Good idea or am I crazy? (Solar, trike, roadtrip)

[veloman]

Since I have this urge to travel, love biking, love electric powered bikes, love efficiency, care about the environment, and so on, I came up with this idea.

For some cross country road trip, strap one of these big solar panels either on top of a cargo trailer behind my bike, or get a trike recumbent and mount it above me to give me shade.

http://austin.craigslist.org/ele/1762883050.html

I would use my battery pack as a reserve for hills, and use a low powered efficient motor to assist my travels. In full sunlight, I'd get 150watts to the wheel. That'd be a nice boost at 15-20 mph speeds. When I stopped, my batteries would recharge.

Is such a system realistic?

 

[mdd0127]

Not really, at least not until panels are more energy dense. It would take more than 150 watts to carry the panel. Sorry.

 

[amberwolf]

And remember, that power output they usually rate them for is absolute max power you might get on a perfectly clear day at high noon on the equator.

Maybe it's not really *that* bad, but I wouldn't expect anything near that rating out of them constantly.

 

[swbluto]

It'd probably be more justifiable from an energy POV to plaster thin-film solar cells on a surface than to haul around heavy panels. But if you're "not doing much" to "traveling ratio" is greater, than the more justifiable solar power is since you could expect to charge your cells more often.

What I'd likely do, though, for long distance capability is haul around a propane generator. The fumes are far less carcinogenic and it doesn't stink as much as gasoline and they're purportedly quieter. I haven't found a cheap propane generator, however. I haven't found a light one, either, with a kW rating. They all seem to be 100 lbs. or greater. :|

Wait.. I'm searching again. it appears I can't find a propane generator under 2500 watts. Maybe that's what the weight problem was about.

 

[PedalingBiped]

Even if you can't get all your power from solar, you could still go.
bum power off of people you meet. Have a Great Adventure!!

This guy quit his job so he could walk from NY to OR. He's in Wisconsin now.

Here is the AP story
http://www.google.com/hostednews/ap/article/ALeqM5ixE0nrLPe6evuAxufPQuUio8ukHQD9FV3NE83

here is his website.
http://imjustwalkin.com/

Flickr
http://www.flickr.com/photos/imjustwalkin/

 

[bzhwindtalker]

I have a project similar in Europe with my custom built velomobile. But I will need ~2kwh of battery to make it happen I think.
Time to search for sponsors!

check this build also : http://www.triketrek11.com/
I exchanged some infos with Chase, It's cool to see that different people around the world come out with similar projects!

Adam

 

[dogman dan]

Of course you're crazy, but aren't we all here on ES? Carrying panels isn't a real good way to get the power, but carrying a small panel is a great way to get a tiny bit more range,(really tiny) while making a political statement. If nothing else, the panel could power other small conveniences like an ipod and cell phone.

Network up some folks with solar panels on the house for your charging needs along the way as much as possible. That way you can still have a green trip.

 

[yopappamon]

That's a very good price for the solar panel. 80 watts usually cost around $300 from what I've seen.

 

[veloman]

The panel weighs 36lbs. On a typical 6% grade at 12mph (fairly quick cycling speed), the additional weight will only cost another 60watts.

I would estimate that a 180w peak panel could give around 100watts on an average sunny day on a low shade route. Even if it can give 70watts, it still powers itself up most hills. Then on the flats, it would clearly assist me well.

But I would also have my battery pack so that my motor could put out 200-300watts on the hills.

The key would be to fine the best, lightest solar 'panel' or film. I barely know anything about solar stuff, just did some searching last night and saw that most are much more expensive than what I posted in that link.


Maybe there are solar film I could attach to a carbon fiber sheet, to mount above me?

I really liked the idea of providing myself shade. I hate baking in the sun, getting dark or having to slather on sunblock.

The ideas of finding places to recharge which have solar panels is a good idea too. At first, a few weeks ago I thought of how I could just do a full ebike trek across the country on my battery pack, Stopping every 20 miles to recharge and experience the places I go. My Bosch packs should have another 1000 cycles left on them (nearly new), and they wouldnt be too stressed with a low power motor. Maybe I'd need more battery for those far apart areas. Or I could just do a combo of cycling and ebiking to extend my range. I already am good enough shape to cycle across the country.

I'm currently building up an electric assisted road racing bike - a Cannondale caad3 road bike with aerobars, it's less than 20lbs, and my e-stuff will add another 20lbs. That's with a heavy 6lb scooter motor and 5 fatpacks.

 

[John in CR]

Veloman,

I'd suggest using raw solar cells, so you can incorporate them in a more aerodynamic structure than a flat panel. It would also save a lot of weight and money. Harold in CR and I split 1kw of cells for right at 50 cents per watt. I plan to build mine into curved lightweight panels to incorporate into my ebike construction. Obviously thin film cells would be better for this purpose, but I haven't been able to secure those cells in raw form.

I'd be very leery of the effects wind would have on the flat panel structure you propose. Before doing anything, test it with a piece of plywood.

Good luck with the idea though. On a sunny day 100 watts worth of solar panel could go a long way on our very lightweight EV's.

John

 

[veloman]

That sounds great John. Keep me updated on your project. I really need to learn more about connecting the whole system, and it's really just in the idea-stage right now.

Any suggestions for where to get raw cells for cheap like that?

Since my fatpacks are 36-40v, I'd like to make a solar array of 40 volts so I'd be able to charge them.


Any idea of how much power is lost during the conversion to chemical (battery) energy? Would it make sense to try to have a direct connection to my controller from the cells? I still would want to option to connect to the charger plug on my controller as well.

And yes, 100 watts is nothing to laugh when we're talking an assist or for recharging. When I ride my road racing bike, I average 160-230watts, and that get's me 16-21mph average speeds. With a lightweight system, 100 watts of power would be the difference between an 'all day - super easy ride forever pace" and a brisk, endurance pace that drains your legs after a few hours.

 

[Drunkskunk]

I like the Idea, but It can't be done on the cheap. a 180W-Max pannel is going to give you more like 90W reliably, and much less earlier and latter in the day. you would need alot more pannel than just the 1. And you're going to need much higher output pannels than what you can buy off the rack.
Solar racers, meant to ride as lightly and at efficancy levels most of us will never see, have a pannel with the footprint about the size of a large pickup truck. thats about what it takes to move a human in a fully enclosed, streamlined bike.

The voltage output from the pannels isn't stable, so you will need some kind of DC-DC converter to get the voltage into the bateries. otherwise, the voltage from the pannels may go low under load, or as a bird flys over, and you reverse current from them.

LiFePO4 Batteries recharge at 90% or so, with LiMn and LiCo recharging at 95%+. Nickle based batteries recharge in the 80% range, and lead acid batteries in the 50-60% range, roughly.

 

[dogman dan]

My my, crazier than we thought, wants to bike but doesn't want to get a tan. Of course, some folks do get burned really easy.

But some bikes, especially trikes do take to adding a roof ok, but in a head wind, it will slow you down by a lot more than 50 watts. Perhaps the most practical place to carry a panel would be on a trailer, with the trailer roof to hold the panels. Whatever you do, make it so you can tilt the panel towards the sun, at least while parked, if not while riding.

Where are you going to be riding? Here in the western US, 70 miles between plugs can be common.

 

[mdd0127]

I was also thinking not only of the weight, but rolling resistance, additional drag, etc., when I made my first post.

Putting a small panel or two on an e-bike to power accessories and give you a slow charge during periods the bike is sitting is a great idea. In fact, the first butchered paint rendering I ever did of an e-bike had spots for two small solar panels. I wanted to use some 4" triangular ones I had found. I don't remember how much they put out, but the idea was, whenever you're not riding, and the bike was in the sun, it would charge. For a long trip, you could ride at night and camp during the day while the bike charged back up.

Please don't laugh too much, but here's the pic. The black blob on the side is supposed to be a solar panel covering the electronics compartment. I know....

 

[John in CR]

It looks like it's worth every penny of your $5-7k pricetag. LOL

 

[mdd0127]

No, that's the one with $2,500 in parts that I gave up on and redesigned from scratch as soon as the project became a reality! I took about fifteen minutes and made that image with Microsoft Paint a looong time ago. That's what I was getting at in the other thread. Sure, you can throw an Agni on a cheap DS bike with a front freewheel, a little bit of lipo, and a controller, spend about $2,500 on parts and have an dual suspension e-bike but can anyone say scary? I just posted that to show the little solar panel idea. :wink:

 

[mdd0127]

It looks like it's worth every penny of your $5-7k pricetag. LOL

BTW, I never put a price tag on anything. I just said $1,500-$2,500 was way too cheap for something fun, reliable, and extremely tough.



Sorry, back to solar stuff.

 

[whiteblade]

I get raw solar panel's from ebay Which i am trying out. ( they are broken solar cells cut down to size )

http://cgi.ebay.com/25-3-x3-BROKEN-pv-SOLAR-CELLS-MAKING-SOLAR-PANELS-/140411776465?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item20b131add1

http://cgi.ebay.com/15-1-5-x3-NOT-BROKEN-SOLAR-CELLS-DIY-SOLAR-PANELS-/140412092781?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item20b136816d

Here's a his web site on how to make your own panels : http://sites.google.com/site/earthforsolar/home

You could put solar panel's on something like this :

 

[amberwolf]

Good thing I don't have any money to spend on those cells. I'd have another project for my copius spare time.

 

[rhitee05]

As John already mentioned, you'll get a 2-for-1 benefit if you make an aerodynamic shell and mount your cells on that. Fiberglass would be ideal if you have the skills.

You need a power tracker device to get usable power out of the cells. PV cells will have a particular voltage at which you can extract the maximum power from the cells, which changes depending on light conditions. A power tracker will find the optimum point and load the cells there, then you need to do a DC-DC conversion to give you a usable voltage. For efficiency, it would be best if you could do just a single DC-DC from the tracker directly to pack charging voltage, rather than one to say 12V and then use a standard 12V charger to your cells.

With an efficient setup, you could get a decent assist with 100-200W of solar power. Just keep in mind that you'll still need to plug your pack in to charge from the wall at the end of the day.

 

[SunCoaster]

Here's a link to my solar project from 20 years ago:

http://endless-sphere.com/forums/viewtopic.php?f=7&t=14388&p=214687&hilit=suncoaster#p214687

The SunCoaster has no pedals - built for a particular race class. The 4 panels typically give out 200 W in good sunshine; no solar trackers.

We kept the design minimal to keep the weight down and because of the low speed, no additional fairing was used, although at one time I wanted to get a luge suit for the driver... The shade and open air keeps the driver comfortable on a hot summer day.

At one race, we beat one of the $100,000 fully enclosed solar race vehicles when the driver got heatstroke.