Saturday, December 12, 2015

NAS Box - the PSU

The short version is:
I was able to grab used Enermax Pro82+ for 25$!

The long version is:
Good PSU for this build is a key. Most so called, "expert bloggers" who only write about things not build them.. recommend 80Plus Gold - their are WRONG.

80Plus certifies products that have more than 80% energy efficiency at 20%, 50% and 100% of rated load. If your Nas box will require only 10%-15% of the base Wattage - then guess what 80% or more efficiency standard does not cover it. My build aims for 30-50W which is less than 20%, 80Plus Gold certificate does not cover it.

80 Plus test type[4] 115V internal non-redundant 230V internal redundant
Percentage of rated load 10% 20% 50% 100% 10% 20% 50% 100%
80 Plus
80% 80% 80%

80 Plus Bronze
82% 85% 82%
81% 85% 81%
80 Plus Silver
85% 88% 85%
85% 89% 85%
80 Plus Gold
87% 90% 87%
88% 92% 88%
80 Plus Platinum
90% 92% 89%
90% 94% 91%
80 Plus Titanium 90% 92% 94% 90% 90% 94% 96% 91%

Perfect example is be quiet! Straight Power 10 CM 800 W- 100$+, at 50W I will get75% efficiency even though it is 80Plus Gold.

After going over serie of reviews and tests. I went for Enermax 385 Pro82+, because it's efficiency is similar at 30-50W, and second hand costs 25$!

During my research, I found another solution, which is often recommended by "so called experts". There is a solution  which is called PicoPSU dedicated for small ITX boards. People say it has 96% efficiency or more. And that is correct, but the disadvantage is you have to feed it with external 12V PSU  (like AC DC 12V 8A 96W) which will have 85% efficiency at full load. Overall You will get 80%+ efficiency at 90W+ and additional adapters for SATA power. It is not worth it if you have enough space for the Full ATX build.

If you can't get Enermax for cheap, check out one of the FSP power supplies, they are worth consideration.

I've reached Enermax to ask if it's relevant for power efficiency to connect everything to one 12V line. They've replied next day. The short answer is - it does not matter how you connect it.

Pro tip from Enermax, how to determine which cables are from which power line?
Whole yellow cable - current line nr 1,
Yellow cable with black stripe - line nr 2.

Thanks, Enermax!


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