Solar Powered Microserver

June 1, 2018 Roberto Rosario Tinkering, Tutorial 0

As you have probably read already, less than a year ago Puerto Rico experienced one of the worst natural disasters in recorded history (https://www.mayan-edms.com/post/hurricane-maria). The situation after hurricane Maria has been compounded by an already deficient energy infrastructure. Frequent blackouts are now a common occurrence of daily life.

Blackouts are not just annoying, but cause a series of problems impacting almost all aspects of modern life. Being a technology worker, blackouts directly impact my bottom line and my primary source of income.

After months in the dark, I took the plunge and built a small solar power system. To make use of solar energy it is very common to use a voltage inverter to boost the 12 volts DC produced by the solar panels and stored by the batteries to 120 volts AC which is what most electronic devices use. Using an inverter introduces some conversion losses in the system. In order to minimize these losses, I started converting as many devices as I could to work with 12 volts DC. This way they could be operated directly from the solar system batteries. It was time to start converting my tools of work too.

One of the systems I need for my daily work are computers and servers. I have some hosted on the cloud and others locally. Constant power outages mean a lot of the charge in my solar system batteries is being wasted keeping the servers and computers working. There had to be a better way to keep the equipment I needed running and optimize their electricity use.

Instead of a few larger computers, I decided to start scaling down the devices I used. More devices meant I could spread the services among them.

Solar Powered server assembled

Single board computers or SBCs are all very common now with a big variety to choose from. These SBCs are usually powered by USB so they already work with DC current. One my favorite single board computers is the ODROID C2. The ODROID C2 is produced by a responsible company, it’s well documented and is very well supported. The ODROID C2 has a 64-bit quad-core ARM CPU, 2 GB of RAM, and support eMMC for storage. It is one of the most powerful SBCs in the market in its price range. With this in mind, I set out to convert some of my existing ODROID and SBCs to replace the common servers and computers I normally use.

Figure 2 - The common plastic and 3D printed enclosures for these SBCs are not enough to protect them and do not leave any space for additional components. Aluminum enclosures are a much better choice

Figure 3 - This is the ODROID C2 with power indicator and button installed. The switch is not connected to anything and left for future use (maybe via GPIO). The power indicator is soldered to heartbeat LED on the board

Figure 4 - The power cable

Figure 5 - The JST plug goes to the voltage converter inside the aluminum box. All cable bonds are protected with heat-shrink tubing

Figure 6 - The Anderson connector goes on the outside of the cable

Figure 7 - I crimped then and added a bit of solder for best conductivity

Figure 8 - Here I am testing for continuity

Figure 9 - I added some heat-shrink tubing to work as cable strain support

Figure 10 - The ODROID mounted using brass standoffs. The residue is from double-sided tape from a previous attempt

Figure 11 - The serial console and power plugs were replaced as shown

Figure 12 - The serial console and power plugs were replaced as shown

Figure 13 - Here is the Voltage converter mounted with double-sided tape. The converter takes the 12 volts from the solar system and reduces it to 5 volts

Figure 14 - This particular converter can supply 3 amps continuously

Figure 15 - Everything mounted and all cables tied properly

Figure 16 - The ESP8266 (ESP-01) programmed to work as a WiFi to serial console bridge. This will allow access to the console of the ODROID even if communications fail. This is perfect for debugging and management

Figure 17 - Here is the box fully assembled. The holes for the USB, network connector and the power button were cut by hand and there was some scuffing. This can be avoided using painters tape or with better tools like a CNC or a bench drill

Figure 18 - The ODROID-C2 supports eMMC storage and this one has a 16 GB card which is used for system files. For storage, an external SSD SATA hard drive is used with a SATA to USB adapter

Figure 19 - The ODROID’s USB ports are USB 2. This means that the access to the storage will not the ultra fast but it is adequate for the work this box will perform

Figure 20 - Here is the microserver placed next to the solar system charge controller and connected to the Anderson power distribution box

For comments, questions, and suggestions, please visit the original article at https://medium.com/@siloraptor/solar-powered-microservers-for-a-post-hurricane-maria-puerto-rico-ca83027d20ac.

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