Question Can i plug 6 fans into a fan hub?
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JohnBonhamsGhost
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- Jan 14, 2016
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what lot of people?
this has never been an issue with fan/LED hubs or why would they produce them and include them?
a case's fan and/or LED hub is going to be powered usually through a SATA connection.
a 3rd party PWM/aRGB hub will work in the same manner.
this provides more than enough power to run the amount of fans along with theirs or any other aRGB devices.
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What you "heard" was wrong or misunderstood. Here are the why's for limits. This is long, but what you need is here along with extra info.
Just to start, remember that a lighted fan (the current designs of plain RGB or Addressable RGB (ARGB)) are really TWO devices in one unit. Each has a fan MOTOR and some LIGHTS in the frame, and they are powered separately. That is why they have two separate cables to plug into different mobo headers. The MOTOR requires power at 12 VDC, and the LIGHTS require power either at 12 VDC for plain RGB (4-pin), or 5 VDC for ARGB (3-pin). If you look at published specs for these fans they SHOULD tell you the max AMPS for each of those separately, but often they do not. They may give you only one Amps spec, and you are left trying to guess whether that is TOTAL for both parts, or just for ONE (which one?) of those two. As a general rule on most modern fans, the MOTOR part may draw at max from 0.10 to 0.25 A (usually in the lower part of that range). I can't quote a similar spec for the LIGHTS in a "typical fan" but we can make a good guess IF no spec is provided. A rough rule is that ONE LED (or node) in a light string will consume up to 20 mA, or 0.020 A. So if they tell you the NUMBER of LED's in the fan frame, you can calculate the max lighting amps for that one fan from that estimate. Likewise the mobo makers normally do specify in their specs the max current available from EACH fan motor header AND each lighting header separately.
NOTE that an OLDER style of lighted fans called LED Fans has only one colour of lights in it with NO control of how they operate, and only ONE standard fan connection cable to go to a single mobo fan header. The lights on these are merely connected to the same power source as the fan motor and the do increase the unit's max current draw, up to 0.35 to 0.50 A.
Also a small note. ANY fan motor will draw a higher peak current VERY briefly when it first starts from stalled, but an alowance for that start-up surge is already included in the specs of max current use.
A standard mobo fan header can deliver the 12 VDC power for anything plugged into that ONE header up to 1.0 A max current. So normally one header can be used with 4 common fan motors, often more depending on the fan's specs. A similar calculation can be done for the max amps available spec from the mobo lighting header. Thus you can get good estimates of the max loads for motor and for lights separately for whatever number of fans you propose to connect to a single mobo motor header and lighting header.
SPLITTERS and HUBS
These are two devices types that differ in one important detail, BUT makers very often use the terms interchageably when that is wrong! I distinguish them this way. A SPLITTER is a simple device that merely connects all its fans in parallel to the host header lines. Those lines on a 4-pin header are: Ground, +DC Volts supply, Speed Signal (sent from fan back to header), and PWM signal. The SPLITTER has only two types of "arms": a single female connector to plug into a mobo header, and two or more male output connectors where you plug in your fans. It has no other connections. Note that this apples both to fan MOTOR splitters and to fan LIGHTING splitters, although the two different functions require different splitter types. Common SPLITTERS look like groups of cable "arms", but instead they may look like small circuit boards with output ports, or enclosed boxes with holes in their sides for plugs.
A HUB has VERY similar features so distinguishing which is which is not obvious. But there IS an important difference. The HUB will have those two types of connections and cables, but ALSO a THIRD connection that must plug into a power output (either older 4-pin Molex or recent SATA) directly from the PSU. THIS is the power source for all the fans (or lights for that style of Hub) connected to the Hub, so it draws NO power from the mobo host header. Thus the 1.0 A max power limit of the host header does NOT apply to the number of fans you can connect to the Hub. There still is a limit. If the power connector is from a SATA connection, the Hub is limited to 4.5 A max current load in total for all its MOTOR outputs. Often the limit on EACH output port is the same as a normal mobo header. IF the power connection is to a 4-pin Molex, the total current limit is from 5.0 to 8.5 A, depending on the wires used. Those limits apply to either a MOTOR HUB or a LIGHTING HUB. IF the Hub you are using is a combo that deals with both motors and lights in one Hub with a single power cable, it's a little more complicated. HOWEVER, even 4.5 A max for MOTORS at less than 0.25 A per motor is about 20 fans! In practice this means NO limit worries for using one Hub with many fans.
The visual FORM of a HUB may be a collection of cable arms, a circuit board, or a closed box with ports recessed in holes, VERY like the forms of SPLITTERS. The UNIQUE marker of a HUB is the necessary connection to a PSU power output.
Almost all HUBS (I know of one or two exceptions) can be used ONLY with a mobo host header that is using the new PWM Mode of signals, and ONLY with new 4-pin PWM fans. Such devices cannot control the speed of 3-pin fans. A 3-pin fan connected so such a signal set can only run full speed all the time.
The speed of 3-pin fans can be controlled ONLY by varying the VOLTAGE supplied to it from Pin #2 of the header, from 12 VDC for full speed down to about 5 VDC for minimum speed without stalling. A HUB cannot do that type of signalling. On almost all mobos now the fan motor headers are 4-pin. BUT in the configuration screen for each such header modern mobos provide a choice of which way the header operates, called the MODE setting. It may be set manually to use either the older Voltage Control Mode (aka DC Mode) necessary for 3-pin fans, OR the newer PWM Mode ideal for 4-pin fans and needed for use with a HUB. Some also have an "Auto Mode" option that tests the connected fan and sets MODE by itself. This is OK except for the one situation of using a CPU_FAN header to power both a PUMP and the rad fans of an AIO liquid cooling system. In that one situation you need to set the header manually to PWM, and NOT the Auto Mode choice.
So, 3-pin older fan MOTORS and newer 4-pin PWM fan motors require different types of signals to control speeds. IF you have a mix of fan types you need to separate them into two control groups. Connect all your 3-pin fans to a header using the older Voltage Control Mode (aka DC Mode) and use a SPLITTER to connect multiple fans to that header. In doing so you MUST ensure that the max total CURRENT in AMPS limit for the header (1.0 A) is obeyed. Then you can connect all your 4-pin fans to a different header configured to use PWM Mode, and use a HUB for that, connecting its power line to a PSU output. The power limit of the Hub generally will NOT be an issue, and the power limit of the host header is NOT a factor in this case.
Similar considerations apply to any LIGHTING Hubs you may choose. FIRST, remember that plain RGB (12 VDC, 4-pin) and ARGB (5 VDC, 3-pin) lights require very different signals and Voltages, so they are fed from different mobo headers. (In some cases if the mobo does not have the right header for your lights, you may be using a separate third-party Lighting Controller.) Because of that, a LIGHTING HUB will come in either of two styles - there is NO way to mix both lighting types in one circuit and Hub. The Hub will have to plug into the correct mobo header, just as the lights themselves would. (There are a few unique third-party Lighting Controllers that can accept plain RGB signals from a mobo header and "translate" them into ARGB signals so that they can output to ARGB lights as well as to plain RGB lights, so maybe we might consider that a form of "mixed lighting.") In BIOS Setup you can NOT "configure" a mobo lighting header for one style or the other. Each header is fixed to one style.
A small note for both Splitters and Hubs for MOTORS. Each motor sends its speed signal back to the mobo on Pin #3 for measurement and display. The header also monitors that signal for NO signal (or, in some cases, a speed too low) that indicates fan FAILURE. Such an event prompts a on-screen message so you know and can plan to fix. Specifically for CPU_FAN headers, the actions on failure are usually more severe. Failure may cause quick complete shut-down of your system, and also may prevent re-booting until a fan speed signal IS present as you try to start up. A header can deal with the speed signal sent back to it from only ONE fan motor. So any Splitter or Hub will send back to its host header the speed signal of only ONE of its fans. That will be the one output identified by some marker. In the case of the "collection of cable arms" style, the common design is that only ONE of the male outputs has ALL FOUR pins while all others are missing Pin #3. So when you use a Splitter or a Hub you MUST ensure that that one marked output HAS a fan plugged in. And that is the ONLY fan on that header whose speed can be displayed and monitored. You will never see the speeds of the others on that Splitter or Hub. So from time to time YOU should inspect your fans to be sure they all still are working.
Just to start, remember that a lighted fan (the current designs of plain RGB or Addressable RGB (ARGB)) are really TWO devices in one unit. Each has a fan MOTOR and some LIGHTS in the frame, and they are powered separately. That is why they have two separate cables to plug into different mobo headers. The MOTOR requires power at 12 VDC, and the LIGHTS require power either at 12 VDC for plain RGB (4-pin), or 5 VDC for ARGB (3-pin). If you look at published specs for these fans they SHOULD tell you the max AMPS for each of those separately, but often they do not. They may give you only one Amps spec, and you are left trying to guess whether that is TOTAL for both parts, or just for ONE (which one?) of those two. As a general rule on most modern fans, the MOTOR part may draw at max from 0.10 to 0.25 A (usually in the lower part of that range). I can't quote a similar spec for the LIGHTS in a "typical fan" but we can make a good guess IF no spec is provided. A rough rule is that ONE LED (or node) in a light string will consume up to 20 mA, or 0.020 A. So if they tell you the NUMBER of LED's in the fan frame, you can calculate the max lighting amps for that one fan from that estimate. Likewise the mobo makers normally do specify in their specs the max current available from EACH fan motor header AND each lighting header separately.
NOTE that an OLDER style of lighted fans called LED Fans has only one colour of lights in it with NO control of how they operate, and only ONE standard fan connection cable to go to a single mobo fan header. The lights on these are merely connected to the same power source as the fan motor and the do increase the unit's max current draw, up to 0.35 to 0.50 A.
Also a small note. ANY fan motor will draw a higher peak current VERY briefly when it first starts from stalled, but an alowance for that start-up surge is already included in the specs of max current use.
A standard mobo fan header can deliver the 12 VDC power for anything plugged into that ONE header up to 1.0 A max current. So normally one header can be used with 4 common fan motors, often more depending on the fan's specs. A similar calculation can be done for the max amps available spec from the mobo lighting header. Thus you can get good estimates of the max loads for motor and for lights separately for whatever number of fans you propose to connect to a single mobo motor header and lighting header.
SPLITTERS and HUBS
These are two devices types that differ in one important detail, BUT makers very often use the terms interchageably when that is wrong! I distinguish them this way. A SPLITTER is a simple device that merely connects all its fans in parallel to the host header lines. Those lines on a 4-pin header are: Ground, +DC Volts supply, Speed Signal (sent from fan back to header), and PWM signal. The SPLITTER has only two types of "arms": a single female connector to plug into a mobo header, and two or more male output connectors where you plug in your fans. It has no other connections. Note that this apples both to fan MOTOR splitters and to fan LIGHTING splitters, although the two different functions require different splitter types. Common SPLITTERS look like groups of cable "arms", but instead they may look like small circuit boards with output ports, or enclosed boxes with holes in their sides for plugs.
A HUB has VERY similar features so distinguishing which is which is not obvious. But there IS an important difference. The HUB will have those two types of connections and cables, but ALSO a THIRD connection that must plug into a power output (either older 4-pin Molex or recent SATA) directly from the PSU. THIS is the power source for all the fans (or lights for that style of Hub) connected to the Hub, so it draws NO power from the mobo host header. Thus the 1.0 A max power limit of the host header does NOT apply to the number of fans you can connect to the Hub. There still is a limit. If the power connector is from a SATA connection, the Hub is limited to 4.5 A max current load in total for all its MOTOR outputs. Often the limit on EACH output port is the same as a normal mobo header. IF the power connection is to a 4-pin Molex, the total current limit is from 5.0 to 8.5 A, depending on the wires used. Those limits apply to either a MOTOR HUB or a LIGHTING HUB. IF the Hub you are using is a combo that deals with both motors and lights in one Hub with a single power cable, it's a little more complicated. HOWEVER, even 4.5 A max for MOTORS at less than 0.25 A per motor is about 20 fans! In practice this means NO limit worries for using one Hub with many fans.
The visual FORM of a HUB may be a collection of cable arms, a circuit board, or a closed box with ports recessed in holes, VERY like the forms of SPLITTERS. The UNIQUE marker of a HUB is the necessary connection to a PSU power output.
Almost all HUBS (I know of one or two exceptions) can be used ONLY with a mobo host header that is using the new PWM Mode of signals, and ONLY with new 4-pin PWM fans. Such devices cannot control the speed of 3-pin fans. A 3-pin fan connected so such a signal set can only run full speed all the time.
The speed of 3-pin fans can be controlled ONLY by varying the VOLTAGE supplied to it from Pin #2 of the header, from 12 VDC for full speed down to about 5 VDC for minimum speed without stalling. A HUB cannot do that type of signalling. On almost all mobos now the fan motor headers are 4-pin. BUT in the configuration screen for each such header modern mobos provide a choice of which way the header operates, called the MODE setting. It may be set manually to use either the older Voltage Control Mode (aka DC Mode) necessary for 3-pin fans, OR the newer PWM Mode ideal for 4-pin fans and needed for use with a HUB. Some also have an "Auto Mode" option that tests the connected fan and sets MODE by itself. This is OK except for the one situation of using a CPU_FAN header to power both a PUMP and the rad fans of an AIO liquid cooling system. In that one situation you need to set the header manually to PWM, and NOT the Auto Mode choice.
So, 3-pin older fan MOTORS and newer 4-pin PWM fan motors require different types of signals to control speeds. IF you have a mix of fan types you need to separate them into two control groups. Connect all your 3-pin fans to a header using the older Voltage Control Mode (aka DC Mode) and use a SPLITTER to connect multiple fans to that header. In doing so you MUST ensure that the max total CURRENT in AMPS limit for the header (1.0 A) is obeyed. Then you can connect all your 4-pin fans to a different header configured to use PWM Mode, and use a HUB for that, connecting its power line to a PSU output. The power limit of the Hub generally will NOT be an issue, and the power limit of the host header is NOT a factor in this case.
Similar considerations apply to any LIGHTING Hubs you may choose. FIRST, remember that plain RGB (12 VDC, 4-pin) and ARGB (5 VDC, 3-pin) lights require very different signals and Voltages, so they are fed from different mobo headers. (In some cases if the mobo does not have the right header for your lights, you may be using a separate third-party Lighting Controller.) Because of that, a LIGHTING HUB will come in either of two styles - there is NO way to mix both lighting types in one circuit and Hub. The Hub will have to plug into the correct mobo header, just as the lights themselves would. (There are a few unique third-party Lighting Controllers that can accept plain RGB signals from a mobo header and "translate" them into ARGB signals so that they can output to ARGB lights as well as to plain RGB lights, so maybe we might consider that a form of "mixed lighting.") In BIOS Setup you can NOT "configure" a mobo lighting header for one style or the other. Each header is fixed to one style.
A small note for both Splitters and Hubs for MOTORS. Each motor sends its speed signal back to the mobo on Pin #3 for measurement and display. The header also monitors that signal for NO signal (or, in some cases, a speed too low) that indicates fan FAILURE. Such an event prompts a on-screen message so you know and can plan to fix. Specifically for CPU_FAN headers, the actions on failure are usually more severe. Failure may cause quick complete shut-down of your system, and also may prevent re-booting until a fan speed signal IS present as you try to start up. A header can deal with the speed signal sent back to it from only ONE fan motor. So any Splitter or Hub will send back to its host header the speed signal of only ONE of its fans. That will be the one output identified by some marker. In the case of the "collection of cable arms" style, the common design is that only ONE of the male outputs has ALL FOUR pins while all others are missing Pin #3. So when you use a Splitter or a Hub you MUST ensure that that one marked output HAS a fan plugged in. And that is the ONLY fan on that header whose speed can be displayed and monitored. You will never see the speeds of the others on that Splitter or Hub. So from time to time YOU should inspect your fans to be sure they all still are working.
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