Design Custom Staton FD Bike, GX35, Electrical Enthusiasts Required for a Generator

Discussion in 'Photos & Bicycle Builds' started by Friendlyfire01, Nov 21, 2015.

  1. Friendlyfire01

    Friendlyfire01 New Member

    Hi there! For my first post on, i'm shedding the anonymity of the Internet; my name is M! Yes, that letter really is in my name! Yay trust! Jokes aside, and to come, :jester: I'd like to ask for a great deal of help from the community here.
    So, I would like to build my significant other a motored-bicycle for her commute to work. Living in CA, laws are tight, and confusing***, and I've settled on doing some pretty out of the box modifications. Because the engine and mount are so God-awfully simple, I've decided the first thing I want to tackle, is the planning of one of the most important aspects of this motored-bicycle:

    • Build generator using permanent magnet 36w motor mounted to rear wheel, and appropriate 'shaft' size will be taken into account to maintain optimum RPM @30MPH
    • Regulate voltage to 12V with this LM2596 Buck Converter or something similar for added amperage
    • Find a charger for the smallest 12v battery I can find; or can the buck converter charge off of the output line? what about overcharging?
    • Wire standard automotive lights or homemade LED mounts, including headlight, taillight, brake light, and maybe turn signals.
    • Install controls for lights, on/off for headlights, and a simple on/off switch to turn the taillight into a brighter brake light. room for more gracefulness here, like everywhere else. but a lot here.. will definitely be needing help tracing out the circuits for many of these.

    I'll be adding to this post as the idea turns into the real thing, but for now it's important to me to understand the theory and design of the electrical harness and generator. The lights effectiveness very important to me, as her safety is paramount. This is the reason for the relatively high wattage PM motor and some very, very bright lights :cool:

    ***CA motored bike vehicle code 406b is easy enough to understand. however, kings county has ordinances, and police have appeared in news reports reminding motorists that they must have a left-hand mirror, and proper road lights to operate here legally.

  2. KCvale

    KCvale Motorized Bicycle Vendor

    That little 35cc engines only puts out 1.2hp, 895 Watts.
    It needs every watt to hit 30mph.
    A constant 35W friction and power draw from it will really take toll on performance, especially from a dead stop.

    But, if you want to do it anyway look at this system.

    I however find trying to power the bike and generate power from a little gas engine silly when there are cheap and reliable 8.4V LI LED light systems for ~$25.

    Those CREE T6 LED's are simply amazing, 1200 Lumens.
    The little LI pack puts out 50W, 6A @ 8.4V and whole system inducing charger is less than a pound.
    Get a second battery to keep charged and swap them in seconds.

    There are several dozen vendors of these but I like this one for the 3 light settings.
    High, low, and intense strobe.
    Next to good brakes and a helmet I find daylight riding with the strobe on is the most important safety feature you can add.

    Every wreck and close call I have had has been a driver cutting across my path because they either didn't see me, or misjudged my speed.
    A bright strobe gets everyone's attention and the result is staggering.
    Instead of me panic braking, the cars do ;-}

    I won't ride without one and sure won't let anyone else here either.
  3. Friendlyfire01

    Friendlyfire01 New Member

    Unfortunately flashers (except turn signals) aren't allowed on motor-vehicles around here. I must rely on bright lights to do my bidding, hopefully convincing people I'm on a scooter, so they stop.

    I find your first claim really interesting, and must find out whether parasitic drag will play a crucial role, or if simply peddling from starts will allow the setup I've laid forward. If it turns out the little gx35 can't push my 110lb spouse up to 30MPH with the addition of a generator, I will probably reevaluate my lighting to an 18650 build.

    EDIT: I should probably add, since I haven't, that there are no hills whatsoever around here and she doesn't mind peddling at all.
    Last edited: Nov 22, 2015
  4. skyash

    skyash Active Member

    One man invented a dynamo in the front forks 10 watts
  5. Friendlyfire01

    Friendlyfire01 New Member

    that's something i'd not thought of, if I find a bicycle with a front basket I could easily limit 90% of the wires to there.
  6. KCvale

    KCvale Motorized Bicycle Vendor

    They are legal on bicycles and for good reason, to make you easier to be seen and safer.

    Pedaling sure helps and I'm sure it will go, at what cost is the question.

    Drag is directly proportional to the amount of power you want to convert and there is always a loss.
    You loose power from drag getting your wheels to spin.
    If you want to convert that again into electricity you have drag losses again.

    The more of it you convert to electricity (Watts), the higher the drag because generating power takes power.

    The only free power source you have on your bike is re-gen braking and the sun.
    But, you need drag to stop, this is usually done by friction with brake pads.

    Re-gen electric hub motors however do this by the drag you get by converting that momentum to electricity and re-directing the power to the battery to store.

    The more ya draw, the higher the drag, hence the braking effect.

    That makes things much easier ;-}

    If you want to charge an on-board system and keep your power, just make a power generating brake system to help.

    Like a brake lever, but you pull it first and if it's not enough stopping power, then pull the friction brake too.

    Actually I am kind of liking that idea.

    It would have been a good idea back when I built my 2-stroke shifter with the programmable fully automatic NuVinci Developers Kit CVT hub.

    It needed a 12V battery to control the servo and electronics so I tried generating power from wanted bike momentum.

    It was quite the journey, 10 pages of pic rich posts here.

    Food for thought for both of us.
  7. johnsteve

    johnsteve Member