Derelict Sunday - Battery Pack

This is a rechargeable battery pack which I made up about 30 years ago, to power an ophthalmoscope for use in my practice as an eye surgeon. I recall that it cost me about £20 for the parts, whereas buying a professionally-made pack from the manufacturers of the ophthalmoscope would have cost somewhere near £100. It gave me many years of thoroughly reliable service until the batteries decided that they couldn't hold their charge any more. By then I was busier and less poor so I bought a "proper" one!

For a case I used a plastic box in which surgical sutures were supplied, and wrapped it in leathercloth for protection - as you can see from its derelict state this wasn't entirely successful! The lid was hinged to allow for service access. The other bits came from Maplin. The 3-position slide switch allowed either 1,2 or no resistors to be switched in so that I could vary the brightness of the ophthalmoscope light. The red push switch was the on-off switch; the socket in the centre was the output and the black socket on one corner was for charging. As NiCad cells can put out a fairly high current I thought it wise to include a fuse, although that never blew.

I did, of course, build the charger too.

I hadn't realised that I still possessed it until I was sorting through my junk box last weekend. I kept it for blipping - but now I'll remove the batteries for recycling and throw away the rest, otherwise my better half will want to know why it's still lying around! :)

Many thanks to rainie for hosting DS this month.