuk-tuk is probably much less efficient than the Tesla motor even in the middle of its power range. Also I doubt that the tuk-tuk would have especially effective regenerative breaking because doing this automatically requires coordination with the mechanical brakes. I'm pretty confident that no vehicle in the tuk-tuk weight class other than some specially designed research vehicle will travel a kilometre on only 17 Whr, certainly not one carrying passengers. The losses will be dominated by rolling resistance. Or did I misinterpret your factor of ten?

For comparison an electric scooter with a 36 V, 7.5 Ah battery has a range of 25 km, that's 10.8 Wh/km. See https://stayclassy.no/collections/el-sparkesykkel/products/c...

Anyway, none of this is meant to detract from the achievement of the guy with the solar powered tuk-tuk.

P.s. not that it makes any real difference but the roads are Norwegian not US. :-)

out of direct sunlight, solar panels can produce a 3rd of their max output from ambient. This is only during the day.

Ambient light however, cannot travel even a km, as soon as the sun stops hitting that part of the earth, the output drops to zero.

This is despite the human eye being able to see.

Why not put them on the homes roof and get 3 times more harvest.

Because the math doesn't work out, see my other comment.

That's a misinterpretation of the data.

The incident radiation is on the order of 100 W / square meter (10K Lux max, and probably much less depending on local conditions) from ambient (versus about 1KW / square meter for direct sunlight, 120K Lux), the panels then extract about 10% of that, so 10 W give or take for a panel area that would produce 250 to 300W when exposed to full sunlight.

Ambient light tends to be reflected more than direct sunlight due to the percentage of the photons arriving at an angle < 45 degrees relative to the plane, which means they'll very likely bounce off.

This is why it isn't cost effective to put solar panels facing North on a roof, and panels facing East or West will only be producing power for a small part of the day.

If you've got a pile of solar cells sitting around you might as well use them to make the doors too.

I agree, though, that even if it only draws 500W then this thing is only going to be driving for a few minutes a day on that amount of panels.

Cool scooter for a highschool kid though!

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