Fan Wiring

Flyingwills

New member
Joined
Apr 12, 2019
Messages
5
Hi All,

Just needed some advice on wiring of fans to cool the new Eddi i installed a week or two back.

Using a 4W, 12V solar Panel -jaycar.com.au/4-watt-12-volt-solar-panels-amorphous/p/ZM9026

Noctua NF B9 REDUX 92mm - noctua.at/en/nf-b9-redux-1600-pwm

Noctua NF R8 REDUX 80mm - noctua.at/en/nf-r8-redux-1800-pwm

My question is what is the best way to wire these fans to the solar panel?

I currently have them both tapping into the solar panel at the same spot (In parallel). If i power them on at the same time both fans spin. However if i let the sun slowly power them up e.g. from sunrise, Only the 80mm fan spins untill i cover the solar panel entirely, let the fans spin down and then power them up.

Should i wire them properly in parallel?or series?

If parallel which fan in the parallel chain first? (does it matter?)
 
So that solar panel has spec for voltage which are too high for the fans without a regulator.
The panels max power point (best volts/current to operate at) is 17.5V & 286mA (in perfect conditions when the panel is cold)
When the panel heats up in the sun after maybe 1/2 an hour it'll be a lot less output, maybe 70% of the above.

The fans are motorized devices that draw higher current to get them started & effectively "short out" the panel when the sun comes up gradually.
So the trick is to use a device/circuit called a maximizer that lets the panel get to about say 17V & gives the fans whatever current is available.
This will let the fans start much better.
Google this"solar maximizer circuit"
Eg here: https://www.ledsales.com.au/pdf/Maxi_maximiser_instructions.pdf

But you also need 12V regulator in there because the fans are only rated 12V & 17V will blow them eventually.
A simple 12V regulator can be built with a transistor on a heatsink & a 12V zener & a resistor or two.
Eg here: http://www.learnabout-electronics.org/PSU/psu22.php
 
Redpacket said:

So are you saying in the morning when the sun is slowly coming up that it is affecting the fans?

I tried putting two fans of the exact same spec and they both wouldn't start as the sun slowly rose, however when i just turn them off/on they all started spinning.
Is there any way to fix this?

I just need a way to cause the circuit to reset which will triger them to both turn on.
 
Are you OK with simple electronics & soldering or prefer a modlue, eg ebay, jaycar, etc?
 
Redpacket said:
Are you OK with simple electronics & soldering or prefer a modlue, eg ebay, jaycar, etc?

Would prefer to just buy something.
Pretty much if I have two different size fans, the smaller second one spins with sunrise. If you reset, then both work.

If I have two fans same size, then both don't spin with sunrise unless you reconnect them.

Also appreciate all the help
 
You need bigger solar panel or smaller fans or a controller that start Them when enough Sun exist.
 
One thing - can you measure the voltage when 1 fan is spinning and the second attached ?
 
daromer said:
You need bigger solar panel or smaller fans or a controller that start Them when enough Sun exist.

Tried that, I think it's something to do with the fans' control logic board that stops them after a while of having low voltage.

Any recommendations on a controller that would do that?


Cherry67 said:
One thing - can you measure the voltage when 1 fan is spinning and the second attached ?

Wish i could, don't own a voltmeter unfortunately...

But even when the sun is high and the panel is getting maximum solar, the same phenomenon happens. Either only one fan spins or both aren't spinning untill i disconnect and reconnect power.
 
After the inspiring comments of the others, i just assume the current of both fans to start required is more than the panel can deliver. There is a buck converter available which has an MPPT ( wich is an undervoltage shutof) in the Chinese market, i will add the link later. Perhaps this could work.
 
You probably want something that can also maintain a constant current. Your issue is that your fan can probably run at a lower voltage, but it doesn't have enough current to run at 12V. I had this issue on a a pump that requires 12V and 5 Amps.

So for example if your fan is 1A, and your panel is outputting 12V 0.8A (12V*.8A=10W) so it's not enough to start the fans. But your fan is probably fine running at lower speeds if the voltage dropped to 10V and thus increasing the current to 1A (10V*1A=10W).

This is a CC/CV that might work. https://www.ebay.com.au/itm/DC-DC-A...5V-30V-to-0-5-30V-12V-Power-P8J3/283068200555
 
Flyingwills said:
Cherry67 said:
After the inspiring comments of the others, i just assume the current of both fans to start required is more than the panel can deliver. There is a buck converter available which has an MPPT ( wich is an undervoltage shutof) in the Chinese market, i will add the link later. Perhaps this could work.

Would this one do the trick?

https://www.ebay.com.au/itm/1425200...04&_trkparms=gh1g=I142520044960.N41.S1.R1.TR2

no. I mean

https://www.ebay.com/itm/MPPT-Solar...C-CV-buck-Charging-Module-12V-5V/172711371638

or

https://www.ebay.com/itm/5A-MPPT-So...erter-LED-CC-CV-Battery-Charging/322672893123

its the same module, one is with display of current and voltage on in- and output. Would be fine for you because you have no Multimeter.
btw you should buy a multimeter, at least a cheap one. You can hardly do anything without.
 
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