On Thu, 20 Jun 2013 02:12:21 +0100, "Arfa Daily"
wrote:


If you really *don't* want to
use a single battery solution, then the other simple way to do it, given
that you've now told us that the nav lights are LEDs with an appropriate
internal resistor for 12 volt operation, is to hang the lights across the
full 48 volts, but quadruple the series resistor. Or if you can't easily get
to the resistor to replace it, add an external one of three times the value
in series with each light.

Arfa

Interesting idea. I hadn't thought of that. You are correct that I
can't easily get to the internal resistors, but adding external
resistors would be easy enough. However, If I add the appropriate
external resistors to drop the additional 36 volts, I will be creating
a lot of wasted heat. The nav light resistors would be dissipating 2
watts each while the anchor light R would be dissipating over 6 watts.
The spot light R would be dissipating 62 watts! I think I'll stick
with the (switching type) dc-dc converter. Your comments about added
complexity are well taken, though.

Pat