SOLAR POWERED SERVERS?
Right from the top let me clear up one consistently echoed misconception regarding the purpose of this little solar project. The primary goal of building this solar system was NOT to gain any sort of return on investment (ROI). I built this solar system because I have had a fascination with Photovoltaic energy production and off-grid power systems for the past couple years. Until recently I have never really had the funds available to build something like this and even so this project still had a pretty tight initial budget (which was surpassed after I decided that I needed to add another panel and battery to the setup).
This system is a precursor to building a larger scale PV system which will hopefully serve to power my archives web server and soon to be NAS (I still have not gotten around to setting that up 😐 ). I want to be a little greener as both an individual and as a blog / YouTube channel and pulling two servers off the grid which consume power 24/7 is a great way to do that. As an added bonus I will also be pulling the cost of running my servers off my parents electrical bill, they do not consume a whole lot of electricity and subsequently do not cost very much to run but it is still a benefit from building this system nevertheless.
I am building a small scale, cheaper, solar setup first because I want to get a feel for what it is like to maintain and build a completely off grid system which is intended to run 24/7 for an indefinite amount of time. This setup was built to power a Pi-top CEED with an ODROID C2 SBC inside, 2x LED lights (1x 13W bulb and 1x 6W bulb), and a phone charger. All of this will be running through an inverter but I do intend on powering my servers directly off 12V with the final system in order to ensure maximum efficiency.
In this article I will talk about the equipment I used, touch on how I went about setting everything up, and mention any problems I experienced during the build. If you want to try and build a similar system you can find all of the components I used at the bottom of this article. I have included A TON of HD images in this article so you can put together a better picture of what exactly the final product looks like. This is not meant to be a comprehensive guide on how to build a solar system and I am NOT an expert when it comes to building PV systems! That being said, if you have any tips for me feel free to leave a comment!
Just something to note before I start talking about the setup. I was originally using only a single panel and a single 20AH battery. After two weeks of use I realized that I had sized the system too small so I added an additional panel and another 20AH battery.
Let’s start out with the primary component of a solar system, the solar panels. I am using 2X Synthesis power 50W polycrystalline panels which I bought off eBay for $60 a piece. The power system is comprised of 2x ExpertPower 12V 20AH SLA batteries ($38.00 each), a Docooler (generic) 12V 20A charge controller ($10), and a GoPower 175 Watt square wave inverter. I chose to go with some really cheap 12 gauge CCA speaker wire to connect everything together, this is just a temporary solution and I suggest that you use higher quality pure copper marine grade wire instead. The entire power system (minus the extra battery) is housed in an electrical enclosure box which was surprisingly expensive ($25), I could not find a cheaper enclosure of the same size anywhere else. What I would suggest using as an alternative to the plastic enclosure is a old PC case. All of the components I used including the extra battery could easily be consolidated into an old ATX computer case. The components were mounted inside the case using industrial strength Velcro ($6.50) Two volt meters were mounted to the outside of the case to measure battery and input voltages ($3.50 a piece). To make the outdoor and indoor connections I bought a bag of standard MC4 connectors. I connected the two 50W panels together in parallel using MC4 Y connectors ($7.50). There are also a couple other odds and ends that I used such as fuse holders and additional connectors, all of which can be seen in the pictures below and in the parts list.
I started off by building the primary power system. First, I drilled out two holes on the side of the electrical box for the voltage meters. I then laid out where everything would go using industrial strength Velcro. I placed the other side of the Velcro on each component and installed the battery and charge controller into the case first. At this point I connected the battery and voltage meters to the corresponding charge controller terminals. I then ran a pair of wires with MC4 connectors attached to the ends from the charge controller with a 10A in-line fuse to the outside of the electrical box through a pre-drilled hole in the top. This pair of wires will connect to the wires running from the solar panels. Next I installed the 175W inverter, for this I used a 12V car socket to eyelet terminal adapter with a 20A in-line fuse to connect the inverter directly to the battery. Finally I hot glued the volt meters into the case and cleaned up some of the internal wiring using Velcro straps. The second battery was installed several weeks later, all I did was connect it in parallel with the battery inside the enclosure through the pre-drilled hole on the top of the electrical box.
I did not really have a choice in the location of the solar panels. I was given permission to build in a specific location and in that location only. It works, but there are definitely better places to mount a solar panel. The panels get direct sunlight for about 5 hours out of the day.
The mounting solution is pretty basic but it gets the job done and has currently weathered 2 tropical storms and Hurricane Matthew. The central wood beam is buried approx. 2.5 feet below ground and is encased in cement. Both panels are mounted at an angle which has not been calculated to be optimal. Do you see how the bottom panel is mounted? Don’t mount the panels like that, the bottom mounting solution puts too much stress on the central beam and has caused a substantial crack to develop along a large section of the support column. The way the top panel is mounted is much better, it is more secure and puts a lot less stress on the center column. I will have to change the way the bottom panel is mounted when I have time.
The panels were connected in parallel using the MC4 Y connectors and the wires were secured to the post using staples and zip ties. I routed the wires underground and then through a hole on the side of the house where a water spicket pokes out. I then went under the house and routed the cable through a HVAC vent, into my room, and to the power system. I connected the MC4 connectors together and …………………………………… nothing happened. One of the MC4 connectors was not properly put together (my bad). After fixing this issue I connected the system to the panels again and to my delight the “charge” light on the charge controller emitted a light green glow and the input volt meter jumped to 16V!
A BIG THANKS TO MY FATHER WHO HELPED OUT A LOT WITH THE MOUNTING SOLUTION!
After everything was working I plugged in a power strip, Velcroed it to my desk and plugged everything in. I soon found out that the system was too small for what I was demanding from it so I added an additional 50W panel and another 20AH battery. For the most part the final system has been working great over the past couple months. However, there have been a few times where there has been consistent cloud cover for over a week and since the panels produce next to nothing in indirect sunlight the system was completely depleted within a matter of days. Currently I am considering the possibility of turning this into a hybrid system by adding a couple small wind turbines to it. This modification would allow the system to produce some power during long periods of cloud cover assuming that wind speeds are adequate.
- Synthesis Power Solar Panels
- Expert Power 20AH 12V Batteries
- Docooler Charge Controller
- 10 Pack MC4 connectors
- Cheap CCA Wire (I suggest using higher quality wire)
- Go Power 175Watt Power inverter
- 12V Socket Adapter, Eyelet Terminals
- ATC Fuse Holder
- Velcro Cable Ties
- Electrical Box
- MC4 Parallel Y-Connectors
- Volt Meters
- All parts for the solar panel supporting structure along with a box of ATC fuses were purchased from Home Depot