BoatBanter.com - View Single Post - Efficiency of lighting

On 30 Jul 2004 09:31:30 -0700, (Rob) wrote:

Is DC lighting more efficient than AC??? The reason I ask is as a
result of looking at navigation lamp specs. All the lamps output 40
candelas. However, the 12v and 24v lamps are only 25 watts, whilst
the 110v lamp is 47W and 240v lamp is 53W. All nav lights have the
same lenses.

My inference is that you get more candelas for your watts at low DC
voltage.

Any scientific explanation out there???

FOr heating a filament, RMS watts are exactly the same as DC watts.
But, if you make a filament that will last 1000 hours at 150 V on
average, it will last much longer at 100 V, but the candelas/watt will
be lower. So, it could be the projected life of the AC lamps is
longer.

However, the DC nav-lite bulbs are quite long-lived.

Rodney Myrvaagnes NYC J36 Gjo/a

Was George B. Selden the true Inventor of the submarine patent?