This article was published in 1999, in Newsletter 22.

If you have dynamo lights that keep blowing their bulbs, consider fitting a regulator to the circuit. This does two things:

  • it prolongs the life of your bulbs (especially if you occasionally whiz down hills at a fairly high speed)
  • saves bulb two from overload when bulb one blows. When a front light bulb fails, the back lamp usually lasts only a few hundred yards, shining rather brightly, before it follows

A regulator is also worth while if you fit a halogen front light bulb (a good idea, as these are brighter than the ordinary kind). This is because halogen bulbs are very sensitive to overload (because they run much hotter) and quite expensive to replace. Note that some models of generator, and some lights, have a regulator built in.

Howes Cycles sells a Reflectalite regulator for £4.99. Campaign and CTC members are entitled to 10% discount. You get a little plastic-encapsulated thing with a push-on connector and two short wires (40 mm or so) coming out of it. In the same packet is a selection of crimp-on connectors. The two I’ve fitted also needed a cable tie or bit of plastic tape to stop the regulator dangling loose on its wires. It fitted neatly on a spare bit of the generator bracket in each case. They really do work. The only complicated thing about wiring in a typical regulator is getting its two wires the right way round – one to the generator, the other to the cycle frame.

Mark Irving