# Build it !?



## st51 (Apr 20, 2009)

I happened to get a motor with built in controller (for a scooter) that I am planning on rigging to a bike. I got mine off ebay about a year ago, but wouldn't one of these scooter controllers work for your project? There are some rated at 36v up to 500watts. (under $30 bucks??)


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## carl2.0 (Jun 26, 2009)

Wow nice price, this would be perfect and time saving but Im currently residing in the Caribbean which makes shipping a bit tricky...


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## ngrimm (Oct 19, 2007)

I personally recommend the lm3524 circuit listed here: http://www.diyelectriccar.com/forums/showthread.php?t=13763&highlight=3524

I have built several of them and they are pretty simple to put together and work very well. Same or fewer parts than a 555 design with way more features. You could eliminate some things for now like the throttle ramp, shunt, shutdown even current limit if you wanted. Then as you get more familiar with the design you can add more. Incidentally, the one I built for my Ninja has fifteen 62a 200v mosfets for 900+ amps peak and I am running it on 72 volts for now.


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## carl2.0 (Jun 26, 2009)

Nice thanks, Ill havent this one, havent done electronics at this level but im guessing if I show it to someone who has theyd b able to show me wat i do n dont need for a simple controller


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## ngrimm (Oct 19, 2007)

Forgot to meantion, you can get a breadboard and a jumper wire kit at Radio Shack to plug all the parts into without soldering anything. Makes it really easy to make changes that way. Of course the mosfets and freewheel diodes need a heat sink. Once you are satisfied with how it works, you can solder everything to a prototype board which is also sold at Radio Shack. And no, I don't work for Radio Shack


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## Amberwolf (May 29, 2009)

from old thread said:


> Now Im at that dreaded section the controller ! Its no surprise that I cnt get one here so Ive been doin a lil research to build one I think Ill go with a PWM ...seems the easiest right ? Can anyone steer me in the right direction here and also I know this is a noob question but what is the advantage of controller/pwm over a variable resistor ?


If you try to use a variable resistor to control that much power, you will need one that is bigger and heavier than your motor, and possibly your battery.  Otherwise it will get so hot so fast that it could melt or burn up, depending on the type. 

I have a very high power (1000w?) stage lamp dimmer here, and it is extremely heavy and bigger in diameter than my spread out hand! It's just a giant wirewound potentiometer, basically. I wouldn't recommend using one for motor control. 

PWM is very efficient, with little power loss in the controller, especially at lower voltages like what we use on bikes, typically.

It is also easy to make, even with just transistors (lots of wiring, though). If you have an electronics junk source, especially for industrial stuff, you can find LM339 quad comparators in a lot of things, including industrial power supplies (which may also have giant MOSFETs and diodes you could use). 

I have the very basic schematic someone drew up of my ScootNGo controller, which worked for my radiator-fan bike just fine, with the larger MOSFETs and driver transistors I used (it would not have worked as it originally came), but I did no actual circuit modifications, just replaced small-power parts with bigger ones. 

After I find it, I can scan it in and post it here--it's a hand-drawn schematic, but it is usable to build and/or troubleshoot the controller from, if you know electronics. 

If you do not, you'll probably need a more direct visual representation of how the parts get connected, and that would take some time for me to draw up, of which I have little right now (trying to make ends meet). 

I have posted the same reply to your old thread, in case you miss this one. 

FWIW, it might be a lot easier to get relevant replies if you kept your project in a single thread, instead of starting new ones. Then others can see what you already have, what you know, what limitations you have, without you having to re-explain yourself every time. 
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ECIGARETTE 123


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