Ok, so building a solar powered electric bike? Here's my story:
It all started when my wife and I moved back to Key West, Fl. once you leave you always want to come back!
Since our jobs are less than 1.5 miles from home (not to mention parking complicated at best.) it seemed appropriate to sell off our vehicle and use bikes. Of course living on this Island demands being different or unique and your vehicle should reflect that! To fulfill that demand I built a tadpole recumbent trike (2 wheels in front and one in the back, the comercial Greenspeed versions start around $1200) all out of old bikes and a chair from my hotels cafeteria. It worked great!
The downside sweating pedaling to work The Casa Marina Resort demands looking smart and smelling fresh!
Next step Currie electric drive motor 450 watts. Pull out the battery pack at night and charge it up!
1st evoloution!! After 6 months of riding the frame folded poor welding and bike tubes werent built for that.I blame the bike tubes but my welding is ugly at best.
2nd evoloution!! Weld up a 2x2 inch steel chassis, then weld a standard bike rear end, and add the 26 inch drive motor to the rear, with two new 20inch BMX wheels 14mm axles and Kevlar tires. Oh yea the extra weight had to change from the standard Currie battery pack 10 Ah and add 2 17 Ah batteries. I dare say this design could punch a hole in a car!
Renting apartments in Key West you have to move from time to time. Our new apartment is above a store front needless to say dropping an extension cord off the balcony wasn't an option.
3rd evoloution! Add solar panels? Why not! Two 15 watt sunforce panels!! It doesn't run the motor (YET!) but keeps the batteries up! 700+ miles and 7 months I haven't had to plug in to the grid yet!! Top speed of 16mph and range of 14.
Material and tools required:
2 matched bikes for parts or 2 Matched steering head tubes, one bike rear axle frame cut to the front of the pedal crank assembly, 1 spare pedal crank tube, sprocket, crank, and of course pedals.
1 2.5x2.5 tube of pipe the (main chassis)
1 2x2 tube of pipe pedal (crank boom assembly)
1 1.5x1.5 tube of pipe (cross bar)
Heavy duty BMX wheels. I have 2 20inch in the front and Currie 26 inch electric drive in the rear. There are plenty of designs on the net that are different, I encourage you to research and experiment.
Electric bike motor kit (Rear wheel)
Batteries to match the voltage(keep in mind more amp hours more weight)
Solar panels (The more power the better! Set to match the motor and controller voltage needless to say they must fit your design)
Charge regulator (Needs to match the voltage of the motor, battery system and solar panels)
Tie rod end and ball joints (Auto parts store or McMaster-Carr has a great website for all sorts of obscure parts like this.)
A comfy seat!
Welder (ARC, MIG, TIG personal preference)
Driil Press (highly suggested)
Hole saws for metal
electric meter for DC voltage.
Various hammers and tools of destruction (I especially prefer the BFH9000)
Many frosty beverages when you are drawing and planning this design!( Don't operate equipment while drinking!!)
Also keep small children away! There are many sharp and dangerous objects! (Not too mention all the cussing you may be doing while cutting welding and grinding, getting burnt etc.....)
Step 1: Building the Front End.
Building the head tubes(AKA steering tubes) are the most difficult. I used 2 old front forks from bikes cut the forks off and welded a mount for a 14 mm BMX axle.
They should have a negative 15 degree angle where the axle mounts when standing verticle.
These are where the front wheels attach and must be strong!!
After cutting the front forks off I pounded out a mounting bracket for the wheel and welded it in place.The box shape design keeps it at 15 degrees. Below is also a photo so you get a better view of the tie rod and steering setup.
Step 2: Steering Continued
Use a hole saw to drill a hole to match your steering tube you will want a nice tight fit for a neat weld joint. If you have the welding done to the head tubes on a straight tube, it should look like this. Next is the old notch and bend to hold the wheels at 90 degrees on the straightline.
Step 3: Cut the Steering Bar.
Yes notch out the cross bar to a 15 degree angle the wheels will now be 90 degree vertical. Weld the joints and your tie rod assembly Then bolt the tie rod into place. You will need to notch the main chassis tube so the steering head tube is in at an angle with the leading patch where the tire touches ground to the axle (On a 20" tire its 11 degrees). This begins the steering gear and tie rod as well as Akerman steering.
Ackerman steering helps keep the wheels from shimmieing (SP?) down the rode and keeps the wheels straight and true, it also prevents tire scrub because the wheels lean into the turn much like riding a 2 wheel bike.
When you get all your angles correct and crossbar square its time to start welding.
Step 4: Complete the Chassis
Weld the bike rear chassis into place (Make sure it is square to the main support!)
Weld your crossbar in place keeping in mind the 11 degree angle and ensure it is square to the main tube.
Add the front pedal boom and weld on the crank assembly make sure the crank assembly is a nice clean solid weld. (See picture #2)
Now would be a good time to prime and paint your ride. I haven't because I'm still experimenting.
After painting add your wheels motor batteries and brakes.
I can't stress this enough!! Get some good super heavy duty brakes!! Disc brakes if you can find them! With motor, batteries and steel frame this thing weighs in at about 90 pounds! Add a laptop, bag of tools, groceries, beer and 165 pound knuckle dragging maintenance engineer! You have a 275 pound harpoon travelling at 16mph! The ride is fantastic it's impact I dislike!
Step 5: Test Drive!!
This one I took while getting ready for Fantasy Fest a little Steampunk look.
And here is a ride down South Roosevelt.
Step 6: The Solar Jump!
OK enough fun test driving back to the shop!!
When we moved into out new apartment I had to plug in at the hotel I work at. This meant after alot of driving and touring on the weekends the batteries were quite drained and I resigned myself to pedalling. After a little bit of research I found the 45 watt solar panel set at Harbour Freight (another fun big boy toy store!) but I settled on the 60watt set I found on Amazon for $260 it is 4 15watt panels at 12 volts each.
But wait our Currie motor is 24 volts what do we do!!???
We hack Solar panel kit! (Keep in mind this may void your warranty!) Since I had 4 panels and couldn't figure out what to do with the other 2 (Seriously it would look like an airplane.) I hacked the frame to accomodate 2 panels rather than 4. (Keep in mind this frame is some sort of odd metric schedule 80 pipe standard pvc pipe wont fit it.) I bent a piece of 1/2 inch pipe from the crank tube to the front of the solar panel and another piece from the rear of the panel to were the old seat tube is.
Trim the terminal ends of the panels. take the positive end of panel #1 and the negative end of panel #2 and connect them.
grab that electric meter and test your voltage from the negative end of panel #1 and the positive of panel #2 you should have 26-28 volts in full sun.
Now you could connect the panels to directly to the batteries but I wouldn't recommend it.
Break out another $50 and find a 24 volt charge controller. HQRP sells a 20 amp 24 volt charge and motor regulator this prevents discharge of battery system from the solar panels at night, shuts off when fully charged, prevents overamping the motor controller and shuts down before draining the battery pack. Make sure your regulator at least prevents overcharge and discharge.
If all goes well you have you have a solar powered bike with a sunshade!
The future of this project can go anywhere!
Step 7: Future Plans
Improve the braking system!
Add fenders! (The rain and oil spinning off the front wheels is no so refreshing)
Dry cover for the throttle control and safety cut off!! (Driving in a downpour one evening the throttle had a short and wouldn't turn off.
Fiberglass rear panniers and mount solar cells to the panniers (More power!!)
Solar powered trailer with a rolling bar, cooler, blender and entertainment system.
Any other cool suggestions would be helpful!