Originally Posted by barnakiel
That's correct, the 220/110V version requires an inverter
(but the 220/110V version is better than twice the LED's efficiency too).
But the 12V from Steca is a 12 DC, no loss, and still way more lumen/Watt efficient (I do not mean better, because there are all other factors as mentioned by Noelex).
(Yes, yes, I know it all belongs to a separate thread and I might be distracting - apologies to all!)
The 46 to 50 luments per watt figure quoted for the CFL is the total for the output of the bulb over 360 degrees. When you mount this in a light fitting some of the light will be emitted behind the globe. This is especially true of boat fittings where height restrictions prevent the filament being mounted vertically. Even assuming the best case of a vertically mounted filament in a luminare that projects well below the ceiling heights, no reflector is perfect, particularly, with a bulky CFL sitting in light path.
If you want to compare apples with apples the lumen per watt figure for the bare emitter (“Globe” only) for the more recent LED’s are
Cree Q5 85 lumens per watt
Cree XP-G 111 lumens per watt
Cree have just announced they have achieved 208 lumens per watt, so we should be seeing further improvement in the near future.
Because they emit the light over 180 degrees instead of 360 degrees the achieved light output, in a fitting, will be higher for a LED than for a CFL with the same lumen per watt figure.
The major problem of CFL on boat however is not the efficiency , but the availability of only relatively high wattages.
For the wattage of a single
CFL I can, and indeed I am at this moment illuminating my boat with LED, reading light for myself and my wife, a couple of lights for food
preparation a light over the nav table an anchor
light and another LED’s providing general illumination.
I would need 2 or 3 CFL to duplicate this illumination, with a corresponding increase in power consumption
CFL are ideal for producing large amounts of light over a broad area when they can be mounted high with a luminare that takes advantage of their 360 degree light production. These conditions do not exist on an energy conscience yacht with low ceilings.
I suspect these LED offerings from Phillips are using out of date LED's , but to claim they are provide less efficient illumination than a CFL by comparing the output of the bare CFL globe against the total LED fitting is flawed.
Sorry for the distraction