How far can I go on my solar powered bike?

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I try to cycle to 200km to London using my Ridgeback electric bike, towing a solar panel behind me to charge the battery. Along the way things don't exactly go as planned, and I learn some lessons about low carbon transport.
Previous video on my e-bike: • Are e-bikes worth it?
Video on decarbonising transport: • How to decarbonise tra...
Equipment used:
- Mobisun panel 100W / 18V
- Mobisun Pro | Portable solar generator, 70,000 mAh
- Ridgeback Arcus 1
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Music by Epidemic Sound: epidemicsound.com
Some stock footage courtesy of Getty.
Edited by Luke Negus.
How far can you go on an electric bike? I attach a solar panel to my e-bike and find out! I try to cycle from Bath to London and learn lessons about the scientific method, how to run an experiment, assumptions, and come to a realisation about low carbon transport.
Huge thanks to my supporters on Patreon: Felix Winkler, CC, Rebecca Rivers, Thomas Charbonnel, Mark Moore, Philipp Legner, Zoey O'Neill, Veronica Castello-Vooght, Heijde, Paul H and Linda L, Marcus Bosshard, Liat Khitman, Dan Sherman, Matthew Powell, Adrian Sand, Stormchaser007 , Dan Nelson, The Cairene on Caffeine, Cody VanZandt, Igor Francetic, bitreign33 , Thusto , Andy Hartley, Lachlan Woods, Andrea De Mezzo.
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[@myownsite]

If it generated 100W the new output is conveniently half, and it seems to have two distinct modules. Maybe one of them got disconnected in the rattling. I’d do the output test again and seeing what kind of an effect covering half of it has.

[@NinjaWatermelon42]

This seems the most plausible explanation to me

[@ElectricityTaster]

The possibility of rattling breaking the panels proves how bad an idea this is. Just take two charged batteries and have your mom keep two charged batteries for the way back. No reason why we can't have a standard bicycle battery and swap them out at the post office like some people do with gas canisters (obviously not at the post office).

[@myownsite]

@@ElectricityTaster just wrong kind of panel for the job, it's possible to have wiring which handles that.

[@TemplarOnHigh]

​@@myownsiteCorrect. RVs commonly have modules which are hardened for vehicular application. I (person who has been doing PV for over a decade) also wonder what the impact of shade is on the charge rate. If he was zipping through trees on the trail, the charge controller could have had a very hard time getting much juice back into the battery. Once he hit a main road, he got a lot more SoC per hour, suggesting the shade had something to do with it.

[@mozismobile]

Just as likely rattling those "flexible" panels destroyed them. They're still made of rigid crystals, thin ones, and it's more useful to think of them as "slightly flexible, once" panels - glue them to a curved surface and you're fine, use them as a wobble board and they'll generate just as much electricity as a wobble board.

[@TerrifiedRat]

Yes, you could spend thousands of dollars on an eBike kzbin.infoUgkxUiL0GnyDjP32RJdd660sP8mZk4CRLTCJ and get something much higher quality. However, if you're looking for a basic model to try out eBiking this is a great choice. The assembly is easy as far as bikes go (took about an hour for me to do, I'm not an expert). All tools needed are included. I added the plastic mud guards you see and a more comfortable seat. The other reviews are correct that you're probably going to want a better seat (Giddy Up! Bike Seat is what I got - super comfortable). The battery easily handles a 2-4 hour ride if you add some of your own pedal power. I haven't even gotten it up to top speed yet - it is very fast. Components are not top of the line, but decent for the price and work just fine. It works great on dirt roads and singletrack and pavement although too heavy to do tricks or any serious technical mountain biking. I'm looking forward to using it a lot over the summer. Tons of fun!

[@alexhofvander]

I have been doing solar powered e-biking for 4 years now. Last trip I did was 251km in one day. 50% battery left out of a 1100wh pack. Charging and using the same battery. I have a high quality 160w panel on a single wheel trailer. Boost charge controller. I had fun watching your experiment but I guess you need to do it again.

[@CrusterfunkShenanigans]

that is awesome, do you frequent any fora on this subject I should be aware of? I am in the process of planning a trip to the black sea from the Netherlands on my electric bakfiets ;)

[@michaelpoier5699]

Hi Alex, which type of Charger do you use? Michael

[@alexhofvander]

@@michaelpoier5699 hi. Boost charger that take the lower voltage from the solar panel and boost it up to the correct charging voltage for the battery. I only use Genasun. There are no real alternatives unfortunately unless you go cheap and buy the Chinese options that does not perform nearly as well. Genasun are over priced in my opinion but the best.

[@k1zmt]

Could you please make a video about your bikes and their design. It would be nice learn about them.

[@alexhofvander]

@@k1zmt there already is a good video explaining pretty much exactly what I have been doing. Me personally. I use the motor only when I really need to. Uphills and when get going. Using this approach and mindset “flattens” out the ride and you save your own energy for the easy pedalling. Using this method I can travel further than normal and solar can keep the battery happy. kzbin.info/www/bejne/Z2XcnZyNod6enMksi=fNHVGASytcJqODJo

[@zoefschildpad]

I think the way to get this to work is by using an electric (if that exists) streamlined recumbent bicycle and covering it in solar panels. That way you start with a more efficient bike to begin with and you can add solar panels on the body which, if you do it right, wouldn't impact the friction that much. You would melt into a puddle in it, though.

[@Cyrathil]

A recumbent bike might make the lack of wide paths even worse. The trailer he was pulling was giving him issues and a recumbent bike is going to be at least as wide.

[@mozismobile]

the solar race cars in Australia used to have a second category for pedal assist bikes. But experiments here have shown that the way to make it work properly is indeed a trailer with solar panels, you just need a bigger trailer (and use wider roads). There's also a lot of skill in designing a system that copes well with partial shading, especially rapidly changing partial shading.

[@dwizzyvid]

I had a recumbent that was about as wide as a regular bike, more agile than this setup with trailer. Still not great on rough terrain as you're less able to shift weight with your body. But taking rough terrain really asks more energy to begin with. There are experiments around with solar velomobiles, the 'capsule' recumbent bikes.

[@Abel_DG]

Or just buy a “velomobiel”. That’s a very streamlined bike which can easily do 45 kmh. WITHOUT A MOTOR!

[@aenorist2431]

Such things do exist, they do not solve a fraction of the problems. This cannot work until we have vastly more efficient solar or reduce the power draw to an insignificant degree, making it moot. Tldr just bike.

[@huw3945]

Now you need to do the same route without the trailer and see if you could get as far on one battery without the drag from the trailer

[@Septimus_ii]

I don't think he'd get much futher than he did on the first battery - the motor output is mostly fixed and it's up to the rider to put in any extra effort required. I think a better test is to try with the motor turned down to 100W (which is probably enough to get to London) and then a standard road bike (which is also enough to get to London) and see which is easier. Does the 100W cover the extra effort needed to pull the trailer?

[@filipvidinovski7960]

Have you ever ridden a bike with a lightly loaded/empty trailer? The difference in the effort needed is negligible.

[@huw3945]

@@filipvidinovski7960 yes, but he says in the video how he kept having issues with the trailer on the narrow paths that he wouldn’t have had with just the bike. I meant the drag of it on the bad terrain and grass and the break going on, not just the weight and tires

[@alexanderhetzel8271]

I'd guess he would probably be better off without the trailer. I could easily get 100km on my ebike (same european limits on power etc.) with low support on one battery, with that rough narrow path that trailer probably used up a lot of power. And remember, if you go 25 km/h, your power usage quickly drops to zero.

[@AP-cc5ym]

This video raised so many questions for me for how it could be pulled off, like if he just took 3 charged batteries and left the whole trailer etc behind he could probably make it especially if he found a plug to charge a bit while he ate lunch.

[@melindaleon5907]

This panel can put out close to 100 watts kzbin.infoUgkxOqI2yqX0XVrhR2BMJciTWrHJpG8FhJyg when positioned in the appropriate southernly direction, tilted to the optimal angle for your latitude/date, and connected to a higher capacity device than a 500. The built in kickstand angle is a fixed at 50 degrees. Up to 20% more power can be output by selecting the actual date and latitude optimal angle.The 500 will only input 3.5A maximum at 18 volts for 63 watts. Some of the excess power from the panel can be fed into a USB battery bank, charged directly from the panel while also charging a 500. This will allow you to harvest as much as 63 + 15 = 78 watts.If this panel is used to charge a larger device, such as the power station, then its full output potential can be realized.

[@philzoff1647]

Maybe the heat reduced the panel efficiency? It tends to have this kind of effect on batteries

[@alexanderdaum8053]

Yes, panel heat reduces efficiency. According to Wikipedia: "An increase in solar cell temperature of approximately 1 °C causes an efficiency decrease of about 0.45%."

[@nonsequitor]

Yes, a bit , but by far the biggest problem is that solar panels only capture a small percentage of solar energy. A relatively low powered bike will use many hundreds of Watts. A solar panel that size will make one hundred in ideal conditions. That's why solar powered vehicles are ultra streamlined and covered in cells.

[@Beeeeeeeeeee]

​@@alexanderdaum8053but even a single cell on the panels shaded, will easily half the output. Heat really isn't as much an issue, else there wouldn't be panels flat mounted on roofs.

[@alexanderdaum8053]

​@@Beeeeeeeeeee Yes, when the cells are connected in series (most are), shading a part of the panel will make a huge difference. That also applies to multiple panels connected in series. However, temperature can still have a significant impact (although far less than 50%). Tech Ingredients ran a test on this (kzbin.info/www/bejne/g6Wcon-Ig5x9rKM). With some cooling at ~40°C the panel produced 63,4W. Without cooling at 53°C it produced 58,7W. That's a 7,4% efficiency loss from just 13°C temperature difference. The problem is just, that panels aren't that expensive, and installing them with cooling would be much more expensive than just adding a few more panels.

[@AlRoderick]

They do make panels with cooling and it's actually extremely practical to do so, because the heat you extract from the panels can be used to do something else. It's called a PVT panel combined photovoltaic and thermal. You run either plain water or an antifreeze-based coolant through tubes mounted to the back of the photovoltaic panel and then you use that heat to do something like heating a swimming pool. You do have to use some of the generated electricity to run the circulator pump for the coolant, but in general it covers its own costs.

[@tvuser9529]

Great video! Solar powered ebikes have been done very successfully. The Sun Trip is a solar powered ebike race. Next year's race is 7000 km long. They tend to use bigger panels than you've got. I read of one case using a recumbent trike with a solar roof, and a trailer with more panels. They could do something like 30+ km/h at mid day while _increasing_ their total battery charge, so they had juice left for after sunset. With enough panels and batteries, you could keep going 24/7 until collapsing from lack of sleep. Even in overcast and rain you get some power from the panels. I've been interested in trying this myself. But to account for all the factors you describe so well, I'd be looking at something like 400 watts of solar panels for a 250 watt EU pedelec, which would require a very big trailer, like 1 m wide and 2 m long, the size of a bed. It would be both heavy and vulnerable to wind, and should probably have suspension. I'd have to build it myself, and bike paths would usually be out of the question, due to barriers and concern for other path users. I have done long tours on unmotorised bikes. The solar assist would make the hills easier, but the trailer would hamper the ride a lot, like you experienced. Parking also becomes an issue, and you'd be more vulnerable to technical problems. I'm not sure it's worth it for me. Maybe when I get older. The Sun Trip: www.thesuntrip.com/en/

[@ahaveland]

I followed youtuber Jack Butler on his Sun Trip ride to China 4 years ago - amazing. I think the width restriction for a bike trailer is 80cm, so I guess you would need to make your own panels. I made my own using A3 size foamboard for lightness, with sunpower cells and it was very time consuming and delicate work! I made 4 x 100 W 36-cell panels, (144 cells, 6 x A3 x 4) and they weigh about 1.1kg each. I carry them in panniers or a backpack because they aren't very waterproof though it would be good to find a way of mounting them. However, they are easy to set up for a quick charge. I think Simon needs to learn about the amazing machines that people have built for Sun Trip!

[@purplepenguin43]

I've always wanted someone to do a suntrip setup where they charge during the day and then pack up into a aerodynamic recubant and only ride at night. it will probably never happened for safety reasons but I think It could be a very fast strategy.

[@ahaveland]

@@purplepenguin43 No time for sleep? If you're not moving when charging, then you have to go much faster to catch up.

[@pascalj4331]

@@purplepenguin43 and/or take naps from 10 to 2 during day.

[@JackButlerVideos]

@@ahaveland Thanks for the mention ;)

[@applegateoutdoorsadventures]

You may have much better results using a higher quality sunpower or renogy panel with genasun or victron mppt controller tuned to your battery's max input current and connected for direct DC charging. Some of the cheaper controllers will delay supplying any power to the battery for as much as a couple minutes after going through shade and returning to sun so this may have been a factor. If you were using a inverter with the bike's AC charger that would have also taken a big toll on efficiency which should have been taken into account in your calculations.

[@CrusterfunkShenanigans]

I am currently working on my electric cargo tricycle, going to make it into a little teardrop camper covered in solar so I can travel Europe with my doggy, so this video was timed right for me and I enjoyed it a lot but most of all I got some really handy pointers to take into consideration, Greetings from the Netherlands!

[@JK-zl7vv]

If your planning on using solar as your charge source, your plan of route should be the one that has the most sunlight, it looks like the bike path you took, is 80% shade, so a route on the roadway looks like it would have been a better choice. 😁👍

[@ScrapKing73]

In a moment where you stopped for lunch and were surprised the panel wasn’t producing much, a wheel was casting a shadow on the panel. A one-wheeled trailer might have been a better choice.

[@GabrielPettier]

12:16, since this is suspiciously close to 50% of the power, i would try to block each half of the panel to see if it makes a difference, maybe one connection got broke and half the cells are disconnected. edit: just saw you answered to that theory already, weird that it's not the case.

[@MyKharli]

A battery bashing experiment , i use two 48v 28.8 ah triangle upp batteries that fit in panniers perfectly, for long distances . If i take trailer i put another spare one in that . I adapted the trailer you got and put on 26" wheels and used a fish crate , super tough and way less bouncy,,also handy spare wheels in an emergency .

[@k.herzog2365]

Got so much more than I expected. Great video, cheers :D Especially liked that you wove information on how to test hypotheses into the whole thing

[@LucasCarter2]

I think having the panel attached to your backpack would give you some amount of charge without being in the way. Additionally just having the panel with you let’s you charge throughout the day so technically speaking so long as you have food and water the bike should take you anywhere the land allows you too.

[@jimbo92107]

1. Build your system on a recumbent bike with a windshield and a flat roof. 2. Put solar panels on the roof, plus the trailer. 3. Put reflecting mirrors around your solar panels. This will reduce your wind drag, be more comfortable to pedal, and more than double your solar input.

[@utubeape]

Yes, and giving the rider shade will decrease fatigue. Possibly have the roof able to be tilted to angle in to the sun too

[@alankemp1970]

It’s fun to experiment. My self build electric ebike has 125-140 mile range running on its 14 cell 42ah (2.5kwh) battery pack built using cells from a Nissan Leaf electric car, charging in 45 minutes with a 30amp charger (I have an adapter to use public electric vehicle charge points. Solar is great but you need two 345w panels (so 3 X 2m surface area) to get any benefits from it. I converted my sail boat to electric drive and this solar set up as a canopy works well when sailing for the day replacing the 15% we use from the 5kwh 48v battery in good weather.

[@AlRoderick]

If you wanted to repeat this experiment you could get a hold of or rent an electric cargo bike like a bakfiets, rather than riding with the draggy trailer, you could mount the solar panel over the cargo box like a lid with some method of angling it one way or the other to point south. Get a hold of a rigid panel the generates about 200 watts instead of your little floppy one. Using the cargo bike is a good move because the load will be in front of you and watch what it's going to snag on as you go.

[@stephoh8613]

I've had the same idea before, though never got to the experience because my calculations were basically pointing to the fact that for the extra weight (and cost) of a solar panel, you are better off grabing 2-3 extra batteries to go further. I once did 90 km on a single battery (though I was dead tired at the end of that), so with a few batteries that journey to London would be a breeze!

[@Oli-l5m]

Love this video! Fantastic example of the difference between theory and practice. As an engineer, I see this all the time and sometimes, experience is the only way to learn your conclusions.

[@maxedoughty]

Ahh you were in BOA! :) I've cycled from there to Bath and the terrain really isn't great! I arrived in Bath exhausted not because of the distance, but because of being constantly shaken by the towpath. I think this video helps show the importance of decent infrastructure for active travel though! Towpaths really shouldn't be used as an excuse for councils to not build proper cycling infrastructure due to their terrain, width and lack of decent lighting

[@grantandeviesplace681]

Great video, and it’s amazing to see a failed experiment given so much attention. I would also add the power loss between the act of charging and discharging. The solar power might generate 100w but only 80w will be actually stored and then of the 80w only 60w will be used to power the wheel (for example) I believe it’s called charging loss

[@joey_f4ke238]

Damn those are some huge power losses, i would realistically expect the charge controller to be in the high 90's efficiency so maybe a max of 10% power lost, not 40%

[@Tim_Small]

Micro cracks in the photo cells (see video "Invisible damage from walking on a solar panel" from NREL which take advantage of the fact that solar cells act as near infrared LEDs when they have a voltage applied to them). Also I noticed some shading from some fabric @3:41 which can be significant depending on panel internal configuration.

[@janalu4067]

There are some great one-wheeled trailers for cargo transport. Just wanted to tell you that. Thank you though! This is good info when considering cargo bikes for child transport and child carrier trailers. I knew 2 wheels side-by-side was harder for snow, but you have exposed several other factors. Thanks ❤

[@cameronveale7768]

That's great ! Thought of doing the same with my ebike , but for the same issues decided on restricting range to two batteries here in rural ontario. With a road choice of highway or gravel back roads, a trailer is only for short rides. E bikes a fantastic piece of kit for those short 10-15K trips though out here. Wish i had one when biking in downtown Toronto dodging dump trucks and taxis. cheers

[@ZirothTech]

Glad to see my hometown Pewsey's station getting back on the big screen after it's crowning moment at the start of The Lion, the Witch and the Wardrobe

[@CaptainBlitz]

We actually did something like this for our senior project... it also failed lol. I think given advances in battery technology, and probably lighter batteries, we could soon have e-bikes that could go medium to long distances without needing to be charged much on the road.

[@znail4675]

It's already here. I got a bike that should manage that distance with a battery swap.

[@rickhurst9058]

The output of these solar panels really does vary - I have a similar portable 200 watt panel (good luck getting that on a bike trailer!) and the output varies by the minute between 20 watts and 160 watt+ depending on cloud etc., and meticulously moving it to point towards the sun. I can't imagine there was much output from that panel in and out of shade, different angles etc. - enough to charge a phone maybe!

[@billmmckelvie5188]

Thank you for this video it is a brave thing to set off on this long journey with an electric bike where others would use a road bike. One thing you have forgotten is you have two wheels with a dynamo attached to each, you generate 10W of power at 6V. If I was approaching this subject and after watching your video, I would be starting with three fully charged batteries.

[@ginavong401]

This was an excellent exposition of the scientific method!

[@hananas2]

I've always wondered how much it would help to put a solar panel on an electric cargo bike like a Bullitt since they wouldn't suffer from extra drag from a trailer, just a little more weight.

[@bvgb921]

I have a trailer also, I have 3X17ah battery's and a small 700 watt petrol generator, I know it's sort of defeating the object but it works great, doesn't matter if it's over cast, I can charge while I ride and the generator is actually lighter that a 100 watt solar panel.

[@IraQNid]

There are two places in the USA called Middle and Nowhere. For an experimenter I'd have figured you'd have used a cargo net over the back of the trailer to keep stuff from falling out, to bring along a multi-meter to test things with, and would have known that folding flexible panels aren't ideal for many uses. Plus a light meter could have been used to record when you were in different lighting conditions, for how long, etc. Cuts out the guess work for solid results.

[@zwe1l1nkehaende]

Maybe i missed it, but did you take charging/discharging efficiency into account? Putting 100Wh of power generation via the solar panels into a battery wont result in the battery delivering 100 Wh to your bike. So you probably have another 0.5 factor you would have to account for. I know a few people that have those ultra low drag bikes you lie down in. Equipping one of those with a battery, electric motor and a solar panel could actually make a big difference and there it could actually be viable.

[@MichaelEricMenk]

You do get MPPT boost charge controllers intended to charge a bike while riding. One bike in a KZbin video had a beam connected above the back wheel, with one solar pannel on each side connected in parallel...

[@Konsul135]

A failed experiment is still a failed experiment (or can an experiment ever truly fail?)! I have never used an electric bike (my city is so flat and small enough that I just walk everywhere) but this just showed me again that they would be great for a hilly city and those short 15-20 min (by bike) commutes that tend to get a bit tedious on foot if you have to do them every day.

[@robinbennett5994]

Those folding panels are quite well known for breaking when abused. I suspect all the bumps broke many of the cells, which is why you're only getting 45W from a 100W panel. BTW, were you able to charge your bike from the mains sockets on the train? IIRC, the UK was 30-40% solar powered during those sunny days, so that would sort-of count ;-)

[@ahaveland]

That panel was far too small to generate 100W. Maybe it could do it in the vicinity of Venus! Area doesn't lie.

[@PinnysVids]

As a dutchy, I cycle to work on an ebike. Across flat terrain, on good roads on days with out wind, and on the lowest setting (which is my normal setting), my battery says it can do 120km. With some headwind half the time, I find that I need to recharge about once per 8 or 9 days, which is 11km * 8 = 88 kilometers. The battery is never empty by then, maybe 20-30%. Long story short: I thought you could really make it to London, until I saw the road condition & your battery drain over time. I bet you could make it in the Netherlands

[@trevinbeattie4888]

Having done several long-distance rides on my road bike (plus a 46k ride this morning), my biggest concern with you doing a 200k was not the battery but making sure you yourself don’t get too exhausted, dehydrated, or sunburned.

[@SimonClark]

Honestly I think I overpacked on food and water!

[@BlacqueJacqueShellacque_]

I'm planning a trip like this. 120 miles. I will have 2 fully charged batteries for my bike (500wh each). I've gotten up to about 50 miles out of a single battery before, but I will plan on getting less to be on the safe side. I will also have a 700wh battery bank and a 200W solar panel connected to it. So should be no problem. When the first battery dies I'll plug it into the battery bank, which will provide a quick charge to that battery (about 3 hours to get to 100%), while the solar panels (hopefully) keep the battery bank close to full. I will do some shorter tests first.

[@jameshughes3014]

I love seeing these kinds of things. I'm thinking more efficient panels, more of them (maybe a canopy), and a dedicated MPPT DC to DC charger fine tuned for this would really be required to make this useful.

[@TAmateurGuy]

doesn’t work on such a small platform, it would only increase dead weight.

[@jameshughes3014]

@@TAmateurGuyYou're probably right, but I think with lightweight panels, a canopy, and a dedicated MPPT, you could get a kilowatt hour of power per day that it sits in the sun. The real question is, if you did build a sort of extremely lightweight aerodynamic canopy and use flexible panels and aluminum how much would it reduce the efficiency of the bike? because on a normal ebike, that would be about 3 miles of extra range a day. But if it adds too much drag, you're right that it would come out negative. Still, I feel we're at a place where this is becoming a possibility, and with careful engineering, I believe it could be useful today. I'd like to be able to charge my bike by leaving it out in the sun for a few days.

[@jameshughes3014]

@@TAmateurGuyOh, I double checked my math, I was way off, that's the range for cars. On an e-bike, 1kwh would get you something like 60 miles . So, even with reduced efficiency, It seems it would be very useful.

[@TAmateurGuy]

@@jameshughes3014 Thanks for taking the time and checking it. I really haven’t worked on any similar projects, mostly did research on large scale PV system controls but this is really interesting and I would have tried to build something from ground up if I could find the time. Did you account the extra weight? I’m not sure about torque produced in this platform. Did you you account the non consistent radiation lvl and angle as well? I would propose building it on a platform with variable angle for extra efficiency but it really comes down to amount of weight we can tolerate. But generally bikes don’t offer the surface area required to produce enough electricity, and even cars have trouble producing enough power. Again thanks for replying and have a great day.

[@jameshughes3014]

@@TAmateurGuy that's the question, but even if range was cut in half, and you could only realistically pull 750 watt hours a day, that's an extra 12 miles of range easy. However I just watched a video where a guy did just that, and he was able to ride at 6mph with no battery at all. The weight didn't seem bad. They do make light weight panels, you just have to give up some efficiency. So I think it is doable

[@theunknownunknowns5168]

Simon, flexible solar panels are notorious for failures. They are cheap for a reason. Also, depending on the way they are wired, even a small shadow over a small section can cut electricity generation to a large section or all of the panel. The experiment had some... major design flaws.

[@SimonClark]

almost like I made a whole video about that fact

[@user-xsn5ozskwg]

That was super neat to see! I kinda figured it wouldn't wok out but didn't expect it to fall so short, or to be because of the extra weight, drag, and difficult terrain. I really wish we had the rail systems and infrastructure in the US to make a similar experiment possible.

[@migrantfamily]

There’s one category of loss that you omitted, loss associated with charging and discharging. And if you really want to succeed in getting all the way to London, there’s a lot you can do to optimise your system. The easiest would be to ditch the electric assist altogether. But other than that, a more efficient bike (road/gravel style), a more streamlined trailer, preferably single wheel for towpaths - or just use the roads.

[@martydouglas1802]

You were on the right track as the system was not regenerative and the solar panels were weaker than obtainable these days. This was a good experiment that needs work to succeed. My hats off to you mate.

[@tvuser9529]

Devizes, famous for being the place where the device was first invented. Now, devices are all over the world. An amazing success story. Similar is also true for Bath, of course.

[@Peter_739]

I was kinda expecting the panel to not charge all that much from the get go, the thing that really surprised me was your first battery being gone after 35 km. I ride a budget Decathlon bike (420Wh battery) and in very hilly Slovak terrain I get at least 50 KMs, I did a few 80+ km trips (admittedly while being very power conservative). btw I do appreciate the Mitchell and Webb joke.

[@danielwalls5150]

I’m wondering how much charge your battery can accept. For example, your panel was generating 20w but the battery might have only accepted 5. Fixing that would need a third battery so 2 charge simultaneously.

[@CianFDowd]

Getting to Pewsey felt like something out of a Top Gear viseo. Great moment!

[@dperreno]

Some have speculated that perhaps only half of your array was working due to a broken connection due to the vibrations from the rough path, others have speculated that the array only ever was capable of 50W in spite of the "advertised" output. I tend to agree with the latter. Also, dragging that trailer behind you really increases the amount of work required, and hence power draw. I would say it easily doubled the amount of power required.

[@badrinair]

might be 2 100w panel in a tent like set up , might give the battery more juice. 50% of that will be 100 watts. Just as I was typing this, a tent like set up will always expose only one panel to sun and the other will always be in shade. Scratch this suggestion. might be a second panel within the A frame , but it will be smaller.

[@bramscheurwater1995]

Great video Simon! I may have another explanation for your disappointing solar output. When a manufacturer claims 100Wp output, they mean at 1000W/m2 irradiance (standard test conditions). This is the amount of sunlight reaching the earth when the sky is perfectly clear. In the UK these conditions will never be met in real life because the atmosphere absorbs more irradiance (due to the earth tilt). SolarAtlas shows that in the UK on an average day in July about 300 W/m2 reaches the ground (at noon). On this particularly good day it may have been 600w/m2. If we scale the electrical output linearly with the irradiance the panels should output about 60W. Hope this helps!

[@chrisvilavelha]

Simon, good video thank you. What was the voltage and amperage, (Ah), of the batteries that you used ? and the voltage of your hub-motor (geared?) The weight of the loaded trailer would also be useful. I am building a cargo bike for a much longer trip I was going to do it without a hub-motor but at my advanced age I think the uphill sections might prove to be an overload to my legs. I intend to pull a trailer with a 1KW petrol generator that has an out put of 8amps at 12V, so I should be able to charge my 3 12v batteries for my 350w. hub. Thanks, Chris.

[@ReviewsandTech]

Very interesting idea as I own a very similar solar panel myself. Thank you for sharing this with the community too. Although i would say that its hard to find a solar panel that will give you 100% output even on sunny days.

[@TheHDreality]

Instead of a trailer, which adds a lot of weight and friction, you should try mounting the panel flat to an extended pannier on the back of the bike, basically no extra weight or friction and you can still use pannier bags either side of it. Also if you can make it clip onto the panniers it could be detachable so you can take your bike on the train more easily

[@dr.ahmedjabbar265]

There is another important factor you did not take it into consideration, which is partial shading.. the yellow thing was covering part of the PV cell and drop all the panel efficiency.. since the panel had many cells in series.

[@gunlover1955]

Get one bifacial panel and mount it vertical on a trailer so it can make power all the time they make some really good panels now that make power from both sides.

[@thepandaman]

I had been musing over this, and figured that if you're rich enough the simplest solution is just to have multiple fully charged batteries at the outset. Plus an e-bike designed for longer distances, like the Cannondale synapse. As for the whole "just take a train"...yeah, my nearest station is 35 miles away. Joys of rural living!

[@kingarthurthe5th]

You should look into getting a solar irradiance meter so that you know how intense the sunlight is when measuring the solar panel wattage and efficiency.

[@g0dzilla5]

Dunno how the algorithm will take it but I like this kind of irl content + storytelling + educational value as a complement to the usual voice over stuff. It’s fun and I hope it does well enough to merit more similar videos.

[@Kosahdus]

Solar panels output power degrades by temperature rise. Nominal 100w is when panel is only 25 C surface temperature. You should measure the panel temperature and check the manufacturer curve for power output by temperature.

[@TimpBizkit]

I tried charging using a big 20V panel, a DC-DC converter to convert to 54.6V and an xlr cable to charge. I had a fault with the panel I think one of the cells got damaged or bent so I returned it. My plan was to extend the back of the bike frame with a big wooden triangle to have it straight out behind me. I was finding I was only getting about 20 watts. Perhaps I need a hotter country.

[@hampopper3150]

you need to make a proper solar trailer that has one wheel and allows the panel to tilt automatically with the sun. also gear hub motors are for low speed like hill climbing and accelerating from a stop after that you peddle the rest of the way. You can have a 2nd hub motor for the speed after the geared motor gets you to speed.

[@JacobBax]

On twitch, there is a streamer called "Hitch" he is cycling from Belgium to the North Kapp with a 200W solar panel made by "Yverr", (also a twitch streamer) for powering his stream, not the bike. So far he hasn't used a wall socket to charge his batteries. The solar panel was made for an ebike race, also without using external power but only sunlight.

[@EpicHardware]

i build a electric bike with the bafang bbshd and 2 x 48v batteries at 18ah each and i manged 127 km with average speed 27km/h and total bicycle weight 130 kilos (a lot of camping gear ). The average draw was 390watts and i did in a bit less than 4.5 hours. So with a extra 350 euros battery it will achive nearly 200km. i was testing if it will be viable to cycle from Greece to China and back. i believe that even i build a custom frame and make it a tricycle it will be able to cary the extra weight and a solar panel

[@antoniocruz8083]

I did the same experiment with only one battery connected to a trailer with 2X100W panels and I could go on indefinitely on a sunny day and going just below 20km/h.

[@Elated_Llama]

(E)Bikes are an amazing way to increase the catchment area of a train station Ideally, you can then further extend your range by being able to easily rent a bike at your destination station, to go the last few miles. The Netherlands does this extremely well, with most stations providing bike rentals, a hand full even have E-bike rentals.

[@LoneHowler]

Perhaps build a different trailer with a solid frame to attach a fixed panel to that can be adjusted for the best angle for the sun. And start out with two full one empty Intermodal transportation is great but not everywhere has access to intercity trains, like north America. This would be great for bikepacking to a remote location and you could camp at your destination and charge multiple batteries over several days

[@zonewolf]

I definitely appreciate the test as I’ve done the same with a kayak, 250w of solar power, and a trolling motor in my canal-saturated area, however, in terms biking. already an incredibly efficient human-powered system, you don’t need a motor, and I honestly can’t understand the e-bike craze when you can average well over 15mph/24kph just gently pedaling on a light single speed bike, as I do and have done (literally crossing the entire US)

[@Matahalii]

Some things could have been optimized as you know: 1. the route: paved roads or cycleways cost so much less energy, especially with a trailer. The horsepath on the canal is much more beautiful for sure but too narrow and uneaven for the trailer. 2. the trailer: single wheel versions have less friction alone because of less wheels, but in reality they are even more effective because they follow the bikes wheels and do not go through the flowerbeds too much and the whole ride would be smoother and more comfortable. 3. the human part of propulsion: train a little and you can minimize the electric assist, which if brought to almost zero, the endless travel is possible!

[@LightsOnMultiMediaMindArts]

There are ebike tourers who simply stop and recharge at parks, convenience stores and anywhere they can plug in while they eat and rest. Solar panels complicate the ride as you illustrate so well.

[@SSGrille]

Great experiment. I have always wanted to try that, now I know some thing to watch out for.

[@hellopsp180]

@12:00 cleaning your panels does NOT make it worse. Its because the panels had heated up during your test. Your panels output will decrease as it heats up

[@JMJM75257]

Id very much like to see a steel road/touring bike with something skinny and efficient like continental contact urban tyres with a low power mid drive kit like bafang 250w. Find a way to mount two 100w panels one on front one on rear rack and fit two batteries one on seat tube and one on down tube. I have a feeling if you tune the motor to have low current start and then turn motor down or up depending on terrain you can probably make it! its down to a battle of efficiencies!

[@AmaBossBeYourOwnBoss]

It can work ! Chek out Suntrip people on cargo bikes and bikes with trailers going on only solar power. Mostly minimum 400w pannel

[@joerivanlier1180]

Dust in the atmosphere, moisture, time of year (distance through atmosphere) all affect if the panel. You can check the expected irradiated power on the local weather website, your panel specs assumes 1kw/m3.

[@Ody-up6kg]

Awesome experiment and effort! Like so many things in life, theoretical and reality are two different things.

[@zechariahsmith1764]

I hope you do another experiment. I would recommend getting a different trailer. Perhaps a one wheel trailer that has the panel laying flat on the top.

[@mrkeopele]

there are more variables to your experiment, but, i found that flexible vibrating solar panels fracture connections between the inner cells. I found this out on an ELF e-Trike, most of them have solar panel failure and i saw broken foil strips in between each individual cells.

[@Spongesquid]

I've the feeling a reasonably fit pair of legs, a decent bike with a well maintained drivetrain and a couple of snickers bars is the most efficient way to go here.

[@clintwedel5704]

I have a tandem I converted to electric and a 170w solar panel, I might have to get a MPPT charge controller and put them together to see what I can do! Currently swapping out the BBS02 motor for a Tongsheng TSDZ2B (for the torque sensing PAS). Things for you to think about for next trial, tandem/longtail bike (instead of trailer), torque sensing PAS and a battery blender so you can charge the battery in use.

[@user-fy7ru4ii1i]

I bought a rear mount child bike seat, when by 1st child was born (took a couple years to grow into it). It was fun taking my 1st child out for bike rides. When baby #2 surprised us, I bought a front mount bike seat (now having a rear and front mount). It was fun taking them both for bike rides. When baby #3 surprised us, I sold the front mount (as the youngest one out grew it) and bought a bike trailer + kept the rear mount). So...I can take all 3 for a ride. 2 in the trailer and 1 in the rear mount. Now, I just gotta convince my wife to get her bike out of the shed.

[@thomashughes_teh]

If You want to take it in a trailer, put it in a bag, backpack, wrap sheet, etc. and tie it to the trailer. If e-bike battery design was standardized across models and manufacturers ( not currently even remotely a thing, but adapters could be ? maybe ?) battery swap stations on bike roads and in urban centers would work worldwide. Also, as car charging stations become more abundant e-bike chargers and e-bike fast chargers at such facilities might also find popularity.

[@chrismcgowan5180]

That was a low blow about Reading. I must restore the honour of my fabulous town (pretty much a city). Cage fight?

[@hughmanateecrisis]

In a lot of the shots, it looked like the edges of the panel were covered and/or there was a shadow over some of the cells, which would knock out that bank of cells. Probably reducing it to a 50w panel effectively.

[@fteoOpty64]

This is a scenic route. I wish to take one day. Good to have such experiments for fun and outdoors enjoyment.

[@stephenrichards3395]

In some countries they even have the mad idea of providing decent provision for bikes ON trains. I think distance is one thing, time is another. My plan for retirement is to cycle eurovelo routes with an ebike and trailer but with I won't be under time pressure so wont need to worry too much about charging as I go.

[@shpe11]

your panel is covered with that yellow tiny stuff(14:07) could drastically decrease output also be sure to use MPPT charger rather than PWM

[@SonnyDarvishzadeh]

I know your hypothesis was to make it fun and interesting, but here's my experience and perspective :) As an E-Gravel cyclist, I can see many improvements here. The choice of tires and their pressure, bike and trailer weight, motor efficiency, improved aerodynamics (frame design, rider position, clothing, aero bars, etc). Probably charge with larger panels when resting? it's more stable, cleaner and nothing's rattling when charging. I have two 250 Wh batteries and I can ride over 250km with them on mostly flat terrain. It would be a bonus to charge them with solar panels, but my body wouldn't accept more than 250 km in a single day. For climbs, each battery brings me up over 1000 meters, about 50-60km for a total system weight of 110kg. But back to your experiment, I never thought a 100 watt panel could ever deliver 100 watts to the battery in its most ideal scenario. Each of these components reduce a certain percentage: Solar panel (around 18-23%; ratings differ from factory to only 1 minute after each charge, they simply drop in % in real world), the converter module is usually around 85%, the battery charger (also similar to the MPPT module efficiency), and even the battery is never 100% in its optimal capacity, especially yours that are 2 years old. I would rather look for pit stops at cafes, restaurants and even free wall plugs in each city. Some even use car charge stations to charge their ebike. Since you have 2 batteries, carrying a spare charger (on a rear rack) to charge simultaneously would be a better choice than hauling a trailer (10-15 kg) and a solar panel (2-4kg).

[@TheKillerman3333]

i hypothosided this decades ago, and i finally see a youtube video of someone doing it!!

[@sietuuba]

If it's a semi-flexible solar module then their solar cells are in serious danger of developing faults by micro-fracturing, if the panels is ever actually bent much, or jostled repeatedly. Mechanical affixing requires considerable forethought and experience, which you have started to gain with this experiment! There's a wealth of information out there in the solar e-biking community on that aspect. The temperature coefficient of solar cells matters too of course, leading to less output at elevated temperatures, but losing half the nominal power output in pretty good insolation conditions like in your test afterwards leads me to believe that unseen physical damage is the culprit. It could be verified by backfeeding current into the solar module and imaging the panel for the resulting light (electroluminescence crack detection) to see the probable cracks it has developed, as well as cells that might be out of circuit due to other issues. There could be other electrical defects in play, which could for example drop half of the "strings" in a module out of circuit, though I suspect that particular model has only one string and some of the bypass diodes are simply bypassing some of the potentially broken cells in its single "string". Other than that, the issue could be in how the produced power is actually used electronically. It's a surprisingly non-trivial problem actually, fitting a e-bike battery's charging load to the production characteristics of a PV array in every possible operating condition that is, so more information on the characteristics of the electrical setup is needed for a fuller answer. It's quite a rabbit hole even for a trained EE, which I'm not, should you choose to jump into it!

[@vpnconsult]

Nice thought experiment 🙂

[@I_THE_ME]

I would have guessed that only half of the panel was working properly and the other half had broken during the trip.

[@SimonClark]

So I assumed this too and so tested this off camera - both sides are still generating!

[@NinjaWatermelon42]

Huh, I thought that was a slam dunk theory. How wired it's so low then

[@Beeeeeeeeeee]

@@SimonClark the tiny shadows from the wheel and yellow umbrella would have had an enormous effect on the power production. The cells are connected mostly in series, so if one solar cell goes down, the rest can't produce

[@ElectricityTaster]

​@@SimonClark Check the fine print. Maybe you bought a 100W solar panel but 50W are locked behind a subscription service.

[@frodothehobo9581]

Another thing overlooked is the increased friction of the trailer and the extra weight. Requiring you to keep the assistance higher (or sweat more).

[@dogzebra2708]

It would probably help if these machines were considerably lighter weight. If manual operation was as convenient as a manual powered bicycle, you could make up the lag in mileage. Giving you a chance to change two batteries, and cover some ground.

[@keriford54]

I've just been watching Jack Butler's long distance sun trip race with a solar powered e bike. I highly recommend watching it is on youtube. I still don't know how much difference there would be between non solar ordinary bike and solar e bike. However obvious things spring to mind, the solar bike has to be designed as a single unit, your set up has a ton of redundancy with the trailor set up and maybe even the two batteries. Pretty much all the bikes were recumbents to reduce wind resistance and the solar panels were mounted above the cyclist so there was a lot less dead weight and it sheltered the rider from the sun. His also had the hub motor on the front wheel and it had regenerative breaking. He did a lot of hill climbing so I think it probably made significant difference. As others have said, you definitely need to have a robust solar system that can take some shocks. Solar systems and batteries are both getting better so long distance solar bikes may be able to get more mainstream adoption over time, but we're not there yet.

[@adr2t]

In theory, you could try to get more area for a single panel by also constraining the amount of light the panels do get - mean less over all mass you would have to bulk around with. The other is to make a solar panel holder on the bike it self - so less wheels/fiction hits the road. Granted, the panel only get 50watts seems a bit of a problem too:) already cut in half.

[@gleamx1739]

i wonder how efficient that Bike and solarpanel would have to be to actualy sustain that distance. Could you make a followup video investigating why the solarpanel was so inefficient or what influence friction, heat, vibrations had and how those could be improved to make this come true.( i know that is more of an Engineering question sry ).

[@DavidCousins]

I notice you had a yellow object, maybe an umbrella laying lengthwise on the edge of your panels. That small overlap is death to your charging.