OK guys, I would like some help building a trans brake controller for my race car. The trans brake operates off of a 12 volt solenoid that the controller will provide the ground. It will need to be able to handle 20 amps for 10 seconds or so. Basically I will set the brake, and then allow the car to creep forward every time I press another button. When I release the set button, the brake will fully release and allow the car to launch. My assumption is that I will use a PWM output to control a transistor to drive the solenoid. While set it will be at 100% duty cycle. While creeping it will be maybe 50% duty cycle. Can somebody recommend a pre-made transistor board that will operate off of the arduino and handle the load?
I don't know the answer but I think it would be worth changing your Title to something like "What do I need to control 20 amp load with PWM?". If you modify your original post you can change the Title.
Find a logic MOSFET with 5 milliohms or less on-resistance and use a heatsink.
A MOSFET driver chip might be wise if using PWM at high frequencies (above 1kHz).
My assumption is that I will use a PWM output to control a transistor to drive the solenoid. While set it will be at 100% duty cycle. While creeping it will be maybe 50% duty cycle.
"PWM" suggests analogWrite() and a ~500Hz frequency which a mechanical solenoid is not going to be able to keep pace with -- given that these trans brakes are either on or off and nothing in between. I don't think you're going to want to pulse it more than ~10 times per second and you wouldn't want to use analogWrite() for that.
I used several of this Simple-H User Manual - Robot Power
With standalone ecus, we use a pwm output pulsing a solid state relay at 90-95% to make them "creep" slowly while they are on the transbrake.