Now here's a thing. Batteries. When that gadget starts failing, we just assume the batteries have nearly run out, and put new ones in. The old ones either get recycled or just chucked in the bin (which we're really not supposed to do). Any idea how much power is left in them? Ever wondered?
I did, so I've just checked. I have an old coffee tin, in which we put all the "dead" batteries until we get round to taking them for recycling. So I got out my trusty multimeter and checked how much power was left in them. Bit of a shocker, really. Most new batteries (AA, AAA or C anyway) start off with 1.5 volts. What would you expect the reading for a "dead" one to be? 0.2v? 0.5v? 1v even? Well, a lot of them were about 1.2v or even 1.36v. Certainly some were down about the 0.4v level, but the vast majority still held over 1 volt. So we're only using 1/3 of the power in a lot of our rather expensive batteries, and chucking out 2/3 of it.
In the pre-digital age I think we used up a lot more of the juice. We let our torches get a bit dim; we put up with radios getting fainter and fainter. But so many of our modern gadgets simply won't work at lower than optimum voltage, so we have no choice.
I suppose one solution is only to use rechargeable batteries, but they don't actually work very well in some gadgets, as a lot of them never charge right up to 1.5v in the first place.
So how much power is being wasted, producing batteries that aren't even half-used? It's equivalent to leaving your lights on all day and night when you only need the light for 8 hours out of 24.
What I want is some sort of gadget whereby you can extract the power from part-used batteries. I don't have enough technical expertise to design such a thing, but it must be possible, surely. What about some sort of box containing an array of battery sockets of varying sizes, which can be filled up with an assortment of batteries of different sizes whose residual power would add up to produce enough power to run something analogue like a radio or a clock? Does such a thing exist?
