Free electricity (-ish)
This is my experimental recycled solar panel made from old garden night lights. I got 9 lights from nice people on Freegle (Freecycle), but unfortunately one solar cell was broken when I tried getting it out of the casing. I still have 8 which generate a decent 10 volts in bright light, more than enough to trickle charge the 6-volt wet cell you can see in the photo. The sun had gone in and I was only getting 4.05 volts at this point, but not bad for a first attempt. I reckon that an array of 12 cells x 3 (36 in total) would give a usable 6 volts charging supply for emergency lighting.