Hacking a PVL-68
This can be done, I have discected a PVL-68 to create a foldable solar panel to use while in the back country. Reassembling it as a 2 X 2 array of 3, 3, 3, and 2 panels.
Doing so is not especially technically difficult, but is a bit involved mechanically. The biggest challenge is dealing with the three electrical busses that run down each side of the array, and the bypass diodes.
The PVL-68 is arrayed as 11 panels wired in series. More accurately, each panel is actually 2 cells. Each of the cells is wired independently on either side of the panel. The two series strings of cells are wired in parallel at the connector end of the array. Each cell has a bypass diode for a total of 22 cells and 22 diodes in the array.
I cut a PVL-68 into for segments of 3, 3, 3 and 2 panels. The 2 panel segment included the junction box and external connector cables.
Looking closely at a PVL array, it is easy to see the physical edges separating each panel, so slicing between the panels at the junction line is straight-forward - until you get to the edges, where the bypass diode and conductive busses transect the panel separator line.
The PVL series arrays are very well made. From the back is the cold-bonding mastic which allows these panels to 'peel and stick' to metal (and other) surfaces. The mastic is sticky (surprise!) but easy to scrape away. Above the mastic layer is a very tough plastic membrane which is the bottom mechanical substrate and covers the bus strips, diodes, and photo diode grids. The plastic membrane is harder to remove - it's tough, and well bonded to the layer above - but can be cut away with a razor knife and patience. You will need to cut away this membrane in the areas where the busses need to be exposed for disconnection of the bypass diodes, and eventual rewiring.
You must decide on an approach to disconnecting the diodes, and severing the conductive busses. Looking closely at the array from the top, you will notice 'bumps' in the top membrane on either side of the array right at the dividing line between adjacent panels. These 'bumps' are the bypass diodes. For the purposes of cutting the array into sections, the diodes are very inconveniently located.
If you choose to preserve the diodes for use in rewiring the array segments, then you will need to dig into the back of the panel, 'excavating' through the membrane around the perimiter of the diode to expose it's axial leads, and the solder pads where the diode connects to the busses. Once you have the diode exposed, you can carefully cut one end at its solder pad and gently pry the lead up from its embed. After completing this (one for each side of the line where the panels are to be severed) you can cut through the conductive busses to separate the array into segments. Be careful cutting through the busses so that you sever them exactly centered on the line between the panels. This will make it easier to prepare the busses for rewiring.
In my case, I chose not to reuse the bypass diodes at the panel sever points, but to replace them with new bypass devices when rewiring the array, so simply cut through them as well - eliminating the 'excavation' step for now.
Once the array is cut into the number of panels desired, the reassembly process can commence. That's for another post.
