It would be nice to be able to charge your batteries charge without using any conventional electrical chargers. Well, Knut Karlsen did just that. His homemade solar batteries are made out of normal rechargeable batteries, with built-in solar cells. All you need to do is to leave the batteries under the sun, and they will slowly regain energy.

What you need for this DIY project is:

  • Some rechargeable batteries
  • Flexible solar cells

Here are the basic steps:

  1. Glue the photovoltaic cells onto the batteries.
  2. Then, with the use of a conductive silver pen, connect some flat wires from the battery, to the PV cell.

It’s as simple as that. You have now got homemade solar batteries that will charge (albeit slowly) when you leave them under sunlight. It is not ideal, but it is a convenient way of having fully charged batteries at your disposal. This is perfect for camping trips. There is no need to bring cumbersome chargers.

This is just a prototype.  There are some flaws in the design, as stated in the comments on his blog. One stated that you don’t need to cover the battery because not every area will be exposed to the sun. What you can do is to wrap three-fourths of the battery. Or, if you do like to wrap it, then you can place a mirror behind the battery. In any case, newer solar cells can charge even in shade.

With regards to the battery life, what you can do is create some sort of rechargeable battery skin, just like the commercially available battery adapters. That way you can reuse the solar cells once the battery stops charging. There are some concerns about the batteries discharging themselves because there are no blocking diodes to stop the charge from flowing back to the solar cells.

Plus, I was told as a child not to leave batteries under the sun, or they will explode. The inventor didn’t provide data with regards to the efficiency or safety of his homemade solar batteries. In any case, these are just prototypes, and we will write more about this subject once more information about this is made available.

A homemade solar battery is a good idea to be worked on. Maybe someone will come up with an even more well-designed concept which will answer all the concerns regarding Knut Karlsen’s prototype. We have to admire the guy for coming up with such a good idea with his SunCat batteries.

For photos of his batteries, please visit his blog.