Have a Kobo e-reader and want to be environmentally friendly at the same time? A hack on Instructables will allow you to do just that by charging the e-reader with solar panels instead. So in a sense, you may never need to charge the device again.
The hack, devised by Instructables user "Flapke," uses solar panels along with a Schottky diode. From there, you have to take the e-reader apart and cutting out a hole for the panels to fit.
When adding the panels, Flapke notes that you'll want to make sure you line them up in parallel (negative to positive and so forth) and wire them together. To make sure the solar cells stay put, use some double-backed tape. Then carefully wire the panels to the battery with the Schottky diode (again keeping note of positive to negative), tidy away any stray wires.
This hack sounds useful, but you'll probably need to give your Kobo a fair bit of sun exposure to really see the benefits. Flapke points out that due to the uneven charging curves of lithium-ion battery-powered e-readers (they'll charge quickly to a point, but then charge more slowly until full), the current of the solar panels cannot exceed 10% of the full capacity. If capacity is full, make sure you don't over-charge the e-reader by keeping it out full sunlight, unless you want the device to stop working.
If you want to give the solar charging hack a go, check out all the steps on the Instructables page.