Solar panels for velomobile

[Kai]

I have a Quest velomobile that I have been renovating this winter. Yesterday I got an idea.
I sent e-mails to solar panel firms asking them to sponsor me with solarpanels installed on my velomobile. It was late in the evening but I quickly got positive few replies. I bet tomorrow I get more replies. In my opinion velomobiles symbolise same green values as solar panels. One firm was excited about my idea and promised to give me the panels I need! If many firms are interested, I can choose the best firm, get the best equipment, and I could even earn some money with advertising stickers on my velomobile. I want my own advertisement on my velo too, so my logo has to be biggest

But there will be many problems in this project.
-It is not easy to wrap a velomobile with solar panels? (although there might be flexibe panels made for boats) Too many panels and there won't be any space left for advertisements
-Solar panels probably will not produce enough watts to run electric assist full time ? (needs to be collected to a battery while parked)
-Charging LiFePO4 or Lipo is not easy because there are no chargers commercially available because it is a niche market for 48 volt batteries?

Let's imagine a long bike tour with velomobile, is it even possible to charge e-drive battery faster with solar than you need to use it? Would the added weight negate the benefits of solar panel's energy supply? For commuting solar panels might work. Drive 20 minutes with full power and let it solar charge for 8 hours at parking lot. Another option could be carrying additional solar panels inside velomobile while touring and when parked have them out unfolded collecting more energy (this option is tedious and in cities not a good idea. Panels cannot be left unattended)

Ofcourse I could have the panels more as a enviromental statement than real energy source and I could charge only driving lights, cell phone and perhaps a laptop. Or maybe I could get most lightweight motor and use only that much energy the panels can make in a day (use motor only for uphills). And I could have lightweight battery that has only enough capasity to match energy production. We have a 250W / 25km/h limit in my country so most of the time the motor would be turned off on flat lands since velomobiles are faster than 25km/h with human power. Should I forget solar panels for electric assist idea?

When negotiating with these firm about technology and prices, I don't want to be embarrased because of my lack of knowledge in this topic. Please advice me on this matter. Any opinions and advices are appreciated!

KAI

 

[Holocene]

Leave your solar panels at home tied to the grid. charge off the grid. Voila, your solar powered quest is finished.

 

[AussieJester]

Might want to look t this thread
http://www.endless-sphere.com/forums/viewtopic.php?f=6&t=46587
might give you an idea of the number of panels needed to be practical
on a e-bike.


best of luck

KiM

 

[dogman dan]

To charge a 48v 15 ah pack in one day, you'd need at least 150w of panel. Not impossible to carry on a velomobile, but you might need to have smaller size panels to tile the top of a more curved surface. Idealy, perhaps strips of panel 6" wide, then a polycarbonate shell over that for aero. But then you have half of them facing the sun,and half not.

To do it right, it would involve more than simply bolting a panel to the top of the velo ruining its aerodynamics. When considering carrying panels I keep coming back to the appeal of carrying them, and perhaps the battery too on a bob trailer. Seems to me you could make a bob trailer pretty aero with a good shell. Flat on top, again not ideal angle, but better than the far side of the aero shell. If the velo has a second battery, you could actually tilt the trailer at the sun to charge better when parked, while still able to ride some on a smaller battery in the velo.

For pure range extension, the same weight of the panels carried in the form of more batteries for the win.

But the concept of panel built into the vehicle is proven, in the form of the cochroach shaped solar 4 wheeled cars. So you could do similar things with a velo, stretching the top out flat and low as possible, and giving yourself a bare minumum of clearance to lean at the bottom edge. It just might work better based on a recumbent tadpole trike than with a two wheel that needs to lean. You'd also be stripping all the weight off the panels possible, tiling the skin with indivdual cells.

 

[John in CR]

Kai,

What's your timing on this? I'm starting to deal in exactly what you need, though with the PV modules I have you'd want to replace the shell of the Quest and make a new shell with the solar cells incorporated directly into the body of the vehicle. Maybe an initial test vehicle has the solar panels/modules mounted on the Quest body, but that can't be the long-term plan because other vehicles with the panels as part of the integral structure will be chosen instead. Those will soon exist.

Don't think "best" of anything, think "best value/performance" instead. The only thing hold EV's back is price, nothing more, nothing less, and there's definitely a market for a vehicle that harvests its own energy to run. The market for one that's $4k-6k is an order of magnitude larger than one that's $12k-16k or higher. The biggest problem with most startup EV companies isn't the product, it's the pricing that looks only for profits in the near term instead of viewing the near term as an investment in the long term.

What kind of performance and range do you want from the vehicle? How many watts of solar do you want to carry? What kind of per watt budget do you have?

 

[bowlofsalad]

I considered a very similar idea myself as yours not long ago. I concluded that it wasn't worth the weight and risk. I am sure you've seen solar cars, they are basically slightly larger bodied velomobiles with an electric motor. That is a pretty complicated setup. I thought that putting a 2' wide 4 to 8 foot long solar panel on a trailer on the back was an option. It would likely work, but I don't know if it's worth the hassle. It only works during the day, it would cost alot. It would be really cool and such. I did also consider carrying some solar panel as a sort of roof as well. Two 2 foot wide 2 to 4 foot long pieces would certainly be capable of carrying you a good distance. However, I am really concerned about the idea of heavy winds turning a solar panel into a sail. Could be seriously dangerous.

I'll just stick with the low density batteries we have now and hope for a rapid development in the lithium air area (BMW and toyota just teamed up). I don't know what the highest rate of charge is for an A123 pack, but I bet you could find an outlet and jack in when needed and forget about all the solar panelness, that is what I am considering in the worst case scenario, carry more capacity and charge up as fast as I can when I need to.

 

[dogman dan]

Thinking more about panels in a bob trailer, how about a curved clear aero shell top on it, allowing some tilting of the panels inside?

I keep liking the solar charging trailer idea because of it's ability to be both a portable charging station, or a stationary one as needed.

Likely to be a custom trailer, longer than normal, but low and narrow to stay clean in the draft. Not steel and heavy, but alloy or even carbon. Windsurf masts are cheap and available for a pair of carbon beams. Maybe even make the shell out of windsurf sail mylar material too?

The fact that you are starting with a velomobile makes this practical imo. I regularly scoff at folks who want to somehow bolt a big solar panel to a regular bike, ending up with aerodynamics similar to holding your coat open while riding.

 

[Kai]

I took my velomobile out from carage

Perhaps I got too exited about getting sponsors, but now my velo is finally rolling and firms can see it for real.
I start planning what motor to buy and how to install it to my velo. It has a jackshaft that could be easiest way to install a motor. Hub motors are out of question as all wheels are one side mounted.

KAI

 

[dodjob]

Like Kim mentioned it, look at the work of solarshift. This is IMHO the best way to understand where the "problem" lay. Is "Bicycle" is more a sailing vehicule BUT what he does with it is really a wonderfull adventure. You can follow him on facebook
You can completely forget the flexible panels which have a very very poor efficiency.
Also Solar panels are very sensible to their orientation toward the sun (see suntrackers for more effciency infos)
In real life, if ever mounted on a bike, you will only get a very bit percent of the anounced power. That's life :/
Finally, like it was said before, the ONLY viable solution is to mount your panel at home or pack them in a trailer and mount them somewhere, well oriented on a sunny day
Hope this helps!
Gruß,
H.