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Step 7Controller
The controller is an important part of the electric car conversion.
The controller is a solid-state electronic box that controls the power (speed) between the batteries and the motor.
My controller is a Curtis 400 amp peak PWM controller designed for use with series-wound motors. It can run on 48-72 volts.
The higher amperage your controller is, the better your acceleration will be. The higher voltage, the better top speed and efficiency of the car.
Also, keep in mind that amperage is also what defines range in a battery. Capacity is marked in Amp Hours, but draining a battery at double the amps will give you LESS than half the run time! Having a controller running higher voltage will use LESS amps to do the same amount of work.
What's this mean? Buy the highest voltage controller you can afford! 48 volt controllers are cheap, as they are used in so many golf carts. 100V+ controllers get expensive real fast.
My 72V controller seemed to be a good compromise of cost and efficiency. I bought it slightly used on E-Bay for $300.
Follow the schematics available through the controller manufacturer to connect the batteries to the controller and motor with heavy gauge cabling, such as welding cable, with solid, heavy-duty lug terminals on the end.
The controller requires a 0-5Kohm potentiometer as a "throttle". This could be as simple as a $3 Radio Shack part, or as fancy as a purchased, specialty part such as a Curtis PB-6
I split the difference and installed a 0-5K pot inside a free-from-the-junkyard forklift throttle control.
Run the gas pedal cable to the potentiometer, so that when your foot is on the gas, it sends a variable signal to the controller.
Update! I later switched over to running an Open ReVolt motor controller. It's the same one you can find here on Instructables at http://www.instructables.com/id/Homemade-100-HP-Motor-Controller-for-an-Electric-C/
That controller is good for up to 144V and 500amps.
The controller is a solid-state electronic box that controls the power (speed) between the batteries and the motor.
My controller is a Curtis 400 amp peak PWM controller designed for use with series-wound motors. It can run on 48-72 volts.
The higher amperage your controller is, the better your acceleration will be. The higher voltage, the better top speed and efficiency of the car.
Also, keep in mind that amperage is also what defines range in a battery. Capacity is marked in Amp Hours, but draining a battery at double the amps will give you LESS than half the run time! Having a controller running higher voltage will use LESS amps to do the same amount of work.
What's this mean? Buy the highest voltage controller you can afford! 48 volt controllers are cheap, as they are used in so many golf carts. 100V+ controllers get expensive real fast.
My 72V controller seemed to be a good compromise of cost and efficiency. I bought it slightly used on E-Bay for $300.
Follow the schematics available through the controller manufacturer to connect the batteries to the controller and motor with heavy gauge cabling, such as welding cable, with solid, heavy-duty lug terminals on the end.
The controller requires a 0-5Kohm potentiometer as a "throttle". This could be as simple as a $3 Radio Shack part, or as fancy as a purchased, specialty part such as a Curtis PB-6
I split the difference and installed a 0-5K pot inside a free-from-the-junkyard forklift throttle control.
Run the gas pedal cable to the potentiometer, so that when your foot is on the gas, it sends a variable signal to the controller.
Update! I later switched over to running an Open ReVolt motor controller. It's the same one you can find here on Instructables at http://www.instructables.com/id/Homemade-100-HP-Motor-Controller-for-an-Electric-C/
That controller is good for up to 144V and 500amps.
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http://www.instructables.com/id/Homemade-100-HP-Motor-Controller-for-an-Electric-C/
for a go cart conversion? I cant afford any other controllers.
That's the controller that's in my car right now.
All the costs, help, and info are right there.
i didn't see you say anthing about that
I have run it as high as 144V with no trouble at all.
Heat might be a problem with a smaller motor. This one is very beefy. Solid and well built. No trouble whatsoever.
In general though, if you are overvolting a motor - keep an eye on it and the temperature.
I have been considering either a car or motorcycle conversion.
Also have you considered converting your headlight to H.I.D. projectors? They pull less power and the other light bulbs to led?
How do you shift the 5 speed with no clutch; that wasn't mentioned?
Cars top speed on the 72v or the 144v your tried it at?
The top speed at 72V is 45mph and 75 mph at 144v.
I also have a motorcycle that I converted to electric.
HID headlights are expensive. The lights I have already work fine.
The tail and turn signal lights are LED.
The exact range of the car has been kinda hard to nail down. My original estimates were 30 miles at 144V, and 20 miles at 72V.
Real world driving has been a bit less than that. I am driving on USED batteries. The limiting factor is the worst battery in the string. I finally got a small battery monitor that shows the voltage of each battery individually. That will help me track down the worst battery, and trade it out for a better one.
I am using same SMD LED with some circuit and it is working good.Use batteries of VRLA siliocon gel based batteries..
Do you have an Instructable or other information on making LED headlights? I would love to learn how to build some, I just need the time and money!
I'm probably outdated though as I've stopped going to digg.com for my information. I find that its too mainstream to be useful or interesting.
Either way when I originally hooked up this cree LED for testing I was stupid enough to think it would be a bright idea to look directly at the LED itself... Trust me dont do that even for a second while they are running or you will end up with a temporary blind spot in your eyes for more than a moment. (took about five minutes for my eyesight to return to normal afterward, I was quite nervous for a while there)
All in all they seem to run rather well on just 5v usb power.
Been following your ibles, they are pretty damn cool. A friend of mine has an idea to convert his GMC Sonoma p/u and I've forwarded your ibles to him.
As for LED Headlights, I saw this one sometime last year: http://www.instructables.com/id/DIY-LED-car-headlights!/
Might be worth checking out.
Hope to follow your footsteps some day :)
i have heard storys of people destroying their motors
http://www.diyelectriccar.com/forums/showthread.php/need-help-tell-many-amps-and-38479.html
I have pretty much just been running it at 72V.
It works great - no problems whatsoever!
If I was running it at 120 or 144V, I'm sure I would need to advance the timing.