We may receive a commission on purchases made from links. Imagine having the power of the sun in the palm of your hand. In this age of tech moving toward sustainable energy, that's increasingly ...

This is a simple NiCd battery charger powered by solar cells. A solar cell panel or an array of solar cells can charge a battery at more than 80 % efficiency provided the available voltage exceeds the ...

The sun is finally making a comeback, which means festivals, garden parties and – most thrillingly of all – the prospect of harvesting free electricity from the sky using one of the best portable ...