Closing the cover we keep the battery wires out. Now a 18650 clip holder is needed… mine is travelling from China to Italy together with his nine mates. So you will find here an update in a month or a bit more. For now let’s use a rubber band (from a bicycle tire) to keep wires connected and let’s attach battery with a piece of double face tape.

Maybe that pcb will reset when you take off or disconnect the battery. In that case you have to soft-power it again, notice that DC input wires are accessible from the narrow slot between solar cells and container, try to keep an easy accessibility to them, otherwise you have to open the case. Also remember to mark the wires so to know which one is positive and which is negative. Yes I know, much better to use red and black wires... :-P