First time using backplane - Need assist with understanding molex power limitations

[sirrasmusdk]

Hi everyone

 

I am soon getting my first propper rack server, currently running in a Fractal node 804.

I will be getting the Inter-Tech 4424, should be identical to the roughly equal serial name of Norco/Logic case.

https://www.inter-tech.de/en/products/ipc/storage-cases/4u-4424

 

I have had a hard time understanding exactly how many backplanes (1x plane = 4 drives) i can power with each 6pin molex cable from my PSU.

Currently using this PSU: https://www.corsair.com/us/en/Categories/Products/Power-Supply-Units/Power-Supply-Units-Advanced/RM-Series™-80-PLUS-Gold-Power-Supplies/p/CP-9020196-NA

 

Am i correct in understanding that i can at maximum power 1 plane/4drives per 6pin connection to the PSU?

If that is the case, i feel like i need to upgrade my PSU.

What type of PSU should i aim for, with 24 drives/6planes in mind?

I dont have redundant powersupply support on the planes, so that is not a priority.
I saw a post on PSUs stickied from 2011, but i would assume a bit has changed since then?
 

[JorgeB]

1 minute ago, sirrasmusdk said:

each 6pin molex

What do you mean by 6pin molex? Molex is 4pin.

 

[sirrasmusdk]

The 4pin molex connectors are connected to a 6pin that goes in the PSU, no?

I believe i have 4 molex connectors per 6pin

 

 

Edited September 19, 2022 by sirrasmusdk

[JorgeB]

You mean the cable in the other end? Still only 4 pins are used, and it's not standard for modular PSUs, ideally you need as many molex plugs as there are in the backplane, avoid using splitters, you should be able to get another modular molex cable for the PSU if needed, just make sure it's the correct one for that PSU, as mentioned there are no standards, and even PSUs from the same brand can use different cables.

[sirrasmusdk]

The one i put into the PSU is a 6pin adapter, how many wires there are inside i cant say.

I know i need to occupy all molex slots in the backplane (1 per backplane) but how many can i power with each cable from the PSU? My Molex cables have 4 molex connectors, per PSU connector.

[JorgeB]

Just now, sirrasmusdk said:

My Molex cables have 4 molex connectors

 

4 minutes ago, JorgeB said:

ideally you need as many molex plugs as there are in the backplane, avoid using splitters

So that one is good for 4.

[sirrasmusdk]

So i can run 16 drives per PSU plug?

[JorgeB]

One molex plug won't power 16 drives, should power 4, if you mean one PSU cable then yes, you can run 16 drives from one.

[sirrasmusdk]

Sweet that was my question, i was worried i had to go out and buy an insane Power supply in order to run 1 PSU cable per backplane.