Using V1/V2 V3/V4 for DC fan control?

micaheli

micaheli

New member
Since I'll be using the AWM for my lights, I don't need to use the V1-V4 ports for lighting and I'd really hate to see those ports go to waste. :)

So, since they output 4V-10V variable voltage, I should be able to combine what I learn from THIS page with what I know from THIS page and get a variable speed DC fan, yes?

I realize that I'll never be able to push the fan at it's full 12V potential, but will still move enough air if I get a big enough fan.

Thoughts?

--Micah
 
No the VSP only outputs miliamps dc voltage (signaling voltage) and will not handle a load such as a fan. Not sure but if you try you may wind up causing all type of issues including catastrophic failure of your entire system.

Mark
 
If there's one thing I'm trying to avoid, it's catastrophic failure of my entire system. :)

I suppose I'll have to find a DC to PWM output circuit for this.... A powered one.... I bet some of those PC fan controllers have this capability.

Thanks for the input Mark!
 
Maybe THIS would work if I unsoldered the POT and used one of the v1-v4 outputs as the POT input voltage. Then I can create profiles called "FANLOW","FANMED", and "FANHIGH". Seems plausible.. perhaps I'll contact neptune about this....
 
I'm not sure that is an active PWM controller, either. It may just be a large passive pot, in which case it wouldn't work. I think you are looking for something more like this. (If the link doesn't work, just do a search for "0-10v speed control" on eBay.)
 
PWM is optional really. As long as I can control the voltage output variably, I can pick a fan and control it's speed accordingly.
 
True, as long as you don't exceed the Apex's current capability. PWM is the probably the best way to go however.
 
Finding large quiet PWM fans is a tough task though. Most PWM fans are 120mm and under. I'm looking for a LARGE fan.. 200-360mm. :) As long as the driver is powering and controlling the voltage output, it shouldn't matter what the method is as long as the control input can be super weak.
 
In PC jargon, PWM fans are those that have a 4 pin header connector so the fan can be directly controlled by the motherboard. But "non-PWM" fans can still be speed-controlled by PWM supplies like the one I linked, as long as the pulse frequency is in the 30k range. Newegg sells several fans over 200mm that should work.

I looked into this very topic, and wasn't able to find an adjustable linear regulator solution for controlling voltage. It was much easier to create a circuit for voltage-controlled pulse width using 555 timers and a power MOSFET. The unit on eBay does the same thing.
 
I went that route first. Hope you didn't order one, they don't work. The PWM doesn't happen at the proper frequency, the fans make a horrible noise and don't spin very fast. It may be that they don't have the proper amount of output capacitance or back EMF protection. Funny things happen when using pulses to charge motor coils, you get a lot of back EMF from collapsing magnetic fields.

There are lots of different ways to use a 555 timer-based circuit to accomplish what you want, but it is difficult to "tune" unless you have an oscilloscope. Some schematics are here.

In the end, I think you would be best off to use the product I linked first.
 
Weird. Not sure how i missed that link entirely. Yeah, your link is perfect. Glad you tried all of this and have worked out the kinks! Hehe. Did you end up getting everything working and apex happy?
 
I did get a circuit breadboarded and working, and I have no doubt it will work fine if/when I decide to use it on my canopy. Not as much need for extra cooling in the winter here, so it may have to wait a few months. : )
 
I'm going to get one of those controllers that you linked to. I really hope it works out. With PWM, do you think I could control dual fans with a single controller?
 
Yes I think if you hook up any fans in parallel in the way the eBay circuit shows you should be fine.
 
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