440 Watt Regulated Pedal Power Bicyle Generator for iPod, Cell Phone, Portable TV or DVD player

This bike generator design is good for running low power devices such as:

- An iPOD through a 12V Car cigarette lighter adapter like this one.
- Cell phone chargers
- Portable DVD player

You can use off the shelf parts from local stores to make this 296 Watt pedal power bicycle generator or buy parts from Amazon.com

Through volunteer efforts, 24 of these pedal power bicycle generators were assembled and used for charging cell phones at a 3 day event with 60,000 people attending a day. More Info here.

Any one who can use a drill, socket wrench, hack saw, wire cutters, and crimpers can do this project.

Step 1: How It Works

I hacked together a quick LabVIEW program and some sensors to hook up to the bike generator so you can get an idea of how it works. The chart below shows actual data while it was hooked up in the living room to our Sony play station PS2. The game being played is Harry Potter and the Goblet of Fire.

This test data shows Volts, Watts, Amps, Rear tire RPMs, and Heart Rate. The time period was about 3 minutes.

Note that the green line is actual wattage from the bicycle generator. When you first spin up the bike to about 275 revolutions per minute, about 5 seconds goes by while the alternator is developing a magnetic field, then the internal 14.8 Volt DC regulator kicks in and charges a 2 Farad capacitor.

This is the reason for the big green spike right at the beginning of the chart. After 2 seconds the capacitor is charged, and about 10 Watts of power is being consumed by an AC inverter which converts the 14.8 Volts DC to 110 Volts AC (The same stuff that comes out of your wall socket in your home).

Also note the red line showing that the voltage is stable at 14.8 Volts DC because the built in regulator is doing its job.

Next you will see where we turn on the Sony Play Station and the green line jumps up to 30 Watts.

Step 2: 16 Bicycle generators on May 15th Ellen Degeneres TV Show

16 of these bicycle generators appeared along with Cameron Diaz on the May 15th Ellen Degeneres Green Show. I donated time and energy to make these bikes so the non profit group Global Inheritance could set them up on stage for the show.

8 Generators were setup on Ellen's stage, and 8 more were put into her over flow room next to the stage were they were hooked up to power two television monitors, some lights on stage, and charging 12V car batteries.

Step 3: Parts & Tools

To see pricing & order information click on the links below, or go 'here'
(1) Bike Trainer Stand
(2) Two 24 Inch pieces of Super-strut (Home Depot / Lowes)
(3) Lawnmower V-belt 5/8 " Wide 78" Long # B75
(4) Superstrut 90 Degree Angle Bracket (Home Depot / Lowes)
(5) 1 twelve inch piece of Super-strut
(6) 5PK 3/8" Cone Nut & a couple of 3/8 X 1.25 inch bolts
(7) 5PK 1/2" Spring Nut & a coule of 1/2 X 1.25 inch bolts
(8) 1/2" Threaded Rod with two nuts and slip washers (Home Depot / Lowes)

(9) 3/8" sholder bolt 3.5 inches Long or use threaded rod.
(10) 14.8 Volt DC Alternator 63 Amp Iternally Regulated at 14.8 Volt DC (Autozone P/N DL7140M)
(11) Open House H218A 18" Custom Installation Enclosure
(12) 2.0 Farad Digital Power Capacitor
(13) TERMINAL STRIP 8 CIRCUIT (Center spacing of 0.562 inch, Accepts up to #10 AWG, 30 Amps per terminal)
(14) Meter that shows volts, Amps, and Watts
(15) DC to Dual-Outlet AC Power Inverter
(16) Cigarette lighter receptacle Splitter so you can plug in a cell phone charger or game adapter for portable video games.
(17) Fully Insulated Male and Female Crimp Connector rated for 10-12 Gauge wire
(18) 6 of the yellow 3/8 inch crimp ring terminals And 10 of the regular size yellow 10-12 Gauge Vinyl Ring Connectors
(19) Jasco #52194 4W White Night Light
(20) Size 12 Stranded wire 10 Feet (Home Depot / Lowes)
(21) 30 Amp Fuse and 15 Amp Fuse (Auto Store)
(22) In-Line Fuse Holder (BP/HHM) 5 each
(23) Crimpers used for Crimp on connectors
(24) Wire cutter and stripper
(25) Drill and 5/16", 1/2", and 3/8" drill bits

OTHER ITEMS NEEDED:
Bastard file to remove burrs
1/2" Deep Socket

Step 4: Un-box The Ascent Bike Trainer Stand

The Ascent Bicycle Trainer Stand comes packaged in a plastic bag with an upper and lower Styrofoam block. Keep the box because you can use it to ship the pedal power generator later after you are done.

Road bike or Mountain bike with "Quick Release" axle

The Ascent bike stand is supposed to work with a road bike or mountain bike that has the quick release lever. You know the kind that doesn't require you to use a wrench to remove your bike tires. You can get it to work with a regular bike axle that has nuts on each end, but the risk is that the stand may release the bike when you are riding it and cause personal injury.

NOTE!! It is not designed to work with a beach cruiser type bike which is a bike with a single rear gear. This is because the axle is too short on a one gear bike. The photo of the axle shows you what kind of bike axle the bike trainer is designed to connect to.

Step 5: Remove Screws From Ascent Magnetic 3 Level Trainer Friction Roller

The Ascent Bike Trainer Stand comes with a friction roller that just wastes all of the useful energy you put out. Let's toss it in the scrap metal recycle bin.

At this point you will need to use the 5/32 Allen wrench shown below to remove the two screws shown at detail 1 and 2 in the picture. After you have removed the screws put them back in the silver barrel threaded barrel they came out of so you will not loose them.

Step 6: Step 4 - Remove Rubber Retaining Ring

Use some needle nose pliers or some one who has really long & strong finger nails to remove the rubber retaining ring of the end of the metal support shaft.

Once this is off, gently shake the friction roller around and push on the end of the support shaft with your finger.

It will then slide out.

Step 7: Find The Strut

Make your way through the tumult to the electrical area and find the spot shown in this picture "HERE" . That is the Superstrut rack section.

Pick yourself out a fine straight piece of Superstrut and try to make it out the store without mishap because it's really long and awkward to carry around the store, and if it happens to drop on the floor on accident like it did with me, it's so loud that people will hear it from one end of the store to the other.

Step 8: Transport Strut To Parking Lot

Pay for the Super-strut and get it out to the parking lot.

Since you are working to achieve a small energy foot print and trying to conserve, you probably drive a fuel efficient car like a 1990 Honda Civic. This can present a challenge when you try to go to Home Depot to get your piece of Super Strut. Namely because it only comes in 10 foot lengths. You can see the piece below balanced on the shopping cart with the Honda Civic in the background.

Step 9: Locate Saw

At this point you reach into your front seat of your ride and grab your trusty hack saw.

Step 10: Hack The Strut

After about 100 strokes of your mighty blade, the Super-Strut yields.

NOTE: the piece you cut has sharp edges that can cut your hands. Handle with care. Bring a file with you to file off any sharp burrs that are there. Now you can easily load the Superstrut into your car and head home.

Step 11: Cut 24" Pieces of Super Strut

Now cut two 24" long pieces of Superstrut as shown in the photo.



NOTE: the piece you cut has sharp edges that can cut your hands. Handle with care. Bring a file with you to file off any sharp burrs that are there.

Step 12: Cut a 9" piece of super strut

Cut a 9" piece of strut as shown.

NOTE: the piece you cut has sharp edges that can cut your hands. Handle with care. Bring a file with you to file off any sharp burrs that are there.

Step 13: Mark Your Strut for 1/2 Hole Location

Mark Your Strut as shown in the picture.

Step 14: Drill your 1/2" Holes

You have three options for this step. (1) Use a small drill press to make your 1/2" hole (2) Use a hand drill to make your 1/2" holes (3) Get some one else or machine shop to drill your 1/2" holes.

If you use option (1) or (2) read the safety instructions in the manual that came with your tools. You are liable for injury or damage caused by your failure to comply with safety and operating guidelines of your tool.

Option(1) is the best in my opinion. For those of you whose modus operandi is to constantly try to justify buying more tools for your garage (like me) now is the opportunity to get a small drill press for $85 at your local hardware store. A drill press is nice because it drills straight through the Superstrut. With a hand drill this is a little harder. Note that the holes need to be straight through the Superstrut or your pieces will look crooked when they are mounted to the stand.



For this step you have to drill completely through both sides of the Superstrut. If you choose your drill press, set it to low speed. Don't press too hard. It should take about 1 minute per hole. NOTE: The tills (shavings from the hole) are HOT! You must wear safety glasses when doing this. You could get small piece of metal in your eye like I did on another project. It caused a rust ring in my eye and I had to do to the eye doctor to get it out.

Step 15: Remove Burrs From 1/2" Holes

Use a larger bit to scrape the sharp edges from the hole. If you don't have a larger bit, then use a round rod hand file.

Step 16: Assemble the Superstrut frame

Put the strut pieces on the 1/2 Threaded Rod and slide them into the bike trainer stand bracket as shown in the photo.

Step 17: Attatch Alternator Cross Mount

This is the Alternator mounting cross piece. You will use the cone nuts and some short 3/8" X 1" bolts.

TOOL: Socket wrench with 4 Inch Extension.

Assemble as shown.

Step 18: Drill mounting holes in L-Brackets for 68 AMP Car Alternator

The hole in the L-bracket does not work for mounting the bike generator. You will have to make a small hole as shown in these 3 pictures.

Step 19: Put the L Brackets on the Alternator

Mount the L-bracket loosely to the alternator as shown. Loosely attach the spring nuts as shown.

Step 20: Slide Alternator On To Support Strut

Remove the springs from the nuts because they get in the way. Snip them off with a pair of wire cutters.

Slide the alternator on to the support cross piece as shown. Snug the bots up hand tight with enough play to allow you to make some adjustments.

Step 21: Remove Rear Bike Wheel and Tire

Turn your bike upside down and remove the rear tire. The ascent bike stand comes with a spare quick release axle. It has hardened ends in the optimal shape to fit with the Ascent Bike stand. If you quick release axle has plastic ends, don't us it! Use the axle that comes with the bike stand.

Remove the tube and tire from your rear wheel so it looks like this. You can leave the rubber liner thing on if you want. It doesn't seem to make a difference.

NOTE: Make sure that your quick release handle is on the opposite side of your wheel that your gears are on. It must be that way to work in the Ascent Bike Stand!

Step 22: Put The Belt On

Put the belt on as shown.

Step 23: Put the wheel back on the bike frame.

Put the wheel back on the bike frame as shown in the picture.

Make sure the wheel is equi-distant from the frame. This is a very common mistake. Notice in the picture below how the gaps between each side of the wheel and frame are the same size. you need to do the same comparison check.

Step 24: Mounting Your Bike To the Ascent Magnetic 3 Level Trainer

Follow the instructions that came with the Ascent Trainer to mount your bike.

Some of my tips are:
Unscrew the tension knob out all the way as shown in the first picture.

Insert the axle end first that does not have the handle on it as shown in second picture.

Adjust your quick release handle so that it is on the top of the axle. Next adjust the landing cup of the bike trainer so it's wide opening is also facing upward. This will allow you set the axle end right into the cup as you tighten the tension knob. (refer to 3rd picture)

Step 25: Aligning the belt to the wheel

WARNING: DO NOT TEST OUT YOUR BIKE PEDAL POWER GENERATOR WITHOUT AN ELECTRICAL LOAD HOOKED UP TO THE ALTERNATOR - IT WILL KILL THE ALTERNATOR. IT HAS TO HAVE AT LEAST a 150 OHM Resistor across it or a small 2 Watts Light Bulb. That way the regulator won't go to high voltage output , and burn out.

Since you only hand tightened the bolts, you can know adjust the car Alternator as shown below. By doing a proper alignment, you have a more efficient bike generator because there will be less friction. And it will keep the belt from jumping off when you are pedaling.

When alighned, the belt should look like the picture. Also make sure the alternator is square wit the rim. Adjust the angle of the the alternator so its pully is perfectly aligned with rear wheel.

Step 26: Cut Alternator Hook Up Wire

Prepare the In-Line Fuse Holder wire by crimping on a 1/4" inner diameter ring terminal on one end and a female spade connector on the other.

Next prepare a 9 inch black wire with a large 3/8" inner diameter crimp terminal ring on one end and a crimp on male spade connector on the other. These need to be YELLOW which means these connectors are rated for high current up to 20 Amps.

Step 27: Attach Hookup Wire to Alternator

Use lock washers when you put these on to help make sure they don't get loose.

Make sure you have a 20 Amp Fuse in the fuse holder. This 12 AWG wire is only rated for 20 Amps. So do the right thing and play it safe. Even though the fuse holder comes with a 30 Amp fuse it's not ok to use it.

Step 28: Lay Out Your Low Voltage Electrical Box

(1) First lay out your electrical box the way you want it.

(2) Next Mark your holes with a sharpie

Step 29: Drill & Clean Holes

(1) Get a scrap piece of wood to put under the electrical box so you don't drill a hole into the nice table below like I did.

(2) Drill your holes in your box. Use a 1/4" bit.

(3)De Burr your holes for safety reasons - to avoid cuts

(4) Use a vacuum to clean up the shavigs - they are sharp!

Step 30: Mount Box ELectrical Components

Use some 8-32 machine screws that are 3/8" long. Also you need some lock washers.

You need two people to make this go quickly without dropping parts. Tile the electrical box up on end. Have one person hold the DC-to-AC Power Inverter part being mounted while you stand at the rear of the box and put the lock washer and the nut on.

Mount capacitor, terminal strip as shown in photos.

Step 31: Cut the ends off of the Watt Meter

Now cut the ends off of your Astro Flight DIGITAL WATTS/VOLT METER
as shown.

Step 32: Strip And Crimp Watt Meter Wires

Now strip the ends of the wires so you can crimp some connector terminals onto them.

It should like the picture below when you are done.

Step 33: Install Watt Meter

Now connect the right side (Also known as the supply side) of the Astro Flight DIGITAL WATTS/VOLT METER to the terminal strip. Tighten the screws firmly to get a good solid electrical connection that will handle 20 Amps. Don't over tighten! It may strip the threads of the screw.

Step 34: Modify Cigarette Lighter Plug Splitter

Next take off the male connector of the cigarette lighter plugs. These are used for low current charging of cell phones or game poys, or portable play stations or I pod devices. Strip the ends of the wires so you can put crimp on ring terminals onto them.

Step 35: Verify & Label Wire Ends of Splitter

Thes plugs are what you can use to charge cell phones with. They are optional.

Use an ohm meter to make sure you know which wire is positive and which is negative. If you don't do this right, you could end up blowing fuses or damaging your bike generator. Set you $10.00 volt meter from radio shack to a resistance measurement.

Next put one hand probe on the end of one wire and the other Ohm meter hand probe on center contact post of the cigarette lighter plug. You will see it when you look down into the barrel of the cigarette lighter plug. If the ohm meter shows 0.2 to 1 ohms then you know the wire you are holding is connected to the positive terminal.

GET a piece of tape and mark that wire so you make no mistake when putting it together. If the ohm meter doesn't show any measurement change when you touch the two ponts, then switch your hand probe to the other wire end to confirm that it is the positive voltage wire.

(2)Do the polarity check described above on both pairs of the ligarette lighter sockets. Now twist their wire ends together. Make sure the positives are twisted together.

(3)Now crimp on the ring terminals to the ends of these wires.

(4) Now to make extra sure you don't get mixed up, mark the conectors positive and negative with a permanent marker as shown below.

Step 36: Make 10 Inch Jumpers With In Line Fuse Holder

This step is to enable power to the cigarette lighter plugs. If you don't plan on using the cigarette lighter receptacles for charging cell phones then you can skip this step.

The wire needs to be size 12 AwG, black and red is preferable.

Prep an In-Line Fuse Holder with two crimp on ring termals as shown below. This will hold a 10 Amp fuse for whatever you plan on providing power to. The reason why it has to be 10 Amps is because the wiring fo the cigarette lighter plugs can only handle a max current of 5 Amps each. So 5 + 5 = 10 Amps.

After you prepare the In-Line Fuse Holder cut a black wire of the same length and put crimp on ring terminals on both ends of it.

If you want to charge 10 cell phones at once, you can buy a splitter to plug into the these receptacles. This will give you more placed to plug the cell phone chargers into.

Step 37: Attach Jumper Wires To AC Inverter & Terminal Block

Connect one end of the black wire to the negative (Black) terminal of the 450 Watt DC-to-AC Power Inverter terminal along with the negative (black) wire from the Astro Flight DIGITAL WATTS/VOLT METER as shown on the picture on the right.

Then connect the other ends of the two wires as shown on the left.

Now connect the cigarette lighter receptacles as shown in the picture.

Note:
This step is optional. It is only necessary if you plan on using the cigarette lighter receptacles for charging cell phones or other 12V type of electronics.

Step 38: Hookup Negative Side of Capacitor to Terminal Strip

Now you are ready to hook up your 2 Farad Digital Capacitor.

This is a really cool cap because it has a slick bult in blue LED voltage meter so you can always know what exactly your generator is running at.

You have to look very carefully at the markings in the plastic housing. Make sure you see which one has the plus sign and which one has the negative sign before moving forward.

REMEMBER: if you want to power up a TV set, having short thick wiring to the DC-to-AC Power Inverter is the key. This is because a TV set has a very large current spike when it turns on. So make the wiring short, and the crimps of a good quality.

(1) Remove nuts at end of terminal shafts
(2) Crimp a 3/8" ID (inner diameter) connector onto the end of a black 12AWG Wire as shown in the picture. Attach this end onto the NEGATIVE terminal of the 2 Farad Capacitor- it is VERY IMPORTANT THAT YOU GET THIS RIGHT!!
(3) Route your black wire over to the terminal strip and cut the wire to a length that will reach the terminal screw as shown in the next photo.
(4) Strip and crimp on a nother connector - the smaller ID size to connect to the terminal block. Do a tug test on the connector and wire to make sure it is secure.
(5) Use a phillips head screw driver to tighten

Step 39: Connect Positive Side of Capacitor to Terminal Switch

(1) Cut a length of size 12 AWG red wire so that it will reach from the Positive side of the capacitor to the terminal strip.

(2) Strip each end so that 3/8" bare copper is showing.

(3) Use wire crimpers to crimp on connectors as shown in the photo. One end has the larger 3/8" inner diameter terminal. That end will be connected to the positive side of the cap.

(4) Install the red wire as shown in the photo. Do not tightend to the capacitor side yet. Just the terminal strip side.

Step 40: Connect 10 Feet of Wire to Capacitor

Now it's time to make a wire connection from the power box to your bicycle generator.

(1) Buy about 10 Feet of size 12 AWG Stranded black and red wire.

(2) Strip the insulation of each end so about 3/8" of bare copper is showing.

(3) Use crimpers to crmp on large yellow erminal connectors that will go onto 2 Farad capacitor

(4) Slip the ends through the box as shown.

(5)Tie a not in the wire as shown in the photo. This will act as a strain relief in case some one trips on the wire some day.

(6) Connect the yellow terminals to the capacitor termianls. MAKE SURE YOU PUT THE RED wire on the positive terminal. You must get this right or very bad things could happen.

(7) Use a 1/2 Inch deep socket as shown to tighten down the terminals. DO NOT OVER TIGHTEN. The nuts should be just tight enough so that the ring terminals can't slide back and forth around the shaft when you push on them with your finger.

Step 41: Twist the Wires

The ten foot red and black wires are very easy to get tangled in so you need to twis them together using a drill as shown.

(1) Cut your wires to ten feet. If you want to cut them shorter you can do that.

(2) Tighten the chuck on the drill so the wires are securely held

(3) SLOWLY Rotate drill as shown in video. YOu need to have another person hold onto your box so you won't pull it off the table.

Insert ends of wire into drill.

Step 42: Add crimp on connectors to end of 10 Foot Wires

Now you will crimp on some connectors to the 10 Foot pieces of wirs as shown in the picture.

You will need to strip and prepare the ends of the red and black wires as shown below. The red wire needs to have a male yellow crimp on spade connector. And the black wire needs to have the opposite- a female yellow spade crimp on connector. This will help to ensure you hook up to the bike generator with the right polarity.

Step 43: Install Night Light

The GM one wire alternator only regulates to 14.8 Volts if it is hooked up to something. So you need to install a small 4 Watt night light so that the voltage does not creep up over 15 volts. Going over 15 Volts is bad because if it does this, the AC inverter shuts down by going into over voltage protection mode.

Install a 4 Watt night light into the Cobra Power Inverter

This will make sure that the inverter has some kind of load on it so that bike generator won't over shoot the inverter's operating range of 15 volts.

Note that many night lights are automatic and only turn on at night. So if you have one of these automatic lights, put a piece of dark tape over the light sensor on it to block out the light.

Step 44: Final Hookup

Now connect your 10 foot wires to the connectors on the car alternator. YOU ARE READY TO RIDE!!

If you are just charging cell phones or a car battery, then turn off the AC inverter.

If you are providing power to the television, playstation, or something else, then make sure the AC inveter button is in the "ON" position.

Step 45: How It Looks Hooked Up To A Playstation PS2 Video Game

Now you're ready to be a green lean power machine!

The photo shows how it looks when you hook up your bike generator to your playstation video game. If you want more information go to pedalpowergenerator.com.

Comments

[dieselsporter]

I would recommend a five amp fuse. Your calculations for 10 amps are correct, but the lowest rated part of that circuit is five amps. The fuse should protect the lowest rated part of the circuit. As an alternative, use two five amp fuses. Put one in line with each individual power port.

[Milke1991]

Does this bicycle could generate enough power for my pc? I'm trying to do this for a science fair.

[ssleeper]

I must be missing something. What is the purpose of not having a battery? Aren't you just using a bike to spin the alternator instead of a Windmill?
Is the object to have a simple system to charge things and get some exercise.
I apologize but I am just starting to learn about alternative energy (I have alot of fabrication expierence) and am trying to learn how to design these things. I would like to be able to incorporate this idea into building a small windmill.
I like the idea of adding a flywheel or even using two recumbants for pedaling comfortably while watching TV.

[ljfresh]

Does it matter what type of alternator to use? I can find 12 volt but the amps are different then 32.

[Noblenutria]

Isn't it better to use a generator with permanent magnets?

[bariwonderful]

Used this as a guide for my own bike generator. We are using it at SDSU as an outreach tool for sustainability and energy efficiency programs. Students love it powering the music at our farmers market and it was a big hit at our national conference.

Many thanks,
The SDSU Green Campus interns

[jj.inc]

small electronics, damn this could power my computer, excluding screens, and speakers.

[nav_lexy]

What if you just plugged the generator up to a 12v 7ah battery. At 296 watts how long would it take to charge a battery?
Great idea...

[vemsom]

1 W = 1 V * 1 A

A 12 Volt 7 Ah battery can store or deliver 7 amps at 12 volt for one hour. Or 12 volts at one amp (12 Watts) for 7 hours.

12 V * 7 A = 84 W

(84 / 296) * 60 minutes = 17

So. 17 minutes. :)

[manuka]

I'm a great bike fan & applaud their whole earth engineering applications when normal electrical supplies are not available- lathes,grinders & sewing machines etc spring to mind. However I beg to differ about that quoted "100s of Watts" sustained power output. We humans are usually only good for ~50 Watts output over any length of time, & even this can become a pedaling chore. Prime condition athletes & Tour De France bikers can certainly pump iron, but "100s of Watts" can only be delivered for ~30 seconds by most people. You just need to conduct an energy physics "running up the stairs" experiment to establish this! Rather than pedaling to just charge batteries simply use a solar panel - PV prices have fallen to under US$5 a Watt. A typical 4 hour solar resource onto a 10 W panel will deliver 10 x 3600 x4 = 144 kJ with no effort at all ! That sort of energy could be used to later run a 100 Watt electrical appliance for 144,000/100 = 1440 seconds or ~20 minutes. Our feeble human energy levels are IMHO better used for more precise application & exercising - firewood chopping, gardening, lawn mowing, building a playhouse or home extension, playing ball games with your kids, rustling up a meal from scratch etc.

[Opus the Poet]

I ride a bike daily and have been tested for my poser output at the 8 hour, one hour and one minute levels. I'm not a racer just a very fit individual (I'm normally lanterne rouge in my local bike club's races) and I can do 150 watts for 8 hours, 220W for an hour, and 800 Watts for 1 minute. That one minute output requires several hours of recovery time before I can put out more than 75 W.

[dhellew2]

A couple of suggestions to the project. While true that this isn't the best use of 'man'-power it is fun to try things anyway. The bike needs a flywheel. This gives the opportunity for intermittent rest periods so one can pedal longer.

Another possibility since this is for fun and exercise and not about the money why not add the solar panel too. Then perhaps us puny humans could go a few more miles. :-)

For a real challenge, put a car headlight on the bike and see how bright and how long you can keep going.... not long I assure you. Amazing how hard your car engine works for the small amount of fuel it consumes.

[manuka]

I'm sure I've mentioned this before, but repeat that the average human is hard pushed to churn out even 50 Watts for any length of time. We're puny creatures after all -even using our "powerful" legs.  Although initially "fun" & perhaps sociable to group pedal away like this, it's however a waste of our potential!

There's almost always better things to do than static pedalling, especially intricate productive work with crafts, gardening, cooking, child minding or reading etc. Even go for a walk or bike ride!

Given the abundance now of solar PVs it's far "greener" to use (say) a ~5-10 Watt panel (costing  ~US$30-50 ) over a few hours to do the charging instead.

[SpikeFiend]

Photovoltaics are hardly green. That 5-10W panel will likely never repay the amount of energy that went into making it.

The bike would allow you to get some excercise while, say, watching some TV...which is more productive than just watching TV.

It also works at night, indoors, and on cloudy days.

[lalalaux]

Waste of our potential? I think you're missing the point, and potential in this project.

Granted I wouldn't want to use one of these as my only source of power, that doesn't make it a useless idea. For instance, I can see one of these being great set in front of a tv, turning a mind numbing and unhealthy activity into something a little more "productive" while getting a bit of exercise.

Or you want to do something physical and the weather is nasty (because it's not always sunny). Or your rent and electric bill are both do and you only have the money for the former. Or.. I can think of tons of stuff you can do simultaneously while "static pedaling" (reading, singing or listening to music, having a conversation, etc). Maybe though, once in a while, it's nice to do something sort of meditative and not intensely mental.

Truthfully though, I'm so tired of this idea that people always need to be doing something "productive"! What is productive anyway? What if what I want to read instead of "static pedaling" is a gossip rag? What if I hate kids? Then it's not very productive or positive for me to be minding them, I would think.

I could go on and on and on, but I won't. And I don't mean to be offensive in any way, so please don't take it that way. I just strongly (I won't even go into the "puny" comment...) disagree with you .

[dreadengineer]

I think Manuka's point is just that you aren't going to have any impact on your electric bill or total energy usage. 100 watts for 1 hour costs about 1 cent. Certainly it doesn't hurt anything if you were going to exercise anyway, you just shouldn't have the impression that you're going to save resources, etc. with a bicycle generator.

[TheWelfareWarrior]

I didn't read all of the comments... But a 1 wire GM alternator is a pretty common find at a junkyard. Why buy new if there's a used one that's clean and decent?

[Tim Temple]

This is good and close to what I came up with.

But how about the other end of the circuit? Think 12 volt circuits. We need LED lights and even strings of LED lights. Heavy extension cords will conduct 12 volt electricity to neighbors so they can have lights at night, too. They can help charge the battery for the day. They become vested in common security as well.

When things go bad, this is useless for anyone living in a megapolis. The government will relocate the survivors.

[DIY Dave]

So you don't need a charge controller to keep the alternator from overcharging the battery?

[Prometheus]

Any alternator with an internal regulator should already have that implemented, and even replacement external regulators also have the same protection. You should no more worry about overcharging the battery here as you should about overcharging the battery in your car.

Besides, it's more likely that you will tire long before this could be an issue, and car batteries are remarkeably-durable anyway, especially if you consider the harsh conditions they normally operate in.

[ac-dc]

Car batteries aren't all that durable at all. If by harsh you mean temperature extremes, they are only extreme to humans, not to a liquid (so long as it doesn't get below it's own freezing point), plastic, or metal.

Car batteries will be badly damaged if drained fully a few few times, will boil off liquid if overcharged. They are not very durable at all if not implemented properly, and don't even last very long at all if you consider the typical car battery might be drained only 5% of it's capacity about 5000 times before it fails in real world "harsh condition" use - this is far below full cycle capacity of a NiCd battery for example.

[DIY Dave]

cool thanks

[dermord]

so you have to ride to play?

[Dr.Bill]

I don't see a battery to energies the field coil. How do you do it?

[bdwhaley]

You don't need a battery because there is enough of a residual magnetic field within the alternator to allow it to start generating 14.8 volts after 3 seconds of fast pedaling. Watch it done on this video:

http://www.youtube.com/watch?v=bJFGEQRWxz8

[Prometheus]

Actually it's not residual magnetic field left (you may be thinking of older automotive generators), but because the alternator automatically uses some battery power to get one started, and with the mechanical power keeping things moving, it snowballs until it can sustain it's own field. Fortunately, it can start this reaction with as little as 1 volt.

I'm glad to see more people getting on board with this idea, because countless trillions of watts are lost to heat on exercise-bikes worldwide every day. By actually harnessing this power, it decreases the carbon-footprint of a person/household by a great deal.

Kudos to you for posting this project, because exercise bikes are stupid when they aren't actually salvaging that lost power. 100 Captain-Planet points to you, and a bonus 5 internets for intelligent design in the project.

As a suggestion, you could try weighting the wheel (making sure it's centrifugally-balanced, of course), because while it may take a little more energy to get it up to speed, it would actually reduce fatigue dramatically, having only to maintain the momentum. As a well-seasoned ex-cyclist, I can assure you that you will feel the difference while you are on it. It's much easier to maintain momentum than to sustain it without mass. That's part of why engines have flywheels.

Awesome project, I love it.

[lil_agelu4life]

Can me and my physics group use this as our science fair project? (thats if we can get it 2work lol) It is sooooo kewl!!!

[bdwhaley]

Sure, But I would recommend using the permanent magnet DC motor as a generator and make a floating ball go up and down using an AC Yard blower. People really enjoy that. The plans for doing the Permanent magnet DC Motor / generator are here:
http://www.scienceshareware.com/build-your-own-generator-bike-trainer-stand.htm

[ctonks]

 Hey Brad,

can you tell how you hook up the AC yeard blow to the DC generator.. I can see some many applications for this. Thanks Colin (electricpedals,com)

[Prometheus]

Actually most electric leaf-blowers will run on DC just as they are, since an ac induction motor cannot generate the speed needed. They usually use permanent-magnet or series-wound (universal) motors, so as long as there is no speed-control (just on/off), you can just plug it in as it is. If there IS a speed-control, you will have to bypass it because DC will instantly destroy it and possibly cause a short/fire.

[sirant]

Great project! I remember 25 years ago a similar thing at a kids science camp that should have been implemented into common practice. They had a bicycle powering a television.... Imagine if all televisions in north america were bicycle powered.... There would certainly be a far smaller weight propblem per capita!
But your idea is awesome too. I'd love to have a cike to commute on that charged my electronics as I went...

[ja.dzado]

 Now imagine that everyone followed the wasteful instructions here....Dang.  The generator costs more than most televisions.

[thatoneguydavid]

I have just a few questions:
do you have a measurment or esimate of the RPM of the alternator?  automotive (and most others for that mater) are designed to have a minimum of 2000 RPM to operate properly.

from the parts you have constructed i can see that the theoretical max output of your bicycle is approximately 444 watts, but have you even come close to generating that much energy with a single user? 
if so, how long were they able to sustain that level?
what was the load that was consuming 444 watts?

[pben]

A fit human can output 2/3 of a horsepower continuously on a bicycle.  So 748 * 0.66 = 493 Watts.  The problem is that is a fit person working hard.  For most people 1/3 of a horsepower is more realistic, around 250 Watts. 

The speed is a little harder to calculate.  It depends on the ratio of the bike wheel to the wheel of the pulley on the alternator,  I am just guessing but 2000RPM Should be possible depending upon what gear the bike is in and what RPM you are peddling.

[ggood]

I have a Saris PowerTap device that measures power at the rear hub of my road bike, and my maximum sustainable one-hour power is 250 watts. I'm a trained racing cyclist, so I suspect an untrained person would be able to do 100-125 watts for an hour. Assuming the generator is about 50% efficient (a SWAG), I imagine typical power out would be 50-60 watts.

Pros are a lot better; Lance Armstrong's time trial/climbing output has been estimated at 400-450 watts (he doesn't publish his actual figures, as far as I know).

[quakefiend]

In that case, I think I'll sit back, drink a beer, and let a solar panel do the work for me.  Heh.

[ddd1234]

If I am only making the bike to power the TV which of these stuff do you think I won't need?

[dmcnair]

 Pedaling at the rate used in your demo, how long would it take to charge a 50 amp hour deep cycle RV battery?

[ctonks]

 Brad, I really love this. 

We (electricpedals.com) are based in the UK and are in the same business! We recently powered an entire house for a science show. Unfortunately you can't see the show in the US, but there is a bit about it here. 

I'm now working on a mass mobile phone project for major festivals in the UK and intend to approach this a little differently. That is we've already tested charging about 30 phones from a single bike (although I think 20 is about the limit). We'll use 6x 500 farads of ultracap as a repository for times when we have more riders than phones or vice-versa. These are modular and can also be use to control voltage. i.e. once system voltage reaches 15v we add another cap etc. 

Car chargers are defiantly the way forward in terms of voltage regulation! 

Good work
Colin

[ncoded]

This is such a useful article, perhaps not 'now' but probably for the future! Would it be possible to put this guide together into a .pdf for download? Also, is it possible to boil water using a similar type method?