After some days of testing and wire cutting, I advanced slightly on my quest to power a raspberry pi from a solar panel.
Solar panels are supposed to stay outside (duh), therefore you won’t want to connect your stuff like this:
As my panels are going to stay on my balcony, where it does not rain, water is not an issue, but testing all this shit and connecting and disconnecting things is. So I decided to do things properly and buy the MC4 connectors. They are one of the standards for solar panels, and both my panels use it. This is how they look like:
MC4 connectors and Y-connectors for connecting them in parallel. Remember kids, connecting panels in series increases the current, connecting in parallel does not.
I will post how they look like in my rig and how to connect them later.
My solar panels provide 36V, which is enough to fry my raspberry pi and my miners. I have to move it down to something more manageable. I have to power two kinds of devices: the 12V usb hub that will power the small miners, the big miners (big challenge), and the PI itself from USB. So I am talking about converting both to 12V and 5V.
I could just connect more USB hubs to 12V and have only one step down from 36V, but I am willing to try also with direct power. So, I got two things:
- A DC 36V-to-12V regulator, which I put inside an electric case, to give it some protection. Link to amazon:
- A 4.5-40V 12V To 5V/2A buck regulator. Link to product on amazon:
The first one can convert from any input to anything between 1.25 all the way up to 36V. There is a little screw where you can set the output current. You can see it on the lower right corner.
The second one has a display showing me the input voltage, and directly a USB connector, so I got it for the convenience.
It cannot charge an iphone directly, though, as the iphone needs an identification resistor.
In theory, this should be enough to power my stuff. But that’s not what it happens. As soon as I connect everything, this is what it happens. I haven’t checked why yet, as I had to come to work. I will post updates this weekend. (Probably I didn’t follow the instructions shown at the amazon website)