[SOLVED] Looking for confirmation: when daisychaining rbg fans...

Viorala

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May 20, 2019
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If you have more than 2 or 3 you have to use the molex power connector, correct? Am I correct in thinking that the rbg port on the motherboard is subject to the same ampere power limits as the sysfan ports?
 
Solution
Subject to amp limits, yes. SAME limit, NO.

See your mobo manual p. 14. I says you have two D_LEDn headers for 3-pin 5 VDC ADDR RGB (Digita; RGB) lighting units. It says these have a limit of 5 A max current load, or 1000 LED's, whichever way you are counting. It does not make it clear whether that is for BOTH headers combined, or for EACH header separately.

You really can NOT connect ARGB lighting units to a Molex connector. What any ARGB Controller does (and that includes the Controller on your mobo that feed these headers) is provide both power AND Control of the light display. Trying to provide power only from a Molex (even if you get it right and don't burn out your lights!) will get you NO lights without digital instruction...

Paperdoc

Polypheme
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Subject to amp limits, yes. SAME limit, NO.

See your mobo manual p. 14. I says you have two D_LEDn headers for 3-pin 5 VDC ADDR RGB (Digita; RGB) lighting units. It says these have a limit of 5 A max current load, or 1000 LED's, whichever way you are counting. It does not make it clear whether that is for BOTH headers combined, or for EACH header separately.

You really can NOT connect ARGB lighting units to a Molex connector. What any ARGB Controller does (and that includes the Controller on your mobo that feed these headers) is provide both power AND Control of the light display. Trying to provide power only from a Molex (even if you get it right and don't burn out your lights!) will get you NO lights without digital instruction packets from the Control Line of the mobo header.
 
Solution

Viorala

Reputable
May 20, 2019
150
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4,615
Hm, good to know, thanks. I take it that the same rules are in play with 12v rbg ports? See c1 led on my mobo. I think I'm going to have to daisy chain rbg fans, not arbg, but I just have to make sure I don't go over 12volts?

I promise I'm not stupid but I am just not retaining this fan voltage information well. This is my third post on it. I'm afraid of blowing up my mobo. When I was case hunting I found two that had reviews saying a small fire started around the fans. Thanks for patience.

Eventually I'll replace with noctuas and arbg fans.
 

Paperdoc

Polypheme
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SIMILAR rules for plain RGB headers. Your mobo has the same kind of info, but the CURRENT limit on the plain RGB headers is not the same, so read that carefully. You do not determine the voltage consumption of these headers - that is fixed by the design (see below). You DO impact the max CURRENT (in Amps) by choosing how many devices to connect to a mobo lighting header.

A little help (I hope). There are two kinds of RGB lighting systems dominating the market now. The Plain RGB system uses a 4-pin connector system that supplies to lights a common 12 VDC power line and three separate Ground lines. The LED's used come in three colours: Red, Green and Blue. Along the light strip the LED's of one colour (say, Red) are all connected to the Red Ground line and all do the same thing at once. Same for the other two colours. The Controller for these on the mobo, via the output header, manipulates the three Ground lines to produce a large range of colours that can change over time. But at any one moment, the entire strip is the same colour. With this system the female (with holes) connector on the end of the lighting unit's cable has a marker for the +12 VDC pin (or hole) on one end of the connector. At every connection point you MUST aligns those markers.

The more complex system is called Addressable RGB or ADDR RGB or ARGB or Digital RGB. It uses a 3-pin connector (looks like the 4-pin one with one pin missing) that supplies common +5 VDC and Ground lines, and a Control Line. Along the strip the LED's are organized into Nodes. Each Node contains one LED of each colour plus a control chip. That chip listens to the Control Line, which carries addressed data packets with instructions for the Node chips. Each Node's Control Chip responds only to packets addressed to it, and manipulates its own three LED's only. So at any one moment, every Node along the strip can be a different colour, and this allows much more complex displays like rainbows. Since the connectors on the cables for these use a (4-1) pin layout, there is no confusion about which way to plug them together.

Because both the supply voltage and the method of control are so different between these two you cannot mix them on the same circuit. To distinguish which is which, read the specs for Voltage, Pins on the connector, and name (RGB or ARGB etc.), Also check the photos - the ARGB systems VERY often feature rainbow displays that a plain RGB system cannot do.

An RGB Fan or ARGB Fan is really two devices in one unit. It has a fan motor, and also a lighting system built into the frame. The unit has two separate cables for these devices. The one for the fan ends in a female standard fan connector with 3 or 4 holes - depends on whether this is an older style 3-pin Voltage Controlled Fan, or a newer type PWM 4-pin fan. That goes to a mobo fan header. The cable for the lights ends in a wider connector with either 3 or 4 holes - depends on whether the lights are the new 3-pin (5 VDC) ARGB system or the simpler 4-pin (12 VDC) plain RGB system. That goes to the correct type of mobo lighting header. Note the big source of confusion in the names. The "3-pin" and "4-pin" names are used both for motors and lights, BUT these two types of devices are NOT related, so the labels means different things for each type.

Mobo makers sell mobos with lighting headers in 4 groups: some with no lighting headers, some with only plain RGB (4-pin 12 VDC) headers, some with only ARGB (3-pin 5 VDC) headers, and some with both types of headers. All of them provide free downloadable software utilities to run to control the headers, with trade names like ASUS Aura Sync, Gigabye RGB Fusion, MSI Mystic Light, etc. These all can deal with BOTH types of mobo headers, depending on what YOUR mobo model has. So the NAME of the control utility does NOT tell you what you need to know. You must match the type of lighting devices you buy - either 4-pin plain RGB, or 3-pin ARGB - to the hardware header your mobo has. So you need to read the specs or the mobo manual for YOUR model to guide your buying of lighted fans or light strips.