Miniature Cloud Project – Providing Power

Posts in this series
  1. Building a Miniature Cloud Platform
  2. Miniature Cloud Project - Providing Power
  3. Miniature Cloud Project - Networking
RaidmaxSpecs

Raidmax 500W Specifications

Providing Power

Since I am grabbing a number of different technologies from a bunch of different sources, they all have different power requirements.  Using the vendor provided power cables and transformers for this project would quickly become a mess and I would have to deal with each type of adapter/transformer separately.  This is less than ideal.  Fortunately the computing industry has been handling this problem elegantly for decades and I determined that the easiest thing to do here would be to add an ATX style PSU in place of the defaults.

RaidmaxPackage

Raidmax 500W Candy Box

 

I purchased a Raidmax 500W ATX PSU from Newegg.  It provides the following power to these rails:

  • +3.3V@20A – not used
  • +5V@20A – Raspberry Pis & Network Hardware
  • +12V@32A – NUC Blades & Cinder Rack
  • -12V@0.5A – not used
  • 5VSB@2.5A – not used

 

I am removing the leads to the power outputs that I do not need.  Following the pinout for the motherboard connector, we find the main 12V rail that we want to use.  This is where we want to pull our NUC power from since they are the biggest power consumers in this setup, and this rail is designed to power the main CPU on single board, making it the most robust of our options to pull from.  Since the NUC devices want 19V power like a laptop would normally consume, and although I have read that the NUCs CAN be powered by 12V but they make strange noises at the lower voltage, I decided it is best to just give them what they want and prevent us from making problems later.  Just as we are able to increase the voltage from the USB 5V rail for our 12V low amperage devices, we can do the same with the 12V rail to boost it up to what the NUCs are expecting.

This transformer from Ebay.com claims to provide up to 285W of 19V power from our 12V rail.  This unit cost less than $20.  Since the NUCs ship with up to a 60W power supply, this should keep us under our amperage budget with plenty of room to spare.

12vTo19vTransformer

DC 12V to 19V Step-up Transformer

I purchased a pack of DC Male Pigtail Power connectors for the connections to the NUCs to solder to the 19V output of the transformer because the ones I had didn’t fit, but these are incorrect as well.

In addition to the NUCs, we need a sensible way to manage the power outputs for the USB 5V rail connections and I purchase a generic 5V USB distribution block with individual rocker switches to handle this.

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