7 Days to Die Wiki
Some items' or groups' chance to drop changes according to the player's gamestage. Here you can see those values for any gamestage you want using the little box below. Just type the gamestage you want in the box and press the Apply!-button. The values should change immediately, if the chance is different.

Current game stage: 1

Solar Cells were first introduced in A16. They are used in Solar Banks, up to a maximum of 6 cells per bank. Solar Banks only generate current when they have cells in them.

As of now they cannot be crafted or looted, and have to be bought from Secret Stash pages of Trader NPC's. Solar Cells don't have item levels.