Connect 6.0A fan to DC Fan 3A Temperature Control Governor (not enough AMPs?)

[YouCanDoIt]

Hello to all,
I want to buy this DC Fan Temperature Control Governor:



The devices I want to connect:

• Seaflow DC12V inline blower (model SFIB1-270-02)
  Specs (from multiple sources):
    Max Draw (A): 6.0A (source)
    Working current: 3.77A (source)
    Max amperage capacity: 2.5A (source)
  
• Mini DC12V water pump
  Specs:
    Power consumption: 4.8W.
    Rated voltage: 12V DC.
    Max rated current: 400mA (source):

I'm not sure on how to interpret the above data, but I feel that the PCB controller is not able to provide the amperes required by the devices (at least not for the fan). Is this correct?

So, the question is pretty simple: is there a workaround? May be I could modify the board with more suitable components?

Unfortunately I have not been able to find alternative boards more suitable for my setup (I need fan speed regulation based on detected temperature while most of such boards just power off the fan). This was the closest I could find, but if you know alternatives, please let me know!

Many thanks to all!

[SmallCog]

Use the board to trigger a relay

Use the relay to switch the fan

Oversize the relay, don't get a 6A relay to switch a 6A fan, use like a 20A relay.

[themadhippy]

Use the board to trigger a relay

Use the relay to switch the fan

rather defeats having  a variable speed fan controller

[SmallCog]

My apologies it looked like a simple on/off thermostat at first glance

[ledtester]

How about get the SFIB2-270-02 version of the fan which runs at 24V, max draw 3A?
Then use a 12 to 24V DC-DC converter to get the 24V.

I would first make sure the fan is compatible with the "linear voltage regulation technology" used by the controller.

[YouCanDoIt]

Guys, many thanks for your help.

Let me explain better...

This is a portable air conditioner using and as the basic design (the second link should be the same design of the first link with some additional enhancements).

Use the board to trigger a relay

Use the relay to switch the fan

rather defeats having  a variable speed fan controller

Yes, themadhippy is right. My goal is to auto regulate the fan speed based on temperature detected from the attached probe. The higher the temperature, the faster the fan speed, while the lower the temperature, the slower the fan speed.
When desired temperature is reached, then the fan will continue to run at minimum speed ("conservation mode").
This is what does the governor and the regular air conditioners.
Benefits are extended fan life, lower power consumption, lower noise.
Same for the water pump. It is not mandatory, but I thought that reducing power supply while in "conservation mode" is a good thing (and even with no control, it is still convenient to connect it directly to the board rather than using other external connections).

Main problem is that most of the similar controllers I found are designed to work with PWM signals which are only available in 3-4 wire fans. My fan is 2 wires (red and black) and therefore I need a controller like this which basically achieve the same result by increasing-decreasing power supply programmatically.

There are voltage to PWM converters like this, but I feel I'm going to add unneeded complexity and increase chances of issues. Even with this workaround, I think I sill have to go through current limitation. For example on this PWN controller is stated the following:

Working current: <0.1A
Fan current: <5A (on-board connector can withstand, if you need to control higher power, just walk the power cord separately)

What they mean for "if you need to control higher power, just walk the power cord separately". it seems an easy workaround that I could apply even to the board I want to buy.

How about get the SFIB2-270-02 version of the fan which runs at 24V, max draw 3A?
Then use a 12 to 24V DC-DC converter to get the 24V.

I would first make sure the fan is compatible with the "linear voltage regulation technology" used by the controller.

Unfortunately too late. I already have the 12V fan in my hands. I spent hours trying to figure out if was better 12V or 24V and I saw that integration with other devices would have become more complex with 24V. In addition to that, all the DIY projects I saw on youtube only use 12V. So, I preferred to stay on the safe side.

Oversize the relay, don't get a 6A relay to switch a 6A fan, use like a 20A relay.

The fans connect to port 4, I suppose there is no current limitation here. I suspect port 3 is to connect fans in "power off mode" (no speed regulation):


From google I read this:
How can I increase amperage without increasing voltage?
If the electrical circuit contains IC chips called resistors, resistance can also be lowered by using a lower rated resistor, for example, changing a 4 ohm resistor to a 2 ohm resistor. In a circuit, cutting the resistance by half and leaving the voltage unchanged will double the amperage across the circuit.

This seems to be a very risky operation. Board is designed for 3A and who know how many bad things could happen with such modification.

Any idea, guys?
I really need to complete my air conditioner project as soon as possible: from the place I'm writing this thread, temperature reached 35 C° and is worse than hell !

Thanks

[bob8819]

 You need to use pwm to control the MOSFET

[YouCanDoIt]

You need to use pwm to control the MOSFET

I don't understand exactly what you mean. You're talking about PWM versions of the temperature control governors, right? Those types only work with 4 wire fans while mine is 2 wire. The main problem here is amperage of the boards, whether the fans are PWM or DC controlled.

[YouCanDoIt]

It seems like no one is able to help and I suppose it's just because it's not possible if the controller is designed to output less current than the one required by the fan.

So, I will try to see if I can achieve the same result through a different strategy. I found a similar controller with 12A output (which I suppose should be more than enough), but now the problem is different: it is designed to work with 4 wire fans (while mine is 2 wire). I opened a new topic to see if it is possible to use some sort of adapter and make it work even with 2 wire fans.
Thanks

[YouCanDoIt]

For anyone in the same situation, I post here the solution I found.
This controller seems to be able to drive 12A current which should be more than enough to connect the fan, the water pump and a future third device. It also comes with a convenient case.


There is no led, setting it up is much harder and is much less customizable, but still better when the alternative is nothing!
I would have preferred to use the one in this thread because, with the same price, it allows to do much more things and comes with many more features. Unfortunately no one seems to know how to make it work with 2 wire fans. I posted several cheap adaptors that could work, but no one seems to know what could be the right one.

So, for anyone that is trying to do same, the above is the only one solution that should work without any issues, but with lot of limitations.