# renegade fan replacement



## davetcan (Feb 27, 2006)

Guys,
the fan in my Egnater Renegade is getting a bit noisy, always has been really. Looks like a bog standard computer fan. The one in it says 12V, 2.0W brushless DC. It has just a 2 wire connector on it, red and black wires. I have a ball bearing fan from an old desktop kicking around that I'd like to try. It says 12V 0.22A with a 3 wire black, red, yellow connector. Would I be safe to give it a go? Assume I would just solder the 2 wire connector onto the black and red wires of the old fan?

I'm not remotely electrically knowledgeable 

This guy has done something similar.

http://chasingthetone.blogspot.ca/2013/03/egnater-replacment-fan-mod.html


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## davetcan (Feb 27, 2006)

Where the heck is "Mike" Hammer when I need him?


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## dodgechargerfan (Mar 22, 2006)

12V 0.22A calculates to about 2.75W. So, you're going to be drawing a bit more power than the fan that's in there.

You'd need to know that the circuit providing that power could handle delivering that additional power.
And you would heat that circuit up more than the current fan. Would you notice the extra heat? No idea. It depends on the components.

Edit: for reference, 12V at 2W calculates to 0.166666667A. So, it's not a LOT of additional current, but you still need to know the circuit components can handle it.


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## davetcan (Feb 27, 2006)

So ideally I really need a fan that draws less current to be safe? Or I'll just stick the old one back in, LOL.


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## greco (Jul 15, 2007)

davetcan said:


> Where the heck is "Mike" Hammer when I need him?


I'm sure you mean "Mark" Hammer!

If there is a concern about current draw and heat (which I doubt), could the addition of a small resistor in the fan circuit prevent that?

I am almost sure that Wild Bill indicated that these fans will operate at a slightly lower voltage but will just have slightly slower fan speed and, as a result, slightly less air movement. 

Cheers

Dave

After reading this...I hope I am "slightly" correct...LOL


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## dodgechargerfan (Mar 22, 2006)

davetcan said:


> So ideally I really need a fan that draws less current to be safe? Or I'll just stick the old one back in, LOL.


To be absolutely sure and without having to figure out the specs of the circuit components, yes. The same or lower current draw is only way to 100% safe.

Keep in mind too, that a lower current will equal lower Wattage and while that sounds like a good idea for power efficiency, the fan will likely turn slower. Unless it's a more efficient design.

I've pulled computer fans apart and greased the bearings with great success. That might be worth a try if you feel that the fan is otherwise not useable.


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## dodgechargerfan (Mar 22, 2006)

greco said:


> If there is a concern about current draw and heat (which I doubt), could the addition of a small resistor in the fan circuit prevent that?


That would work.
I don't think I have enough coffee in me yet to calculate that.


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## dodgechargerfan (Mar 22, 2006)

dodgechargerfan said:


> That would work.
> I don't think I have enough coffee in me yet to calculate that.


Okay. I couldn't NOT think about it once it got in my head.

The exact resistance needed to limit the current draw back down to 0.1666667 is 226 ohms.
A 200 ohm resistor ought to get you close enough for comfort.

12V = 0.053A x R
R = 12V / 0.053A
R = 226 Ohms.


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## davetcan (Feb 27, 2006)

Inside joke 

Thanks for the responses guys. I'll see if I can pick one up locally.



greco said:


> I'm sure you mean "Mark" Hammer!


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## greco (Jul 15, 2007)

..................


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## epis (Feb 25, 2012)

C'mon guys, that current draw difference is insignificant, probably even less than calculated. (measure voltage, I'm guessing it runs on lower than 12V, Most likely they used heater 6.3V rectified for fan) Cheers, Damir


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## jb welder (Sep 14, 2010)

dodgechargerfan said:


> The exact resistance needed to limit the current draw back down to 0.1666667 is 226 ohms.
> A 200 ohm resistor ought to get you close enough for comfort.
> 
> 12V = 0.053A x R
> ...


You don't really want to drop the entire 12V across that resistor, do you? :smile-new:


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## dodgechargerfan (Mar 22, 2006)

jb welder said:


> You don't really want to drop the entire 12V across that resistor, do you? :smile-new:


It would be in series with the circuit feeding the fan. I'd have to assume that there is 12V coming in and we need to limit the current.
So, yeah. No?

Granted , we are going to need something like a 3W resistor. All the more reason to find out what's feeding the fan now...


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## dodgechargerfan (Mar 22, 2006)

epis said:


> C'mon guys, that current draw difference is insignificant, probably even less than calculated. (measure voltage, I'm guessing it runs on lower than 12V, Most likely they used heater 6.3V rectified for fan) Cheers, Damir


Agreed about measuring it. 
And knowing what the circuit is actually feeding it is really the only way to be certain.

My calculations are based on the info given.


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## epis (Feb 25, 2012)

Do not use resistor, it's not gonna help power usage, what's happening, part of power consumption instead of fan will be wasted in resistor producing heat.


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## jb welder (Sep 14, 2010)

dodgechargerfan said:


> It would be in series with the circuit feeding the fan. I'd have to assume that there is 12V coming in and we need to limit the current.


Yes, a series circuit, but only a fraction of the voltage should be on the resistor, the bulk of it should go to the fan. Your calculation put the entire 12V across the fan, so with very little current, all the voltage would be dropped across the resistor with none for the fan.
Ideally, you would want to know the resistance of the fan, or actually measure the current. I think the resistor value needed for a series circuit would be very low, maybe fraction of an ohm.
But that's all academic, as Epis mentioned, power diverted to the resistor is wasted. If the goal is to reduce the series current to what it would have been with the old fan, then you will end up reducing the speed of the new fan.

The current difference between the 2 fans should be close enough. You want to make sure you have at least as much CFM venting with the new fan, and mostly it needs to be quieter!


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## davetcan (Feb 27, 2006)

All done. Found a nice quiet fan with exactly the same current draw. Not sure about CFM but it feels pretty good and is nice and quiet. Had trouble finding the right connectors so I just hardwired the damn thing in, it's not like i need to move it around at all. I have it blowing air onto the tubes as opposed to drawing warm air away from them. Not sure if it matters but the way it's located and angled there's not much place for the hot air to go. of course i didn't think to check it when I took it out, LOL. I also took the advice of the guy on the page I linked earlier and offsite the valance a bit to provide an air gap.


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## greco (Jul 15, 2007)

Well done...Congrats!!

Cheers

Dave


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