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Soft start fan controllers

13K views 28 replies 14 participants last post by  crackedblock 
#1 ·
Looking for a variable speed controller for running dual fans. I am running contour fans and am having large amp spikes initially so im trying to find a reliable one with a soft start mode. I was looking at flex a lite 31165. I know the brand and hear good things. There is also an autocoolguy.com but cant find any reviews about him other than on his own site. Seems like they are made at his home or something? Im looking for reliability and longevity-i like to put miles on my car so it will see heavy usage :) hoping you guys have some good input or other options
 
#2 ·
Those fan setups for Contour had a resistor for the use of a low speed relay for one fan. The other fan would for high speed usings its own relay. I would work an idea to use a Flexolite product for your "low speed fan" and control the "hi speed" fan separatly. Fans can be hooked upped in series than parrallel for high speed control depending on controller types. The use of dual control fans is easier in the long run on the charging system.
 
#8 ·
Testing my memory from two years ago but it was early 2000's. I want to say 2002. I had thought about wiring one to come on with the controller and running the second one to come on with a switch if it got too hot. But i dont really like the thought of if i dont catch it rising and it gets too hot and causes damage. There's enough to worry about just other people on the road anymore. Everyone likes to text and drive and constantly have to watch for people wandering into your lane ect. Because they arent actually driving
 
#14 ·
The latest model V-6 Contour used both fans electrically in paraellel of each other. Still uses a low fan relay w/resistor for low fan control for both fans and a high fan relay that feeds both fans at battery voltage. "bdub4u" Set-up would the best.

As far as your voltage spike issue I would be looking at the main current carriers. The power & ground supplies to tha fans. How do have hooked up/where and approx wire size?
 
#10 ·
I have a voltmeter inside the car and when the fans kick on they "shock" the system. Everytime they comr on they kick the volts from about 15 volts to around 11-13 volts then it will kick back up to 15 volts. I have a 3g alternator on. I have also changed through multiple grounds and have tried different wire thicknesses. All with the same "shock" the more they kick on especially when its a frequent on/off on hot days the shock will bring the volts down everytime. Im afraid eventually it will drain the system entirely or burn something up
 
#11 ·
When I'm out in my detached garage the lights dim a split second when the heat pump kicks on in the main house. Same thing, and it's how these things work. If it bothers you anyway then consider setting up to turn on one fan at a time and/or a two speed controller. These will help your peace of mind but the "shock" voltage drop doesn't hurt anything. Electric motors have been doing that as long as they have existed.
 
#13 ·
Modern fans are controlled by computers and sometimes multiple relays. One of the last OEM dual speed soft start style relays people figured out how to retrofit to address your concerns is a Volvo 850 fan relay setup. I had one I was going to figure out but somebody traded me out of before I got the chance. I've yet to score another. The info is out there to be Googled. They're pretty popular. Say what you will about Volvo's being odd but you can't deny them lasting. I'd prefer one of their used relays over any new aftermarket version for reliability.

Modern fans are sometimes pulse width modulated to get past the same issues that concern you. Messing with such setups is over my head.
 
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#15 ·
I am running the Volvo 850 OEM relay, but without real world usage yet. Dual speed single 16" fan (also OEM Volvo 8/9 series). My first thought reading this was to check out what Ford did in the contour from a relay standpoint and try and use that. OEM product certainly gets put through the ringer from a test and use standpoint, I would start there.
 
#17 ·
The OEM relay has 2 separate inputs (low and high), which in my case I have the low speed routed through the FITech unit to control it, and the high speed wire I have routed to the OE factory fog light switch for "manual" control. Outside of the FiTech control component (which I was doing anyway, the fan control is a byproduct of the system) I figure I have about $9 total in my relay (2 relays JY pulled $7, a bit of wiring as part of an AAW harness). The FiTech also provides the sensor (required by the system) that provides adjustable control for on and off temps. I did buy a new factory fog light switch as mine was pretty beat up, cost me another $26.

Again I have no real world experience yet, and some of the $80-150 fan controllers look cool, with some wide ranging results (love it, hate it). I'm not suggesting that my route is the best route to take, only that OEM engineers addressed the voltage and relay concerns for the dual fans where they MUST survive a 5 year warranty period and say 10k start cycles? If it works for them I can't see how even a daily driven classic could not see the same positive results.

If you wanted to go all new, the relay is about $35 from Rockauto but you will likely have to go source the connectors in the JY (my original plan until I found lots of relays and connectors waiting for me). The fan I used was new however from RA. Hopefully firing it all up around April 1st.
 
#18 ·
I'm running the Contour 6cyl fan in my 65. I have an Autocool 85 contoller (Link). I can't say enough good things about this controller. Ground based, variable temp, dual fan capable, good to 85 total amps, soft start, 1 minute cool down, A/C and manual overrides, USA made and its built like a tank. Awesome setup.

-Shannon
 
#19 ·
Thank you all for the input and suggestions! I have it wired with 12 ga wires through a flexa lite controller model:30332. But i use it basically only as a switch that goes to two relays. I have two 40 amp relays for the fans. One per fan. So basically the controller takes no load and only switches on the fans. Shannon with the autocool85-did you use any separate relays for the fans or will the controller run everything? Did it take long to get once you ordered? And do you have alot of miles on it?
 
#20 ·
Hey guys. First time post here. I've been having the same issue you're discussing. I run a 2,000 Contour/Mystique dual fan. I trigger with a thermo switch in the top radiator hose, and that activates two relays, one for each fan. When I got the fan setup I removed the oe low speed resistor. I had assumed that the power draw with or without the resistor was the same. When the fans start the msd ignition sputters for a few seconds and the idle drops.

I run a hp ford 300, big cam, ported head, over-size valves, headers, Holley, etc.

There was some great info in the thread, but it left me with a couple of questions that I would very much appreciate if someone could answer:

1. Would using the Volvo relay/control pack stop the power surge, sputter issue?

2. If I wanted to start one fan later than the other, does anyone know how I would do that? Thank you very much.
 
#23 ·
I have been looking at this fan controller. It turns on one fan first and then the second fan comes on 10 seconds later. You can buy it through summit for $66. Seems like a well built product at a good price with control of the temperature that the fans turn off and on. Plus having one fan start before the other reduces the power spike seen when dual contour fans start up.

https://daviescraig.com.au/product/digital-thermatic-fan-switch-12v-24v-0444
 
#21 ·
Idk anything about any of the previously mentioned fan controllers, but here is what I can think of...

A. Install a higher amperage alternator and hope it handles the additional load/surge of the two fans coming on at the same time.

B. Use one temperature switch to activate one fan through a relay. Then add a manual switch to turn on the other fan, again through a relay, when you feel necessary.

C. Use two temperature switches. One to turn on one fan at 200F and the other at 205/210F.

D. Use one temperature switch to turn on both fans but use a timer circuit to turn on the second fan 20-30 seconds after the first.
It’s a bit more complicated but any electronics enthusiast can figure it out. Durability however, is more questionable. Again, use relays.
 
#22 ·
Thanks for the reply. I guess I'm a bit frustrated and tired of trying new triggers and relays, etc. I don't wish to upgrade to a higher amp alternator. 130amp alt to run a set of fans that draw 25 amps running must be ample. Anyway, it's where I draw the line. I may try to change the thermostat and use a different temp thermo bmw switch with the volvo two speed controller, and see how that does. Or, I may just chuck it all and go with a nice soft start autocoolguy controller. I noticed on his site that he has an interesting temp probe that sits on the outside of the lower radiator hose attachment fitting. Interesting.

Anyways, thanks
 
#29 ·
That is true. I have two of the V. relay packs. I have tried them. The problem, however, is that the Volvo pack is made for a two speed fan. It is not soft start, so it does not prevent the spike on start up.

You guys have posted links to some very inexpensive controllers. They are so inexpensive that they worry me about durability and longevity. Did I miss any mention of warranty? My bad if I did. I simply could not install an unknown controller like those and feel good and confident about it lasting. But thanks for the links and the looks see.

I called to autocoolguy, since he is up the road from me. He warranties all his products for a full year. Although my Contour set-up spikes way up there, he recommends using his 55 unit. It is fused at 60amps. My fans draw together just under 30 amps, and since his unit is soft start, I will not get the huge spike. I'm considering using this system.

On a side note: I have noticed that since installing my efan system, I have to change my battery every two years like clockwork, or I pay the price of the system shutting down. My last battery was warrantied for 3.5 years, and died after two years two months. Converting back to a conventional fan would save a lot of trouble and expense. It may not be as cool, but I guess I would have saved about $1,000 and untold hours of work had I stayed with the oem fan with zero fuses, contacts, relays, over-sized alternator, thermo switches, etc.
 
#25 · (Edited)
That setup seems like it's for actual dual speed fans. While the contour fans were dual speed in a sense they are not wired like a dual speed fan with two input wires and a ground. They only have one input and a ground. They were wired by two feeds one that went through a resistor on one that was full 12 volts. Both fed into the single input on the fan. I think you could make it work on a contour fan if you used the OEM resistor which @crackedblock states he doesn't have.
 
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