too many amps ? too many volts ? i feel like a dummy

Discussion in 'Electric Bicycles' started by thescooterguy, Jan 13, 2009.

  1. thescooterguy

    thescooterguy Member

    ok after burning up two controllers and a motor , i putt a fuse in the line , i can be stubborn , this is a trike Ive been building . it was supposed to be a 36 volt 12 amp pedal assist . sparing you all the details of the magic blue smoke . its like my motor is pulling too many amps . i even disconnected two batteries and tried running it as a 12 volt 12 amp system still blew fuses . i just gave up on the controller thing and went to a simple toggle switch rated for 36 volts , actually more . i have the positive line going directly to the motor and the negative wire has the switch in it . i hit the switch and the fuse blows . i just used an in line fuse system for a car , used the blue one #15 . any hints , clues , or help would be very appreciated..

  2. bluegoatwoods

    bluegoatwoods Well-Known Member

    There's a guy here named duivendyk. When he sees this, he'll have some useful info for you.

    In the meantime, I'll take my shot.

    I think your problem is amperage, not voltage.

    Does this happen under no load? If you lifted your drive wheel and turned on your motor would it burn things up?

    If the answer is no, but it does burn up when you load it (trying to ride, for instance) then your wiring and acessories are not up to the current, or amperage, that your motor draws when working hard.

    But I'm afraid I can't carry it any further than that. But someone will come along with something better.

    Good luck.
  3. thescooterguy

    thescooterguy Member

    yes i think its the initial load to get it started , and you are correct if i jack her up so there isn't as much load on the motor , it goes good , as for system lights and things don't have em . its lust a simple 3 battery system with 10 gage wire . the motor has 12 gage wire its just a bit smaller then the wire i used to .
  4. bluegoatwoods

    bluegoatwoods Well-Known Member

    I'm on thin ice here. My knowledge is totally what I've picked up by reading.

    But I would think that 10 gauge wiring would be good enough for quite a load.

    It would seem that your controller is not up to the power (volts X amps) that it's getting.
    They must be rated; X watts, Y watts, Z watts.

    If you have some way of knowing or measuring or calculating how many amps flow through under load and multiply that by the voltage, you'll have the answer to how many watts your motor is using. Then get yourself a controller that's rated, maybe, double that.

    But who knows what I've overlooked here? someone will come along with more certain info.
  5. thescooterguy

    thescooterguy Member

    its winter here in Oregon , i was trapped in the house for 10 days , i normally build bikes with two stroke motors , but i needed a project i could do in the living room . because the shop was toooooo cold . someone had given me a vintage trike earlier in the winter and i had a bunch of electric motors in the shop from electric scooters i had converted to gas last summer . just thought i would putt one to good use . here is a b4 and after shot . i took that thing apart down to the spokes on the hubs , so i could get the rust off the rims . shined up the chrome and painted and mounted . all in my living room . 10 days of snow what is one to do .

    befor and after
  6. azbill

    azbill Active Member

    she cleans up nicely !!!
    (as my gran used to say about me :))
  7. duivendyk

    duivendyk Guest

    I suspect you have may well have a short in the motor,does it turn freely when idle?Try a 30 Amp fuse preferably the slow blow variety (the screw-in type for instance) and try starting from a 12V battery under no load conditions,alternatively use a 20/30 Amp breaker like those used in house service entrance panels.Has the thing ever shown any inclination at all to start running?.Has it ever worked?If you have auto12V headlight lying around you can try putting it in series with the motor to get some resistance in the circuit and see if it starts to run when you apply power, this will serve to limit the start current.The light should dim once the motor gets up to speed,if not and it does not run, it's shorted.If it's not shorted put a switch across the headlight to short it out and apply full voltage to the motor.Good luck.
  8. thescooterguy

    thescooterguy Member

    yes you were correct , the motor had a short in it , i replaced it and also went and got a voltage meter . to check everything , the guy at auto parts store was helpfull . i noticed that currie e bikes used a 45 amp fuse . i was useing a 15 amp and uder a load hat motor pulls more than that . i upped it to a 40 . and got my wiring cleaned up . added a nice battery box that has a tool tray , and mounted charger connector to the side . took it for ride its nice,
  9. duivendyk

    duivendyk Guest

    Super,problem solved!
    Last edited by a moderator: Jan 15, 2009
  10. atreeenurse

    atreeenurse Guest

    Can I use a 75vx40amp battery on a bike with a 25 amp controller for distance. Or will I burn something up?I need 140 mile distance on level ground to commute daily. Also I live in florida. Hot. Is this too hot for e bike. Thank you
  11. rainmaker

    rainmaker New Member

    From everything I have researched the answer is yes. The most the controller you are using will ever draw from the batteries is 25 amps. So you are perfectly fine using that setup as long as the motor and the controller you are using are both rated for 72 volts. You can use more amp /hours to gain distance. It' s not the amps that will fry your controller it's using more volts than your setup is rated for. hopes this helps.
  12. KCvale

    KCvale Motorized Bicycle Vendor

    Well, you might be able get the 70 miles to work and plug the battery into the charger for the 70 mile return trip and plug it in again, but when we talk that kind of miles go with a 4-stroke shifter.