I found a perfect sized enclosure for the circuitry.

I soldered the Boarduino together for future use.

I tested all the solar cells and found that they all work, and that they all deliver about 2.0 V in direct sunlight (in the late afternoon). This is with no load; the voltage should drop some with a load. Since I have 10 cells in series it should be around 20V.

I soldered 5 of the 10 panels together in a string that folds up. Tomorrow I'll test the whole string in direct sunlight and solder together a second string of 5, and then I'll put the two strings together. All the cells will be in series.

I need to find a source for a TPO (thermoplastic olefin) or TPU (thermoplastic urethane) transparent coating that is suitable for these solar cells. I am thinking about looking in my local hardware stores for something I can just paint on. It just needs to have a the right chemicals, not have any corrosive stuff at all, and withstand UV light for a good 20-50 years. I'll also look around online to see what films are available.

Also, I found that I don't need the LM317 part of the circuit anymore since I can simply adjust the pot if I need 18V rather than 19V – that step-up converter has constant output voltage even if you vary the input voltage, so my laptop won't get fried even if I overcharge the battery. But I still need a decent 10kΩ pot (or digital pot, eventually) for the other voltage converter because it doesn't give a constant 13.8V output to charge the battery.

I've also been working on the RPI lapdock. I got my HDMI adapter and soldered two jumper wires to splice the USB signal while still getting power to the microUSB of the RPI. I may need to add a switch to turn the USB power to the RPI on and off. I also need to figure out how to configure the RPI startup menu so I can successfully boot onto the lapdock. Plus whatever sequence of things I need to do to start it up. And I still need to re-route the USB and Ethernet. Desoldering is terrrrrible.