2 Speed Fan Controller?
 

I have a dual fan shroud setup that I got from Summit. I was wondering if there is any way to control this via voltage with 2 speeds. I couldn't quite find any controller to do this with the Haltech outputs.

Derale Performance High Output Dual RAD Fan and Shroud Kits 16825 - SummitRacing.com

thewird

You could use two outputs and a set of relays with a resistor to offer two speeds. Would need a heck of wattage rating on the resistor I would think. Or you could pick up a solid state relay and use one output set to PWM fan control and have infinitely variable speeds.

Could a solid state relay handle 25 amps sustained? (when the engine is hot, like on track for example)

thewird

Yep. We have them in 40 and 100A ratings.

Hmm, I'll just get a 100Amp one then and run both fans through the one. Saves me an output for future use :). I'll wait to see if I can think of anything else I might need from you before ordering.

What frequency would it be set at?

thewird

Toyotas have used a system to provide two fan speeds by running the fans in series for low speed (each one being the resistor for the other). Then switch them to parallel for high speed. requires three relays.

You need to be careful with running electric motors at lower voltages or even with PWM. some motors don't like it and may not last long running like that.

thewird, have you done this yet? if so, do you have any pics or more details?

i'm very interested in doing the same thing with my FD.

Marco..look into Clokker's Sec gen stuff with an Efan and relays.He uses a Volvo 2 relay setup.It may be helpful.

I did and a fried the relay. I did everything correct but the power for the fans was live instead of switched like the diagram suggested so that was probably my issue. I have it hooked up with a regular relay for now until I feel like trying it again LOL.

thewird

stick to the 20B ..hahahaha!..
wiring just seems to not like you!.(whats that smell??)

i dont understand how the live power wire would make the relay fry.

these get wired like a standard 4 pin automotive relay, right? with the high current in/out and the trigger

It's not a mechanical relay. It relys on on a high and a low to open and close the relay. You have to use a pullup resistor which comes with it. I'm guessing the live power wire kept something active after I turned the ignition off which wasn't supposed to and overheated it. I think the relays are designed for A/C current but we've adapted them to DC current using the pullup resistor.

thewird

I am building my current setup utilizing two of these:
30amp DC pwm fan controller.
30A Motor Speed Controller (PWM) - Cana Kit

they also offer a 50amp version:
50A Digital DC PWM Motor Speed Controller - Cana Kit

The nice thing is it doesn't require a pwm input. standard reference voltage input, so most outputs from any ecu could be used, or even a simple thermosensor of some sort with a signal conditioner for fully automated function. And it would be easy to wire in a bypass switch to be able to switch them on full when you wish.