Home Brew Challenge for Electric Geniuses (make a DIY electric motor controller)

[MetroMPG]

Waxy, the motor's not going to be at risk. (Unless the controller fails full on and you then declutch or shift to neutral, over-revving it to kingdom come - KA-BANG.)

I'd love for someone to come up with a workable, open source controller that a noob can build for less money than a commercially made version. ( Should we say "a used commercial" controller to be realistic? )

What will be the specs? Input voltage, current limit?

I'll bite: to the builder (you've got to build it!) goes a free Ecomodder sticker!

[WaxyChicken]

Whoo Hoo!


Once the equipment is collected then I'll post up the info with rules and, under Metro's guidance, we'll begin the official competition.
(unless there is a Different direction you wish to take this, Metro.)

I guess it would be The EM X-Prize #1: Homebrew Beer Budget Controller.

[WaxyChicken]

BTW, to be the most useful controller for all the members of the community, does anyone have any suggestions for requirements before they are made official?

[WaxyChicken]

Proposed requirements #1:
(these aren't the rules just the requirements for the controller)

A homebrew controller that meets these requirements is what we're starting with.
Does this seem reasonable to those considering competing?

Requirements LINK

Also, is there any concern with somone using automotive car batteries (usally start at 450 to 550 CA) instead of 6v or 8v batts that run around 200A?

give feedback on your thoughts.

[TomEV]

Here's a link to a controller schematic... Some components don't have a value, but might be a start...

http://www.qsl.net/w8rnh/curtisschematic.pdf

[LibbyMetro]

I dont know if I've ever felt dumber than right now

[Coyote X]

that makes things much easier that one is using 35 IRF640 mosfets

http://www.ortodoxism.ro/datasheets/...cs/mXtvwts.pdf

for the datasheet for that type of mosfet.

18 Amps continuous 72 Amp pulsed. So without a cooling fan on the heatsink I would assume they would stay under the 11A continuous current. That gives 385A for the current with a capability of handling 200V input.

Seems pretty simple to build in theory, but getting the wires all together and attached to a large enough heatsink could be a real pain

As far as the pwm control in that schematic I think the guy who made it loves op amps. I would probably try and make it a bit simpler for hobby type stuff. Maybe use a 555 timer would be simplest but using a microcontroller would make the circuit way easier to build but would add having to build/buy a microcontroller programmer ~$25 to buy a basic one. Buck or 2 to build one. The only other thing I see in that circuit is a thermal sensor to monitor the mosfet temperature. Easy enough with a microcontroller and could even add a cooling fan in there. Also it could activate a contactor switch when it is at full power to get rid of the mosfet resistance when full power is needed. I still think a manual disconnect switch would be required for any type of controller in case of emergency though.

I could probably modify my nitrous controller and use it for the pwm driver that way it could be done with a 4x20 lcd and buttons to program the controller. If I ever get enough time free to dig out that old setup and figure it out I might try and build something.

[WaxyChicken]

Originally Posted by LibbyMetro

I dont know if I've ever felt dumber than right now

[WaxyChicken]

Oh, wait, there is something i can add:
LINK: 555 schematic

Now other than CoyoteX's brain fart, anyone else feel they have a shot at this project?

[rbhollabaugh]

I've built a few PWM motor controllers for smaller (<20Amp) DC motors. That's not too hard. Building a controller for a car sized several hundred amp application would be difficult and could pose a few safety hazards.
If it were me I'd use the time that would go into building a controller from scratch and make money at some part time job and then buy a used or new commercially available controller.
Building the controller you have in the schematic would probably take a week of your time + parts. Can you make enough money in one week to buy a controller?

Rich