Please help me understand how power supply works for sata rails.

[Captain Brazuca]

So far I have read that:

1. Sata rail max out at 4.5amps for each rail. 

2. There is a max load of 25amps on the 5v.

3. Corsair says that each 120 QL fans are 0.35amps, but DevBiker did some tests and at 100% white it seems that it draws 0.53 amps each fan.

4. LED strips draw 0.36 amps according to DevBiker.

Are those correct, or I’m miss understanding something. 
 

So here is what I need to power: 

 

But if the above is right, how should I power this without risking overloading the sata rails. 
 

On the command core xt alone, if DevBiker measurements is correct then 6 x 0.53 =  3.18 amps + 4 x 0.36 = 1.44 amps, for a total of: 4.62 amps. 
 

Just there I’m over the limit. Is this correct or I’m not understanding something. Thanks

[LeDoyen]

4.5A max on 5V per SATA connector : If your PSU cable has 4 SATA connectors, it's 4 x 4.5A

If you want to do white lighting, i wouldn't worry too much about power draw. you'll end up popping leds in weeks to a couple of months if you do not reduce brightness unfortunately, and even reduced, the heat may still damage them.

If you do not use constant white, the power draw decreases a LOT, even at full brightness.

 

just to illustrate i looked at the power draw on my build (9 fans, 4x21 led strips in the case, 2 waterblocks + reservoir + case strips, plus 6 strips around the desk.. )

that's the power draw on the 5V rail :

RGB off : 3.25A

default RGB cycle : 5.6A (2.35A just for RGB)

All white : 8.7A (5.45A just for RGB)

Sooo.. if you don't care about white, don't worry. If you do want a white build, i wouldn't advise doing it at full brightness anyway to lengthen the LEDs lifespan, and that would obviously reduce power draw. On paper it's a small overload

[Captain Brazuca]

28 minutes ago, LeDoyen said:

4.5A max on 5V per SATA connector : If your PSU cable has 4 SATA connectors, it's 4 x 4.5A

If you want to do white lighting, i wouldn't worry too much about power draw. you'll end up popping leds in weeks to a couple of months if you do not reduce brightness unfortunately, and even reduced, the heat may still damage them.

If you do not use constant white, the power draw decreases a LOT, even at full brightness.

 

just to illustrate i looked at the power draw on my build (9 fans, 4x21 led strips in the case, 2 waterblocks + reservoir + case strips, plus 6 strips around the desk.. )

that's the power draw on the 5V rail :

RGB off : 3.25A

default RGB cycle : 5.6A (2.35A just for RGB)

All white : 8.7A (5.45A just for RGB)

Sooo.. if you don't care about white, don't worry. If you do want a white build, i wouldn't advise doing it at full brightness anyway to lengthen the LEDs lifespan, and that would obviously reduce power draw. On paper it's a small overload

Never thought this was an issue LeDoyen, as my previous build have 4 fans 140 fan from fractal design, (nothing like the QLs) and for 120 LL and 4 strips, I have them on white full brightness for over 3 years now (my last build was in the end o 2019) and they are still going strong. But I believe you and it’s unfortunate to hear that. I know you have a lot more experience than I do, I have read few messages that you posted looking to find out if I could use sata power cable from a RM850x that I have laying around to split the power on a HX1500i. 
Which I believe I can right? Making sure hehe 

So when you say per connector, one cable has 4 split. Each split is a connector in that case?

So one cable could handle 18 amps?

Or 

A direct connector at the PSU? And I would have to use a cable for each? Because that’s what I’m understanding so far. That the PSU could handle it, but I just have to use more than 2 cables.

[LeDoyen]

The PSU connector is something else yes. so a 4 split sata cable can deliver 4x 4.5A on 5V, 4.5A per sata connector.

You can reuse the sata cable from the RMx yes. i don't remember if that one is type 3 or 4 but they are the same pinout anyway for sata, so it doesn't matter. it works.

For the leds on white, it depends on the led chips used i guess. some fans work well, some burn up fast. I did use white on LL fans in the past without problems, but it seems to be an issue with QL fans, but i don't know if Corsair adressed that yet. I also did burn up quite a few corsair strips. but that's not corsair specific. when you cover leds with silicon for waterproofing, they also run warmer. You can feel that if you poke them while lit. on white they are warm, on any other color, they run cooler.

 

Not everyone complains about it so i guess it works for some ^^ but hold on to your proof of purchases in case you have to RMA some fans.

 

Edit : if one single cable could theorically carry the whole 18A, it's often adviseable to split the load across several cables, because of voltage drop on the 5V rail.

Sometimes you may notice some LEDS light slightly dimmer because of that. so if you have several SATA cables with the PSU, they may come in handy. better work with some margin than sticking to the max rating.

 

Edited January 2 by LeDoyen

[Captain Brazuca]

I’m really appreciate your input. I was reading the whole time that it was 4.5 for each cable not realizing was each connector. Still like you said I’ll split them in 3 different cables and will set white profiles to a dimmer settings. Learned something new today. Ty so much

[Captain Brazuca]

Wow reading that thread makes me fell really sad about investing in theses fans lol

[LeDoyen]

remember those who don't have problems don't come to post everything is working great 😛