Undervolting Yate Loons

[thilanliyan]

Is it possible to undervolt my Yate Loon fans (they say "D12BL-12" on the sticker) to 5v? I tried it but it doesn't seem to work. I just removed the 12v and the ground right beside the 12v leaving the 5v line and one ground but it doesn't seem to work. Is this too low a voltage?

I tried giving 7v also and that seems to work but I've heard it's bad for the PSU to do the 7v mod since you're feeding some voltage back into the PSU so I don't really wanna use that. Anyone have any input on the 7v mod?

 

[JBDan]

I've done the 7V mod on several fans with no ill effect. But that's just me. If you do the 5V mod and hook it up can you help the fan (with your hand) and it will then start? If so then they obviously have trouble starting @ 5V and it is not recommended to do that mod on that particular fan. Could you use speedfan and connect the fan to a mobo header or is that an option?

 

[thilanliyan]

No I tried helping the fan start and that didn't work so I can't figure out what I'm doing wrong. The fans I'm using have the 3-pin header separately on them (along with the molex connector)...is there anything different you have to do?

Motherboard header isn't an option unfortunately. THanks for your input.

 

[JBDan]

From the way you described you did it correctly. But instead of me trying to put into words how I learned my fan mods I'll give ya a link. http://www.silentpcreview.com/article6-page1.html Or maybe you have already seen this, but pictures to me speak a thousand words hehe.

 

[thilanliyan]

Lol, that's the guide I was following. Okay let my try another brand fan to see if that works. What exactly is it that can harm your PSU when you do the 7 mod anyway. Even in that silentpcreview guide they give a warning about it.

 

[Navid]

Originally posted by: thilan29
Is it possible to undervolt my Yate Loon fans (they say "D12BL-12" on the sticker) to 5v?

That would be very unlikely.
That particular fan is a low-RPM fan. That's what the letter "L" stands for in the name. So, the fan already has a resistor in series with the motor. So, the motor does not get 12V even when you apply 12V to the fan.

That fan is already quiet and does not move much air. Why do you want to further lower its speed.

Anyway, you need more than 5V on that fan.

 

[JBDan]

Originally posted by: thilan29
Lol, that's the guide I was following. Okay let my try another brand fan to see if that works. What exactly is it that can harm your PSU when you do the 7 mod anyway. Even in that silentpcreview guide they give a warning about it.

heh I figured you'd seen that link just makin sure 😉 The little "blue square" text area tells ya. Basically it's about what you said earlier. Feeding volts back into the PSU. "you need to have other loads on that 5V lead, which suck out more current than you feed to that lead from the 12V lead." btw nice mod on your case.

 

[thilanliyan]

Okay I figured out what it was...because of the way those Yate Loons are wired (due to the 3-pin header), you have to actually take out the 12v line from the female connector and replace the 5v line with the 12v line (rather than just removing the 12v line like on some other fans) and then it works. The fans are almost inaudible now and push an acceptable amount of air.

 

[JBDan]

Originally posted by: thilan29
Okay I figured out what it was...because of the way those Yate Loons are wired (due to the 3-pin header), you have to actually take out the 12v line from the female connector and replace the 5v line with the 12v line (rather than just removing the 12v line like on some other fans) and then it works.

Nice! 😉

 

[Navid]

Originally posted by: thilan29
What exactly is it that can harm your PSU when you do the 7 mod anyway.

Current flows from the 12V rail through a 7V-mod fan to the 5V rail (12V -5V =7V).

If the load you have on the 5V rail, in your PC, is less than the fan current, the 5V rail regulator must be able to accept a current flowing into it (opposite direction current usually flows in a regulator). Not every regulator can operate that way. Then, there may be a problem.

Many who use the 7V mod do it because they know that their hard drives load their 5V rail enough. Much more than the fan current. Then, there will be no possibility of a problem since the current will flow in the regular direction.

 

[thilanliyan]

Originally posted by: Navid

Originally posted by: thilan29
What exactly is it that can harm your PSU when you do the 7 mod anyway.

Current flows from the 12V rail through a 7V-mod fan to the 5V rail (12V -5V =7V).

If the load you have on the 5V rail, in your PC, is less than the fan current, the 5V rail regulator must be able to accept a current flowing into it (opposite direction current usually flows in a regulator). Not every regulator can operate that way. Then, there may be a problem.

Many who use the 7V mod do it because they know that their hard drives load their 5V rail enough. Much more than the fan current. Then, there will be no possibility of a problem since the current will flow in the regular direction.

Do the HDDs have to be on the same line (ie. piggybacked on the same plug as the 7v fans?)

Or just have enough HDDs to draw enough current overall from the 5v line? I have 3 HDDs in my system right now...is that sufficient?

 

[Navid]

Originally posted by: thilan29

Originally posted by: Navid

Originally posted by: thilan29
What exactly is it that can harm your PSU when you do the 7 mod anyway.

Current flows from the 12V rail through a 7V-mod fan to the 5V rail (12V -5V =7V).

If the load you have on the 5V rail, in your PC, is less than the fan current, the 5V rail regulator must be able to accept a current flowing into it (opposite direction current usually flows in a regulator). Not every regulator can operate that way. Then, there may be a problem.

Many who use the 7V mod do it because they know that their hard drives load their 5V rail enough. Much more than the fan current. Then, there will be no possibility of a problem since the current will flow in the regular direction.

Do the HDDs have to be on the same line (ie. piggybacked on the same plug as the 7v fans?)

Or just have enough HDDs to draw enough current overall from the 5v line? I have 3 HDDs in my system right now...is that sufficient?

Just have enough ........
There is only one 5V rail.

 

[Zepper]

The D12SL has no dropping resistor - the Nexus that is based on it does. The working voltage range on these cheap, sleeve bearing fans is usually stated as 7 to 12V, but Yate Loon does not specify. It would be easy enough to calculate the resistor needed to drop the voltage to 7V at the motor and the wattage rating the resistor would have to be - much safer to use a resistor than to put the fan between the 5 and 12V lines. At 7V you would be sure the fan would start every time plus you get significantly more air for little or no noise increase. Several sites have reviewed these and have graphs of CFM and dB relative to the applied voltage. Useful to take a look at them.

.bh.