Twin luxeon lights.

agamlem wrote:

What regulator are you using?

It's a micrel MIC29302T, in a TO-220 package. This one is cool as it's
adjustable, and also has a shutdown pin, which I may use to shut the
thing down when the battery voltage drops below 6V. I figured that
dropping from 7.4 to 6.0V with a series regulator gives me around 80%
efficiency anyway, so the gains to be made by using a switching
regulator are only modest.

I use a pwm circuit based around a 555 timer. I thought about
getting
hi tec and using a microcontroller with an a-to-d to monitor the
battery
and give various dimming levels. But it seemed like too much hassle.


So do you use a fixed duty cycle, or some sort of feedback loop to set
the output power?

I push my vista lights a bit harder at 7.2 volts (or sometimes more)
since they do it themselves for some models. They have 6 cells in
their batteries. I run a 10 watt head and a 15 on the bars. I like
to
hit about 80-90% daylight speed of road.

Mine are usually run from 5 sub-c NiMH cells, so 6V is the go. I
reckon It's plenty bright enough, and I don't want to sacrifice bulb
life, as they're expensive.

Regards,

Suzy


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suzyj