Today I received the
Adjustable Step Down Regulators, I'll only need one for this project but it's such a useful device I bought a spare, they can take up to 30v input so fine for 24-26v batteries but unfortunately no good for 36v battery setups. But the nice thing about using one of those DC-DC converters for your LED setup is you don't have to use your bike battery, you can easily use a 6 or 8 cell battery pack instead without having to re-calibrate the voltage going to the LEDs as the DC-DC converter outputs the same voltage for the LEDs no matter what the input - so long as it's higher than the voltage used for the LEDs plus 1.3v, so powering 3.4v LEDs you need a minium of 4.7v input.
Another good reason (besides simpler wiring for the LEDs) for using this DC-DC converter is that your lights will remain the same brightness when your bike's battery runs low, I ran mine completely flat recently to help cycle the individual cells inside (battery's running better now), my prototype front light setup remained bright even when the battery could hardly power the motor.
The small black box I'm using to house the switch and the DC-DC unit is from Maplins, part number
N78BQ, it's not rated as waterproof but running it under the tap didn't show any leaks, I had to completely submerge it in water and shake/tap it before a couple of drops got in - so I'd say it will be fine for rainy conditions with a little extra care when making it. It will be mounted on the handlebars with the mounting that came off the reflector as my bike already has a reflector mount that goes on the forks.
The switch is also from Maplins, it's a
Sub-Min Toggle E as I had it already but the A type is all that's needed, I'll be getting a
waterproof cover for it when I can next get over to the store.
