Dual fan controls

[84cutspreme]

Well fixed the issue for now. Have one fan on the sender and one on a switch so idling at a light I can switch the one on and engine stays pretty cool. Also found that painless now makes a nice controller, high and low speed with adjustable temp setting...unfortunately its pricey. #30140. Looks pretty nice and does everything I would like it, only thing I won't be able to use is optional vss input to set fans off at adjustable highway speeds

 

[darbysan]

Just posted this in another thread, but thought it might apply here.

Here is the three-relay setup I use. Basically, if you run both fans in series, each fan will be running at 1/2 speed (low) (Relay 1 triggered via a ground signal). To go to high, relays 2 and 3 both get triggered. This breaks the serial connection of the motors, and supplies power to both fans ( high speed). I'm lucky enough to be able to use the ECM to control some of the temps, but you can easily do this without an ECM. Your engine temp switch can trigger the low speed circuit, and your AC or manual switch can trigger the high speed.

http://ls1tech.com/forums/conversions-h ... agram.html

 

[jociha]

Just posted this in another thread, but thought it might apply here.

Here is the three-relay setup I use. Basically, if you run both fans in series, each fan will be running at 1/2 speed (low) (Relay 1 triggered via a ground signal). To go to high, relays 2 and 3 both get triggered. This breaks the serial connection of the motors, and supplies power to both fans ( high speed). I'm lucky enough to be able to use the ECM to control some of the temps, but you can easily do this without an ECM. Your engine temp switch can trigger the low speed circuit, and your AC or manual switch can trigger the high speed.

http://ls1tech.com/forums/conversions-h ... agram.html

Are the fans designed to run at 6 volts? That is what you are doing. Remember half the volts equals double the amps and if not designed for this application the fans will over heat and burn out. Why not just run one fan [the one in front of your trans cooler if you have one] for low and two fans for high that is in CFM [air flow] terms what you are doing anyway.

 

[darbysan]

Just posted this in another thread, but thought it might apply here.

Here is the three-relay setup I use. Basically, if you run both fans in series, each fan will be running at 1/2 speed (low) (Relay 1 triggered via a ground signal). To go to high, relays 2 and 3 both get triggered. This breaks the serial connection of the motors, and supplies power to both fans ( high speed). I'm lucky enough to be able to use the ECM to control some of the temps, but you can easily do this without an ECM. Your engine temp switch can trigger the low speed circuit, and your AC or manual switch can trigger the high speed.

http://ls1tech.com/forums/conversions-h ... agram.html

Are the fans designed to run at 6 volts? That is what you are doing. Remember half the volts equals double the amps and if not designed for this application the fans will over heat and burn out. Why not just run one fan [the one in front of your trans cooler if you have one] for low and two fans for high that is in CFM [air flow] terms what you are doing anyway.

You may have a point about the amps, just don't know. This is the way GM designed them, and wired from the factory. Actually got the relay pack from a Cadillac pre-wired.

 

[jociha]

Just posted this in another thread, but thought it might apply here.

Here is the three-relay setup I use. Basically, if you run both fans in series, each fan will be running at 1/2 speed (low) (Relay 1 triggered via a ground signal). To go to high, relays 2 and 3 both get triggered. This breaks the serial connection of the motors, and supplies power to both fans ( high speed). I'm lucky enough to be able to use the ECM to control some of the temps, but you can easily do this without an ECM. Your engine temp switch can trigger the low speed circuit, and your AC or manual switch can trigger the high speed.

http://ls1tech.com/forums/conversions-h ... agram.html

Are the fans designed to run at 6 volts? That is what you are doing. Remember half the volts equals double the amps and if not designed for this application the fans will over heat and burn out. Why not just run one fan [the one in front of your trans cooler if you have one] for low and two fans for high that is in CFM [air flow] terms what you are doing anyway.

You may have a point about the amps, just don't know. This is the way GM designed them, and wired from the factory. Actually got the relay pack from a Cadillac pre-wired.

If this is a factory design then you should be ok, motors run in this fashion require better windings and better insulation.

 

[gp02a0083]

The relay control is a good basic way to start out, and yes amperage of the fans has to be considered to a point. You guys gave me a great idea for a programmable fan control project, really simple to do with the arduino micro-controller development kit i have. A high/low fan speed can be easily achieved, having a varying speed fan controller would require some pulse width modulation. So the big question for you guys is is the varying fan speed something in high demand or a simple high/low speed? I have a few other ideas that could be done.

 

[jociha]

The relay control is a good basic way to start out, and yes amperage of the fans has to be considered to a point. You guys gave me a great idea for a programmable fan control project, really simple to do with the arduino micro-controller development kit i have. A high/low fan speed can be easily achieved, having a varying speed fan controller would require some pulse width modulation. So the big question for you guys is is the varying fan speed something in high demand or a simple high/low speed? I have a few other ideas that could be done.

Variable speed fans running according to water temp would be great, but I do not know of a 12v fan that could handle less than 50% run speed. It would take a purpose built fan to work without overheating. You will notice the couple so called variable speed controllers on the market that they all have a 50% min. start speed.

 

[gp02a0083]

The relay control is a good basic way to start out, and yes amperage of the fans has to be considered to a point. You guys gave me a great idea for a programmable fan control project, really simple to do with the arduino micro-controller development kit i have. A high/low fan speed can be easily achieved, having a varying speed fan controller would require some pulse width modulation. So the big question for you guys is is the varying fan speed something in high demand or a simple high/low speed? I have a few other ideas that could be done.

Variable speed fans running according to water temp would be great, but I do not know of a 12v fan that could handle less than 50% run speed. It would take a purpose built fan to work without overheating. You will notice the couple so called variable speed controllers on the market that they all have a 50% min. start speed.

the Idea I have is to use one or two sensors up on the radiator like most typical stock setups I've seen are. the additional sensor would be on the engine, to monitor the temperature on the block side. my idea behind this is to keep the temperature as stable as possible and using the additional sensor would in a way turn on the fans prematurely to keep the temperature fluctuations down, rather than just turn on and off at a specific temp to keep the temperature in a broad range. i'm curious to the speed controllers you found, and if they are running PWM and MOSFETs to control the fans or just using some relays and power transistors. I've so far tried stuff like PWM on my 1/24 scale slot cars, and I get much more control overall in addition to very slow speed control and they run on 12V-13.8V DC. PWM will allow the fan motors to run cooler depending on the duty cycle used. It would be up to the specs of the fan on how low of a speed i may be able to run them at.
This was just an Idea, I do like the more analog approach using relays being its simple and works, however if you can use a micro controller that opens up a bunch of options.

 

[pontiacgp]

if you do put a sensor in the rad put it on the side where the top rad hose is. That will indicate the heat of the coolant coming from the engine

 

[jociha]

Here is mine, it works great here, keeps engine at 180deg.
The VFD conntroller I saw was by flex a lite, I think.
You are correct about the spec's of the fan, I don't think any of them like running below 50% for fear of overheating the windings.