Dual electric fan wiring.

[747mopar]

Never ran electric fans so I thought I'd see if any of you had any ideas to share. I know exactly how to wire it but was just curious to what the best methods are for operating it? My way of thinking is just put a thermal switch in that turns it on at 200 and shuts it off at 185 (I have 180 stat). It will have A/C so do I put a trinary switch in that turns the fans on whenever the A/C is on? Also thought it might be nice to have a manual override for on and off as well? Just trying to think it through and save myself from redoing anything.

As far as wiring goes I'll be coming off the battery with 10 gauge wire to a 30 amp breaker (fans are 28 amps) then to 2 relays (1 per fan) that will be triggered by the temp and trinary switch wired inline or at least that's my thoughts as of right now.

 

[aldal]

I will be watching as I also need to make a plan for mine. :eusa_think:

 

[coloradodave]

This is a slick fan controller. It allows you to adjust the on-off temperature and gives you an indicator lamp hook-up and a manual over-ride. I bought it from Speedway Motors as I didn't see it anywhere else: Electronic cooling Fan Control:
http://catalogs.speedwaymotors.com/publication/?i=233552&p=218

 

[Crackedback]

With 28 amps of draw, IMO, you don't have enough overhead rating with a single 30 amp breaker. I'd run a 40 amp.

You could run it as described. Hard wiring in a switch to manually control is not a bad idea.

Most of the thermal switches are to ground.

I did my car using a similar approach, except I have one fan on a manual switch and the second on a thermal.

 

[747mopar]

This is a slick fan controller. It allows you to adjust the on-off temperature and gives you an indicator lamp hook-up and a manual over-ride. I bought it from Speedway Motors as I didn't see it anywhere else: Electronic cooling Fan Control:
http://catalogs.speedwaymotors.com/publication/?i=233552&p=218

Your link shows multiple controllers? I was looking at these at Summit just didn't know if it was necessary, would be nice to be able to adjust it.

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With 28 amps of draw, IMO, you don't have enough overhead rating with a single 30 amp breaker. I'd run a 40 amp.

You could run it as described. Hard wiring in a switch to manually control is not a bad idea.

Most of the thermal switches are to ground.

I did my car using a similar approach, except I have one fan on a manual switch and the second on a thermal.

You may be right, they don't specify if that's the running amps or the starting amps? If it's starting amps a 30 amp breaker should be fine but if it's running amps I'll likely need the 40 amp breaker.... I'll just put the 40 in and forget it.

Yes, thermal switches are to ground which makes the wiring even easier. I'll be using the ground terminal to trigger the coil on the relay and have the positive terminal wired to an ignition on source.

 

[Sixpactogo]

I too am interested in the best way to tackle this issue. I have the two electric fan setup on my 68 Charger. My car has a 6.1 with A/C. I am currently running both fans from the engine temp sensor which I believe turns the fans on at 200F. They are noisy and drop the temp real fast so probably only need one. I do not have them set up to come on with the A/C and have wondered if I need to. My 300C and LHS do not turn on the fans when the A/C is turned on so I hope it will be ok.
I am using Crackedback's relay setup for my headlights so I have 4 relays mounted on the core support. Each has a 30A fused source. I ran a 6 gauge wire from the alternator to a 5/16" buss stud mounted on the core support, then ran individual #10 wires to the 30A fuses from it. I am sure I have ample current capacity but may need to add one more relay if I need to run a fan with the A/C. I will be watching this thread as well.

 

[747mopar]

You shouldn't need another relay I don't think, my thinking is if your relay is being switched on and off by the ground from the thermal switch than why couldn't you ground one terminal of the trinary switch and then tie the other terminal right into the thermal ground?

 

[Yatzee]

There are a couple controllers on the market that offer features that make installation a "one time" thing but you have to posses a bit of electrical ability to install properly. I use both - one on my 64 single fan and one on my 65 dual. Both are capable of systematically turning on fans seqenstionally or when the A/C is activated. One is the PAC-2750 by Dakoda Digital and the other is a Painless Wiring P/N 30114 dual fan controller. These are "no bullsh$t" units and have run-on features to exhaust heat after the engine is shut down, accurate on/off user settings and the Dakota will show the current coolant temp and count down timer for "after run". Obviously 2 relays are required but if only one fan is required at any given time, or none at all, you can see the advantage of better controllers in managing power requirements and heat management. The Painless unit is PWM capable and will up the speed of the fans as required. Isn't technology a wonderful thing? Prices for these controllers is reasonable and shouldn't put a dent in anyone's pocket book and sure beats the hell out of mounting a probe in one of the hoses or tying it on to the rad face. Do it once, do it right.

 

[Derwud]

This is what I would run..

http://www.hotrod.com/how-to/interi...n-controller-can-save-your-electrical-wiring/

 

[1968rick]

I always wonder why people go with electric fans. Had them in the past in a hot rod and it was a pain in the ***. They simply put to much of a load on the electrical system.

 

[747mopar]

Not sure what your refering to with probes? This is what I was talking about.



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I always wonder why people go with electric fans. Had them in the past in a hot rod and it was a pain in the ***. They simply put to much of a load on the electrical system.

I prefer mechanical fans in most applications but electric fans have their place as well. To say they put to much load on the electrical system simply implies that the installer didn't do his homework, a big enough alternator and relays pulling the load from the battery isolates the fans from the rest of the system so it's a matter of doing it right. Another thing to consider is this, when does your car get the hottest??? In stop and go traffic? What's that mechanical fan doing when you need it most...... running at it's slowest speed!

In my case I'm switching my motor over to a more modern single serpentine belt that spins the pump backwards so fan no worky no more. Also with things as tight as they are up front in a 69 Charger the fan and shroud make lifter adjustments a real bare not to mention I prefer to not have blades whipping around while working under the hood.

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Thanks guys... as usual you guys always steer me towards spending more money but I like to do it once. The controllers do sound like the way to go so I'll be looking into them.

 

[67 coronet]

I eliminate the mechanical fan all together and just run a dual electric setup.people talk about too much electrical draw,but as 747mopar said,you should have it set up right in the first place.100 amp alt,twin relays(one for each fan).I just run them on a manual switch.if you have never removed a mechanical fan,you will be amazed at the power diff and ability for the eng to spool up faster.

 

[747mopar]

I eliminate the mechanical fan all together and just run a dual electric setup.people talk about too much electrical draw,but as 747mopar said,you should have it set up right in the first place.100 amp alt,twin relays(one for each fan).I just run them on a manual switch.if you have never removed a mechanical fan,you will be amazed at the power diff and ability for the eng to spool up faster.

Ooooooooooo..... did you say FER RACIN! Hadn't really thought about the performance side of it but I imagine it will free it up a bit.

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The debate is over, drove up to Summit and looked at the options and bought this one. My first question when narrowing things down is where is it made which this is made in the USA. The other reason was mostly because of how much it cleans up the installation with a simple box, no wires looping from relay to relay and has plenty of options for controlling dual fans.



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This was on display as you walked in, exactly how I was going to wire it. Thought I'd post it for those wanting a cheaper route. This route would be about $9 for a double relay, roughly $25 for a thermo switch, $7 for a breaker, some wire and terminals ends (the trinary should be with your A/C stuff). Notice the trinary is simply grounded on one side then fastened down to the thermo switch meaning either one creates a ground and the fans are on.
Hope this helps.

 

[Dennis H]

When your car was made, Ma Mopar came up with amazing and effective cooling design. Copper, thermal fan, shroud. All these years later the 440 in my wreck runs cool. Under all circumstances. High temps, altitude etc.

 

[65 3 times]

Great thread,lots of good information. I love the new tech Derale controller. I have learned that on the street above 25 mph no fan needed. A/C or none same result. In traffic or stage lane it's a big deal. Prior talk about wiring to the load is utmost important. I have had good results with manual switch and relay but it's one more thing to remember. Great Thread THANKS. Dave

 

[747mopar]

When your car was made, Ma Mopar came up with amazing and effective cooling design. Copper, thermal fan, shroud. All these years later the 440 in my wreck runs cool. Under all circumstances. High temps, altitude etc.

Well that amazing design takes up room that I don't have, requires proper water pump rotation which I will no longer have because I'm going to the superior serpentine setup (how many new cars run v belts?), allows temperatures to rise in stop and go traffic (does your new car with electric fans do that?) and robs horsepower. Say what you will but you can't argue that serpentine belts run forever without a hiccup and cars with electric fans stay just as cool in stop and go traffic.

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Great thread,lots of good information. I love the new tech Derale controller. I have learned that on the street above 25 mph no fan needed. A/C or none same result. In traffic or stage lane it's a big deal. Prior talk about wiring to the load is utmost important. I have had good results with manual switch and relay but it's one more thing to remember. Great Thread THANKS. Dave

Thanks, I try to share my learning experiences for those that might be pondering the same path. Hope it all works out, can't see how 2,700 cfm won't?

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Since I've mentioned that I'm going to a serpentine setup a few times here's the setup. Basically it uses the pulleys and accessories off of a modern magnum motor and neatly positions the A/C pump and alt for a cleaner look.

 

[Derwud]

Who makes that?

 

[747mopar]

Didn't get much done on the wiring but found a home for it and made a bracket for it. This is all hidden under a panel out of sight, I tipped it up to make adjusting the on off temp range easier. Wiring is simple, the 2 red wires out of the bottom are the positive fan feeds, the first fan turns on at the set temp and the 2nd fan turns on once it goes 15 degrees above the setting. The big red wire out of the top hooks to the breaker which wired to the battery, the pair of small black wires are the probe, the yellow is wired to a 12V ign source and the green can be used as a manual on switch or tied into the A/C compressor lead to run the fans while the A/C is on. Pretty easy



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Who makes that?

Look in the protouring section under the serpentine belt thread. I started a thread looking for options, theirs a good bit of info there plus the maker actually took the time to chime in and answer questions.

 

[Sixpactogo]

Looks good Devin. If mine does not perform the way i'm hoping, I will be buying one of those Derale units too.

 

[747mopar]

Looks good Devin. If mine does not perform the way i'm hoping, I will be buying one of those Derale units too.

I think it's overkill but it will reduce the load on the alt and cleans up the installation, you'll be fine I'm sure.