3 years ago I built a mountainbike lightset, which was imortalised as a photo-essay here. It's been the most popular of all my photo collections, and is still regularly viewed.
But all wasn't quite so sweet in the garden. The charger wasn't quite as manly as the maker claimed, and would only half-charge the batteries. Then the cells themselves started to separate and rendered the battery pack useless with an open circuit. The last thing I'd done before it failed was to charge it up as far as I could, but then other things got in the way and it was consigned to the cupboard.
With my return to riding 3 years later and the arrival of british winter time I re-discovered the need for reasonable lighting for the journey home, so I dug it out last night. 4 of the 10 NiMH cells have died, apparently beyond recovery. The remaining 6 I charged last night, then plugged in a bunch of lights this morning. Bearing in mind there was a 40 Watt load, they kept going for 30 mins with no sign of dimming, which was a good sign.
But technology moves on, and I can't now easily get more cells to match the ones that died, so an alternative had to be found. LED lamps have come on in leaps and bounds however, with a 5W watt LED producing as much light as a good 20 watt halogen lamp. The controllers are not cheap, but they will use a range of different sized packs, all while driving lamp to max brightness. I've not bought anything *yet* but it's certainly looking more and more likely that LED is the way to go.