Not quite what I expected when I read the title.
Btw, the panel is 50W, and I assume the battery is stock, 672 Wh. That's 14+ hours of best-case sunlight to recharge fully. I wonder how practical is it.
Then you can bring your bike inside, in the shade, etc. — not having to always find sunlight to park in.
The only way bringing the solar panel with the bike makes sense is a multi-day ride. But as is being pointed out, you're going to be spending a lot more time sunbathing rather than biking under power.
The cost figures in this article about [rooftop,] wind do not take into account latest gen [Dyneema] ultralight rooftop solar:
"Rooftop wind energy innovation claims 50% more energy than solar at same cost" (2022) https://pv-magazine-usa.com/2022/10/14/rooftop-wind-energy-i...
> The scalable, “#motionless” #WindEnergy unit can produce 50% more energy than rooftop solar at the same cost, said the company.
> The technology leverages aerodynamics similar to #airfoils in a race car to capture and amplify each building’s airflow. The unit requires about 10% of the space required by solar panels and generates round-the-clock energy. Aeromine said unlike conventional wind turbines that are noisy, visually intrusive, and dangerous to migratory birds, the patented system is motionless and virtually silent.
> An #Aeromine system typically consists of 20 to 40 units installed on the edge of a building facing the predominant wind direction. The company said the unit can minimize energy storage capacity needed to meet a building’s energy needs, producing energy in all weather conditions. With a small footprint on the roof, the unit can be combined with rooftop solar, providing a new tool in the toolkit for decarbonization and energy independence.
"18 Times More Power: MIT Researchers Have Developed Ultrathin Lightweight Solar Cells" (2022) https://scitechdaily.com/18-times-more-power-mit-researchers... :
> When they tested the device, the MIT researchers found it could generate 730 watts of power per kilogram when freestanding and about 370 watts-per-kilogram if deployed on the high-strength Dyneema fabric, which is about 18 times more power-per-kilogram than conventional solar cells.
> “A typical rooftop solar installation in Massachusetts is about 8,000 watts. To generate that same amount of power, our fabric photovoltaics would only add about 20 kilograms (44 pounds) to the roof of a house,” he says.
> They also tested the durability of their devices and found that, even after rolling and unrolling a fabric solar panel more than 500 times, the cells still retained more than 90 percent of their initial power generation capabilities.
E.g. Hyperlite Mountain Gear sells Dyneema ultralight backpacking packs and coats. There are Dyneema Patch Kits that work for various types of gear.
Wise to look at Ultralight backpacking gear before buying regular camping gear. Solarcore Aerogel is warm and light and also in encased in PVA foam rubber which is like a new wet suit. https://twitter.com/westurner/status/1600820322567041024 Kayaking bags are waterproof, but are there yet Dyneema ones?
730-370 watts/kilogram is the number to beat (for DIY electric bicycle applications)
And rooftop wind is competitive (for charging offline batteries)
Presumably, bicycling is like ultralight hiking: wHr/kg is the or a limit https://en.wikipedia.org/wiki/Kilowatt-hour
A pedaling electric bicycler could tow a solar wagon, eh
I guess the sensible way would be just having bigger, fold down solar panel array and to deploy it where you stop.
Things may work out if you plan on having a stationary camp somewhere remote.
There are no easy answers.
If you leave the bike out in the sun all day, you can probably add 10-15 miles of range, which would be practical for some people (not everyone of course, but for many people, an e-bike wouldn't be practical even with infinite range).
But yeah 7-10mi realistically in most of the US or 5mi in the winter. That's not terrible, but it does require pretty perfect alignment and no shaddowing.
Also, the electronics are mounted out in the open and on top of a small bit of wood, that works well in the lab but if you're going to be biking and end up being rained on it may well cause issues, just using splash proof connectors isn't enough, you need to protect the electronics from the elements by eliminating direct contact with the elements. Much like in a car: all of the connectors under the hood are waterproof and they are under the hood, not out in the weather.
That said, it's a neat idea.
Source: I cushion my robots this way, haven't gotten to the ebike yet.
On the whole it isn't perfect but good enough for many years, I've run this setup for a year now and have once (at 5K km) inspected the wiring and the battery welds and everything seems to be holding up quite well. Things to be careful with: overpressuring the tires would reduce the amount of shock absorbing capacity quite a bit (and is definitely not recommended with tires this wide anyway), the rolling resistance of these is fairly high but that is just how they are designed. Then, obviously there is bumping in to things and falling at speed, which fortunately hasn't happened. But if it did I would immediately consider the battery pack a write-off in spite of being super well protected. I've done about 10K on it now and when it hits 20 I'll take the whole thing apart to see if there is any wear that is hidden from view. I'm mostly concerned with the battery welds and the wiring, those are the weak points, even with all of the wiring contained within the enclosure, routed carefully to never cross over any other wires and with the welds checked using a FLIR during a pretty rapid discharge (twice as fast as the motor could ever do).
The OP has mounted the charge controller and the motor controller to a piece of wood (which will flex a bit but not much) which in turn appears to be protected in only one axis (side-to-side) and is either free to move or rigid in the other two. The wiring runs 'cold' without any kind of extra protection through the wood that it is mounted on. The frame is unsprung as far as I can tell, which especially for the front is not a luxury on a bike this heavy, which makes bike+battery the unsprung weight (I think I see a saddle pin with a rubber mount so there is some flex there). That battery box may have some foam in it or some other suspension for the battery which is good.
As long as he's on good asphalt this setup will work, but as soon as you go on less perfect roads I think that it will give trouble over time. DIY stuff like this looks great on the day you build it if you don't build it for abuse, but exposed wiring is dangerous and vibration as well as the weather are going to be rough on this. I'm curious what it will look like a year from now if used intensively, and also how the wire runs are on the other side of that board.
End result, everything is perfectly potted except the topside of an aluminium heatsink.
So getting +50% charge in a day is not too bad.
In a pedelec after a certain point you and the battery are working together to maintain speed and it really doesn't take much battery. But there are so many variables that it's hard to talk about it meaningfully.
In their dreams maybe, that looks more like 40W sized poly panel, and it'll never get close to that unless they're driving it along the equator with active cooling on the other side.
Storing the bike outdoors continuously in the sun, wears on the condition considerably faster than indoors.
Having the solar panel attached makes for "all in one" articles, but seems rather limited on practicality for most people.
My personal preferred way to do this would be to have a stationary battery to charge up, and better solar panel positioning like you say, but that costs a bit more for that stationary battery. And if the only thing that battery/solar setup is used for is charging the bike, and you don't actually need more power then all that extra power is just gonna go to waste.
Still a fun project though, and not something I built to make a return on.
Modern fridges are often inverter drive, so should be easier to incorporate a DC power source. And they generally run all the time because they do variable-frequency drive.
Best part, it keeps working during power outages. Extra points for putting on a USB charging port (only works during the day, but still!).