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Electrical Guys - Radiator Fan Controller Wiring: Backfeed possible?

freerider15

NAXJA Forum User
Location
FoCo, Crawlorado
Ok, so I'm getting the wiring finished up on the buggy (finally).

I've got a DCControl's fan controller for my Taurus fan.

As it's described:

Our constant temperature, full variable speed controllers have long been considered the best on the market. They can be utilized with virtually any cooling fan and employ pulse width modulation in order to set the fan to any speed in order to attain a constant temperature without cycling, regardless of driving conditions.

Now...what I'm planning:

I could just hook it right up (i.e. high speed wire to fan controller output) as some do (how installation instructions go).

I however, would like to be able to turn the fan off, or bypass the controller as safeguards.

I've got two rocker switches (Contura V's) that I'm planning on using.

One would be on full time, and just let the fan controller do it's thing. It I flipped it to off, there would be nothing going to the fan and thus off.

I would have another switch, for full on. When this switch is hit, it would be a straight from power pull, 100% on fan.

In order to do this, I would need to feed both power source wires into the one feed wire for the fan...(2 into 1).

What I'm worried about, is any back feed towards the controller if I put the fan on 100%. I know the flow of electricity will always want to take the path easiest traveled, but I want to make sure I wouldn't harm my nice expensive controller :laugh:

So, thoughts, experience...?
 
Some of the later ECU would trigger the CEL if they detected ground on the control circuit. The way around that is a diode on the ground wire so that the ECU does not detect the unexpected circuit.

In my case, the ECU is not part of this at all.

Everything is stand alone in the buggy. The normal ECU controlled temp on/off is not connected anywhere in this circuitry (Its actually cut, taped, and bundled since I didn't feel like pulling it from the fuse panel).
 
The Taurus fan pulls a lot of amperage, much more than what the switches were designed for.
I would use a 70-amp relay(s) to power the fan, they are not expensive and will save the rocker switches from an early death.
http://www.waytekwire.com/item/7536...jDB5x50IgHSjP58mk9rsbPnbrXStu_yb9vxoCu8Xw_wcB
A minimum of 10-gauge wire, from the battery, to the relay and then to the fan, is recommended. Same for the ground wire.
Make sure to fuse the circuit too.
Relays can also be used to isolate circuits, preventing feedback problems. Diodes are also be very useful for isolation.
 
The Taurus fan pulls a lot of amperage, much more than what the switches were designed for.
I would use a 70-amp relay(s) to power the fan, they are not expensive and will save the rocker switches from an early death.
http://www.waytekwire.com/item/7536...jDB5x50IgHSjP58mk9rsbPnbrXStu_yb9vxoCu8Xw_wcB
A minimum of 10-gauge wire, from the battery, to the relay and then to the fan, is recommended. Same for the ground wire.
Make sure to fuse the circuit too.
Relays can also be used to isolate circuits, preventing feedback problems. Diodes are also be very useful for isolation.

Two steps ahead of you.

I've already got a bag full of 70/80A Relays laying around, and 10 gauge wire :D
 
Two steps ahead of you.
I've already got a bag full of 70/80A Relays laying around, and 10 gauge wire :D

Guess if I had looked at your signature, I would have known that.
You would be surprised at some of the electrical installations I see.
 
Does the controller have an a/c input to turn fans on full tilt when a/c requested? just wire a switched B+ to that
 
I say you're over thinking it. Let the controller control the fan and on the unlikely chance it fails just bypass it then.
 
Does the controller have an a/c input to turn fans on full tilt when a/c requested? just wire a switched B+ to that

It does have an A/C input, but it's not a full on.

I say you're over thinking it. Let the controller control the fan and on the unlikely chance it fails just bypass it then.

If this we're a "normal" rig that would be one thing.

But with wheeling what I do, having as much control as possible is key. I'd rather not have to pull the dash panels in the case that the fan controller fails. As well, this provides me with the option to turn the fan off, in case stuff might come in contact with the fan blades (my fan/radiator are laid at an angle in the rear of the buggy).

With the DPDT switch, wiring will be simple with just one relay added for full on.
 
You need to place a phone call to dcc and they can clear up your questions with pin point accuracy and not us internet warriors. =) IMO your overdoing it with a dcc controller if your looking for trail simplicity. You should have used a temp switch in radiator and ran a HUGE relay to operate the fan. It can be done with diodes (LARGE Diodes) to protect the fan controller. But I digress call DCC
GL bud
 
You need to place a phone call to dcc and they can clear up your questions with pin point accuracy and not us internet warriors. =) IMO your overdoing it with a dcc controller if your looking for trail simplicity. You should have used a temp switch in radiator and ran a HUGE relay to operate the fan. It can be done with diodes (LARGE Diodes) to protect the fan controller. But I digress call DCC
GL bud

Apples and oranges.

I like my stuff to work, and work properly.

Using a temp switch while easy, does nothing like this.

Why risk having startup on a fan pulling that many amps, and keeping a two speed fan on needlessly.

Believe me, at first I thought like you did, then I realized that might be a good idea...for a supporting electric fan.

As I said before, it's one thing when you're on a "normal" trail. But when you're on a trail that an extraction could take more than a day due with a shot/overheated motor...you make damn well sure everything is as fail proof as possible :laugh: "Trail simplicity" can also very well lead to "Trail Plug".

I've learned from other's mistakes. :D

I did call DCC, but didn't get through.
 
Apples and oranges.

I like my stuff to work, and work properly.

Using a temp switch while easy, does nothing like this.

Why risk having startup on a fan pulling that many amps, and keeping a two speed fan on needlessly.

Believe me, at first I thought like you did, then I realized that might be a good idea...for a supporting electric fan.

As I said before, it's one thing when you're on a "normal" trail. But when you're on a trail that an extraction could take more than a day due with a shot/overheated motor...you make damn well sure everything is as fail proof as possible :laugh: "Trail simplicity" can also very well lead to "Trail Plug".

I've learned from other's mistakes. :D

I did call DCC, but didn't get through.

Emmmm you say K.I.S.S. and then turn 180 and go complicated.
Ok I guess I can draw it out for ya. Take 2 70 amp relays. wire one relay like 30 to fan batt high. run 87 to a fuse then to battery. take 85 and run it to key power (now it CAN NOT turn on without key on) run 86 to temp switch in radiator and other side of temp switch to gnd. It just cant get any more simple. do the same with low side and a lower temp switch.
now run a wire from 86 on relay to a switch in your panel then other side to gnd
Or get yourself a Diode that can take amx amp draw from the Taurus fan and run it into the high side of the fan and other side goes to HIGH amp relay 30, 87 to batt w BIG fuse, 86 to key power or gnd. whatever way u want it to be keyed or not keyed. and 85 to gnd or power depending how you used 86
I know nuthing :laugh2:
ASE Certified Master tech 29 years at this crap and electrical is my specialty :eyes: :edit: Wait it can get more simple use a manual fan =)
 
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Apples and oranges.

I like my stuff to work, and work properly.

Using a temp switch while easy, does nothing like this.

Why risk having startup on a fan pulling that many amps, and keeping a two speed fan on needlessly.

Believe me, at first I thought like you did, then I realized that might be a good idea...for a supporting electric fan.

As I said before, it's one thing when you're on a "normal" trail. But when you're on a trail that an extraction could take more than a day due with a shot/overheated motor...you make damn well sure everything is as fail proof as possible :laugh: "Trail simplicity" can also very well lead to "Trail Plug".

I've learned from other's mistakes. :D

I did call DCC, but didn't get through.

I'm local, I could come over and see what you are up to and help you get that all sorted out. If you didn't know, I'm and Electrical Engineer. I probably have what you need in my parts box.

Tom
970-391-8927
 
Emmmm you say K.I.S.S. and then turn 180 and go complicated.
Ok I guess I can draw it out for ya. Take 2 70 amp relays. wire one relay like 30 to fan batt high. run 87 to a fuse then to battery. take 85 and run it to key power (now it CAN NOT turn on without key on) run 86 to temp switch in radiator and other side of temp switch to gnd. It just cant get any more simple. do the same with low side and a lower temp switch.
now run a wire from 86 on relay to a switch in your panel then other side to gnd
Or get yourself a Diode that can take amx amp draw from the Taurus fan and run it into the high side of the fan and other side goes to HIGH amp relay 30, 87 to batt w BIG fuse, 86 to key power or gnd. whatever way u want it to be keyed or not keyed. and 85 to gnd or power depending how you used 86
I know nuthing :laugh2:
ASE Certified Master tech 29 years at this crap and electrical is my specialty :eyes: :edit: Wait it can get more simple use a manual fan =)

I'm an M.E., so I do know a few things about it myself :D

What you described was pretty much actually my original plan. However, after reading about guys having issues with the fan/cooling with that setup...I decided to go the route many of them did: DCControls controller. Since it is a 0-100% controller, I don't get the electrical amperage surge that you do otherwise. There are other controllers out there (though none that do remotely what this one does), but I've not heard the greatest things about them. As well, what do you hook up the temp controller to...the high or low speed? Low speed...hope you don't start to get too hot. High speed...it has cooled my temp from 220 to 180 in two minutes flat...so that would be a lot of on/off/on...

The other thing with this setup now, is that I shouldn't have to hear the fan - on...off...on...off...on...etc. Since this setup only has the fan on enough to keep what temp you set it to, it only pulls that much from the fan (i.e. if you only need 23% on, that's what it will pull).

Since my radiator/fan is mounted in the rear, in the "open", I hear it...very well. It will be a nice change for there to be a slow ramp up, with it very rarely if ever needing 100%.

If this we're in a normal full bodied XJ, different story.

I'm local, I could come over and see what you are up to and help you get that all sorted out. If you didn't know, I'm and Electrical Engineer. I probably have what you need in my parts box.

Tom
970-391-8927

Tom, you and Ken were the two I was hoping would pipe up.I definitely so remember EE is one of the several degrees you have :laugh:

I think I've got it handled at this point, but I'll definitely give you a call if I have any questions, and to setup a M&G sometime :D
 
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