DC Controls Delta Fan Controller
I finished the install a short time ago and all I can say is "wow"! This blows away the Derale/Hayden/Troyer/Torq style controllers (they are all of a similar design, with different rated internal components). Unlike a traditional controller this one doesn't use a relay, which alleviates the high surge (often in the hundreds of volts) when the relays first close.
Failure of these types of controllers is common, and I found the solution was to put in 1 amp clamp-down diodes on both the negative lines and the A/C relay line, but I still wasn't satisfied with it. The fans were either all the way on (sounding like a Honda) or off. Same with the A/C. I would what my coolant and cylinder head temps see saw every time the fans kicked on.
Well, the DC Controls solves that. The installation is even easier. It uses no relays and uses pulse control to turn on and increase fan speeds. The fans come on at 10% speed and increase only if they cannot keep the temps down. Unlike other controllers, the Delta puts the temp pickup at the outlet side of the radiator instead of the inlet side. This lets it monitor if the current fan speed is too high or low and adjust as needed. When the A/C relay kicks in the fans go to 50% speed.
Its 65 degrees here and I couldn't get it hot enough in the driveway for the fans to come on anywhere near 50%. The temps stay rock steady within a few degrees. You can't hear them at all unless you open the hood and listen (note these are Troyer's specially wound e-fans). Wow! I'm going to use my old Troyer controllers for an intercooler fan and transmission cooler fan.
Hayden/Derale/Troyer/Torq:
Controls up to 2 fans, relay driven (on or off), with A/C switch and ignition on/off. Temp range varies between about 135 to 220. Inexpensive but prone to problems. They can get very hot, to the point where they become "gooey" and you can pull the wires out. I found this out by mistake, trying to replace a relay when the unit was hot, the entire relay guts pulled out. Plus too many instances I've seen on the Internet where surges cause either the controller or relay to blow. I had a situation where I pulled into my garage on a hot day with the fans going full blast. I left the ignition on for about 30 seconds to cool down the engine and suddenly smoke started pouring out from under my hood. I opened the hood and smoke was literally shooting out of a hole in one of the controllers (looked like a tornado!). I was really lucky I put the fuses in an easy to reach location because I turned off the ignition and it kept burning. I pulled the fuses and it stopped almost immediately. I solved this problem when I put in another controller and installed "clamp down" diodes to keep current spikes from going through the system.
Flex-a-lite VCS:
Sets fan speed from 60% to 100%, depending on built-in fan thermostat setting. Thermostat range: 155 - 220 degrees Fahrenheit. Directs fan to run for 30 seconds after vehicle is turned off. A/C turns the fans on 100%. Very nice unit. Only thing I don't like about it is that it starts off the fans at 60% rather than a lower speed. I wanted it to be quiet when I'm at a light.
Spal Multi-speed:
Varies speed much like the DC Controls unit does. Controls each fan independently, turns both on when A/C is turned on. Uses OEM temp sensor. Drawback was it maxed at 30 amps so I couldn't use it for dual 16 inch fans. If it had a higher amp rating this would have been my first choice.
DC Controls Delta: already noted it's features. Major drawback was the high price, but given how many relay style controllers I've been through I decided that I was going to get what worked best for my needs, not based on price.
I got the 50 amp Delta version. The Flex-a-lite was my second choice, but I wanted something that could run the fans at a much lower speed, though it does have the 30 second run feature which I thought was nice. The 30 second run feature is useful for intercooled applications but I'm going to use a separate temp controlled fan on the intercooler that stays on after the ignition is off. I have an old diesel turbo cool down timer for this, which supplies a constant 12 volt current for whatever amount of time I set (30 seconds to 10 minutes). I don't think you can go wrong with either a Flex-a-lite or DC Controls.
I took photos and will have an install article up next week.
One thing I don't like about the DC Controls unit is the two connection points for positve power (input and output), is that they are exposed. If you are working under the hood in that area it could be very easy to hit it with a wrench and short it against a ground. I covered both of those with "liquid electrical tape" to prevent this from happening.
According to DC Controls the mean time between failures is in the 10s of thousands of hours at 170 degrees and over a million if you can keep the unit around 120-130 (not sure of the exact temp, have to read their site again). I plan on adding heat sinks to mine this weekend since its located near the front passenger side of the engine bay, near the hole in the radiator support where cold air comes in.
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I've been running my FAL setup for nearly 5 years now and never had a cooling issue with the factory charging system. I did add one feature to it though, I wired the ignition trigger through an RPM switch so the fans don't run at higher engine speeds. This keeps the fans from running while driving at speeds above 35mph, on the road and when I make a pass.
If they do come on, I'll consider what you're doing, I believe I may be able to control that through the PCM on my truck. It has electric fan controls in the tables (turned off), and if the PCM wiring harness has the pin-out for fan on/off I'll turn on the tables and have use that pin to trigger the ignition on/off line to the Delta controller. If the PCM doesn't support it, I'll use an RPM switch. What are you using for your RPM pickup and switch?
Considering that companies like Flex-a-lite supply e-fans for OEM applications, the reliability should be fairly high. I don't see much out there about fan failure, but I do see a lot out there about relay type controller failure (which is why I switched to a non-relay controller).
I use a normally closed contact off of my BBK Ignition box (part of an ignition system that I used for spark control before I got my SCT software). If you have the ability to control the fans through RPM and MPH then that would be the ideal way.
I ended up getting a SPAL controller. It's PWM and starts the fans at 60%. It also has a speed sensor function where you can set them to stop at any speed, which is nice. The second fan is turned on by a separate relay at 100%, but doesn't start unless the first fan is at 100% and still can't cool it. We'll see how it works!










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