Foldable Solar Panel - Large version

Since I published the first version of my foldable 5V solar panel, I came across larger epoxy solar panels (at about 6USD each on eBay) which measure 150x130mm and nominally deliver 500mA at 5V each (compared to the 150mA of the small 100x69mm panels used in the initial version). Also, these larger panels result in just about an ideal frame size that still comfortably fits on all standard 20x20cm printing beds.

The OpenScad source file is essentially the same as in the smaller version, since that was already fully parametrized and configurable. In addition of having the modified dimensions for the larger solar cells, the outer panels now also have loops which allow securing the solar panel somewhere, should that be needed. Given that a single solar cell delivers 2.5W, the 3-page version already delivers an output of 7.5W (which is 2x the power of the 5-page small version), I only provide STL files for 1-page (2.5W), 2-page (5W) and 3-page (7.5W) versions.

The solar cells of the 2- and 3-page versions are usually connected in parallel to deliver 1A resp. 1.5A at 5V, which is enough to charge about any 5V USB type device. However, it is also possible to wire the cells of 3-page version in series, which results in 500mA at 15V, just the right voltage to charge 12V lead-acid batteries.

As you can see in some of the photos, I even made one such 3-page solar panel which does balanced charging of 3S-type Li-Po batteries (3x3.7V = 11.1V) for a friend who wants to recharge the batteries of his quadcopter during his 2-week canoe trip through the Everglades. For this, I bring the 3 individual 5V wire pairs into the connector box and use a standard 3x2 right angle male pin header instead of the USB female connector. One cable for balanced charging then brings each of the 3 isolated 5V wire pairs is then attached to a easily available single 5V/1A Lithium charging module that a daisy chained at the output side and fed into a standard 3S XH 4-pin balancing socket. The other cable is for USB charging and just recombines the voltages of the three cells in parallel and ends in a USB charging connector.

Update 2022-12-04: At a request of user Gringo81 I added a 4-page version. Note that I have not actually printed this 4-page version, but looking at the openscad output in the open and folded position (see newly added pictures) it seems to look okay. In order to avoid a collision with the USB box, there is only 1 centered hook on page 1. I also added the updated OpenScad source file, in case you need to fine tune some of the parameters.