So I'm trying to figure out how I can make something you can attach to a bike that charges a battery and in turn a phone.
To even get started, what motor could I mount to the bike that would allow it to charge a battery at something like 5v and 2a, while buying spun by the wheel. I get the voltage regulator part but I can't figure out what motor I should use or how I'm even going to mount the fucker
Thanks for your time
>>993170
dynamo
>>993170
Glue a solar phone charger to it
>>993170
Back in the 70s and 80s before LEDs became so good bike lights that used a generator spun by the wheel were commonplace. I'm sure you could still find one.
http://www.amazon.com/Factor-3-Inch-Bicycle-Generator-Light/dp/B003H3Z8CW
>>993170
>So I'm trying to figure out how I can make something you can attach to a bike that charges a battery and in turn a phone.
Ordinary brushless motors will generate electricity when spun. You just need to add some diodes to get the AC changed to pulsing-DC.
The easiest example to use is stepper motors, because the two windings are totally separate from each other (they aren't connected electrically). If you attach an LED to the two ends of a stepper motor and spin the motor by hand, you will see the LED light up a bit. Both of the windings need a separate rectifying circuit (four diodes).
,,,,,,
Also We Note: LEDs are "diodes", but they are made to light up--they aren't made for rectifying use. Most LEDs can only withstand <5 volts in reverse before they blow.
You need a real diode for rectifying, such as a 1N4007. It is pretty small but is still rated for 1 amp forwards and 1000 volts reverse bias.
For a bicycle generator, you would want a stepper motor that is direct-drive and small, like a nema-11 or nema-8.
The little "can"-type stepper motors (that come with the cheap ULN2003 driver boards) cost less but they have plastic gears inside that will quickly wear out and break if they are stressed hard at all.
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RC-style brushless motors will generate electricity when spun too, but they are triple-phase motors wound in a "Y" configuration. For using them as generators, it may work better to re-wind the three phases separately and give each its own rectifying circuit.
picture is unrelated
>>993237
>Back in the 70s and 80s before LEDs became so good bike lights that used a generator spun by the wheel were commonplace. I'm sure you could still find one.
Bicyclefag chiming in---
In Europe, most people with bike lights still use dynamo lights because that way they never need to bother with changing or recharging batteries.
Son and Shimano make front wheels with dynamos built right into the hubs; these are pretty common on nicer utility bikes in Euroland.
The better dynamo lights even have a super-capacitor in them now so that they will keep running for ~30 seconds when you stop at intersections.
In USA-land you can still buy bottle dynamo lights on Amazon; they don't cost much and most have LEDs now but they are still built pretty poorly. The Euro generator setups cost $100+ and work much better.
>>993244
Also Euroland bicycle fag, everyone I know uses battery powered lights now.
>>993240
I believe that ESC's charge their capacitors when in braking mode, but I could be wrong. Replacing the cap for a powr regulating circuit might work.
>>993245
For me it's mixed, and it really doesn't make a fucking difference which you use
>>993170
https://www.youtube.com/watch?v=2wQikiHF7WA
>>993244
You can buy hub dynamos everywhere now. I wouldn't bother with bottle dynamos.
>>993499
>Trouble with the things is they're unreliable as all fuck
Hub dynamos are very reliable, and have negligible drag. You can buy ready-made USB charger attachments, and some lights come with a charger built in.
>>993478
This is not gonna give enough power.
Unless it's on top of a speeding bike.
http://www.popsci.com/diy/article/2013-04/amp-your-ride
>>993170
https://youtu.be/2wQikiHF7WA
lmao just clicked this, and thought of this thread, so had to come back to post it. you could also, take it one step further, clip off the fan blades, and extend the arbor somehow, add a rubber grip, and have the grip rub against the outer rim of the bicycle, you wouldn't need to pedal so fast.
>>993173
this.. these things been around forever.
>>993170
>So I'm trying to figure out how I can make something you can attach to a bike that charges a battery and in turn a phone.
here ya go bud (pic related)
point blue end at sun,
charge phone.
doesn't even need to take power off the bike
it's like this shit just comes out of the sky or something
>>993666
It's also like that shits fragile, only works when it's sunny, expensive, and has horrible efficiency
Also this is /diy/ go home
