Converting a 12V LED bulb to 6V

Kiel the Canuck /

When you have a 6V Motobecane, lighting options can be a little limited if you're keeping it original. While I will some day make a nicer panel-style LED insert, I had a 12V "tower" style LED bulb to play with.

As it is, there was no way I could get that LED to work well. The forward voltage of each LED added up and left it barely visible. With a bit of work, I could have tried taking the whole tower apart and adjusting the current limit resistors, but that was a pain to take apart.

So, my next idea was a voltage doubler - a circuit designed to take AC voltages, and provide approximately double that in DC - not a bad solution for a DC light!.

But where to put it? The BA15 shell is pretty big, and the light already had a protection diode wired in, so with two more capacitors and another diode, I had the circuit assembled.

The shell had to be isolated from the board (otherwise it would short out the doubler) so I left a gap that was then insulated with electrical tape and physically secured using hot melt glue.

It's not pretty, but it's just about as bright as it was when tested with 12V. Hopefully I'll have some night time photos to show it off later on.

Edited 1 time(s). Last edit at 03/26/13 08:42PM by Kiel Lydestad.

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