Solar Panel Project
Penn State has an extensive 3D printing operation housed in the Hammond building. Located there are about ten printers that use additive printing technologies to create parts/objects. Unfortunately, without a wall outlet, the operation shuts down completely. Luckily, the EDSGN 497J class led by David Saint John has started a solar energy project that will allow the whole operation go mobile. We envision a cart that has a solar array attached to it charging a battery in order to power the printer, a monitor and a Raspberry Pi.
This page is to store and organize information on the project and also allow future students to take on the challenge with some support. Please update as things are being completed.
What we have
- Solar Panels: This is the cornerstone for this project. The panels will take the suns energy and turn them into useful electrical energy.
- DC Controller: This is the manager of the whole operation. It will take the inputs from the solar panels and use this energy to charge the 12V battery. If the battery does not need to be charged, it will cut off the energy flow from the panels and wait till it hits a threshold voltage where it will kick on and start transferring the energy.
- 12V Battery: This will be the workhorse of the operation. It will take the energy gathered from the sun to power all the electronics and different accessories needed to print. It will be a marine battery that will supply enough voltage and current to power these electronics.
- Printer: We've got em, just slap one of our working printers on
- Raspberry Pi: Computer that will do a lot of the processing and will allow us to print.
- Monitor: Obviously we have a lot of these. In the future it would be beneficial to try to find a monitor that runs off DC and uses less power. After researching and discussing with classmates, a possible route to go is using the Raspberry Pi monitors like the one below, or trying to get a wifi module onto it to allow it to go to a tablet or something like that. Maybe somebody will rig it so they can connect via Bluetooth with a Bluetooth module for the Pi to get the larger screen? This is the area that should be where time is put into for the future. Definitely find a power saving alternative.
What we need
- A cart: literally the support for all of the above mentioned items and other paraphernalia.
- An assembly to hold the panels: Pretty self explanatory
- Wiring: If we are going to implement the system found below in design, we are going to need more wires! In addition, we might need some structure to house all the electronics that also has plugs so we can turn things off safely and quickly
- Power Inverter: This will be used to power the monitor and Raspberry Pi. We need to make sure that we get an inverter that will be able to handle the power consumption of the electronics. Preferably, the inverter chosen will have at least one USB port on it. This will allow for ease of use.
PhotoVoltaic (PV) Setup
In order for this whole operation to work we need to implement a certain setup. This setup can be seen here:
If we follow this, the DC controller should charge the batteries when need be while the batteries output the necessary DC voltage to the printer.
A problem we are going to run into is the fact that the monitor runs on Alternating Current, which is much different than what our battery will output. Thankfully, this isn't the first time this problem has been encountered. Power inverters, commonly sold for use in cars, take a DC input (our battery) and convert it to an AC output (What our monitor needs). These things can be found on Amazon for pretty cheap. Most people have one laying around and they don't even know.
Another problem is with the output of our battery and the input of the majority of electronics we use. The battery will hopefully output on an average 12V DC depending on the charge (actual ~10.5-14). Now this is okay to power the motors but the Arduino needs 5V DC. As you can imagine, when you mix these two, somethings gonna give and its not going to be the battery. Thankfully there are some smart people out there and we are in luck again. Usually most power inverters have a USB connection port integrated on the component, this will output the necessary 5V. Alternatively, any USB car-phone charger can be modified to supply the 5V.
Below is the layout I would employ to make sure all components are powered correctly.
DC Controller Setup
As a side note, I had to calibrate the DC Controller to suit our needs. The pictures below show what I had to initialize. Please read the manual if you intend to change these settings. In addition to the initialization pictures, I have included a picture of the input/outputs of the controller. Please reference the above picture to figure out what to connect to what. If you intend to change the initialization settings, this might change so read up.
So how will this work? As I have alluded to throughout this whole page, it is theoretically very simple. The solar panels take in the sun's rays, cause the solar cells to react and produce small voltages and currents. Collectively, these cells convert power based on the sun's intensity and will then go to the DC controller. The DC Controller is like a gate to a castle, if the king needs supplies from outside the castle walls, he tells the gatekeeper to open the gate and let them in. If he doesn't need anything, the gatekeeper keeps the doors closed. The same can be applied to our setup. When the battery (king) needs a charge, the DC controller (gatekeeper) opens the gate and lets the supplies (power from panels) in, if it doesn't, the connections are remained closed. From here, the king distributes supplies to his followers. In our case, the battery powers the monitor, Pi, Arduino, and motors.
This sounds very simple and I think it will be. The only thing that the next class has to focus on is making sure all of our components will be powered correctly and safely with stable operation. This can be calculated by checking the power ratings of the inverter and battery and the power consumption of the different loads (printer, monitor)
The progress has been pretty slow on this project this year. Hopefully this year, students will pick up where I left off and continue the project. The majority of what is left to do is gathering parts and making sure they all work together. The next step will be to get a cart and somehow rig it all together. Good Luck!