After doing months of research and experimentation I have finally completed my task. Building a raspberry pi with the ability to running 24/7 outdoors off grid using batteries and solar power.
Why? There are thousands of applications for this kind of setup, here are some I would like to experiment with in the future:
- Mesh network node, over a wide area
- Weather station
- Outdoor wifi hotspot
- Outdoor wireless camera node
- Wifi bridge
Priorities. Project objectives were,
Considering this was a experiment / proof of concept this was put together using things I found around the house, obviously if this was built for commercial applications the housing would need to be built using steel and this would make the costs go up. This was built using the following components and costs:
- Raspberry Pi $49.50
- Raspberry Pi Case $10.85
- Micro USB Cable $1.00
- 12v to USB Converter $5.11
- Solar Charge Controller CMTP02 $12.00
- Solar Panel 60Watt $59.98
- Battery AGM12-20 $65.00
- Total: $203.44
Once I had all to components I used Styrofoam which I found in my garage to build a base which will be located at the bottom of the bucket, the objective will be to hold the battery in place and also insulate it form the suns heat. see below.
Once we have a nice tight fit, we’ll install it in the bucket. I will also use the leftover Styrofoam which I have crusted into small pieces to fill the gap between the battery and the wall of the bucket. This will stop any movement and will also provide insulation to the battery itself.
Now we need to take note, I have completed a similar experiment here where I tested the battery and Raspberry Pi alone without solar or controller. I managed to get 4 days uptime.
Next we will need to run the wires required for the solar panel, I drilled a hole at the bottom of the bucket and brought the wires up to the top. I did this because if water comes through the hole it will stay at the bottom and not harm the electronics.
Next we make another circle with the Styrofoam and fit it on top of the battery, this is where we will house the electronics. Its the safest place as the lid will be water and air tight.
Now we can connect the Solar controller CMTP02 to the battery and to the Solar panel, finally onto the 12v to USB controller.
Bringing it to life! Install the raspberry and have it connect to my home wifi network. Then seal the bucket and setup somewhere in the backyard where it will get the most sun,facing North (In Melbourne).
Now Im will testing this setup, it should run forever like this. During my first setup run, I had connected the solar panel the wrong way due to bad color coding on the cables. Now that its fixed its been running for three days and the battery is currently on fill charge.