Check your local RV or marine store - they sell flourescents that run off 12V 
DC directly. You can get CFLs that run off 12V also - no inverter required.

Althogh inverters a getting pretty cheap these days - you can buy 300-400 
watt inverters (modified sinve wave types) for $50 or so.

LED lamps are still "new" and quite expensive. For example, I paid $29 for 
some halogen under-the0counter lights - flourescents were about the same 
price. A LED version was $100.

Same with marine/RV fixtures - too expensive.

Now, if you want to make your own, using some of the high-power LEDs 
(http://www.luxeonstar.com/), that's probably a more cost-effective solution. 
I was looking into this to replace some of the interior lights on my sailboat.

Larry


Original Message:
>
Tag changed again :-)

>> Getting 90+ l/W from an LED is easy enough nowadays. Above CFL efficiency
>> and approaching that of a straight fluorescent tube.

> Are straight fluorescent tubes the most efficient only when powered 
> directly? I have recently bought a converted ambulance for use as a 
> mobile radio shack, and
> three of the four fluorescent lights in the back (powered by inverters 
> from 12VDC) have failed. Rather than try to debug the inverters, or buy 
> new ones, I was
> going to get strips of LEDs instead, thinking they would use less power.
>
> Without knowing the inverter efficiency, are the odds in favour of the 
> LEDs using less power than inverter-fed fluorescent tubes, do you think?

eg Osram Golden Dragon plus LEDs run at about 100-110 l/W in the top flux 
bin.
More like 90 l/W is common.
I have some Nichia "Raijin" LEDs that get 130+ l/W but are onlt\y 1/6 W.

T10? fluorescents exceed 100 l/W.
They are much cheaper per Watt than LEDs at higher power levels.

I'd guess 12VDC-230VAC inverters would be in the 80%-90% range.

Price parts and decide.
LEDs have their place but need to be cheaper.

One factor in the LEDs favour is that the light can be easily shaped to suit 
the application/ Use of some 60 to 90 degree LEDs is liable to be about 
right for camper-vehicle type use. I'd expect 3 to 5 Watts to be ample all 
up !!! .
That makes a difference when comparing to eg 40 W fluro.

CFL bulbs will run happily on DC.
If you can convert to 300V or whatever they are most happy with with good 
efficincy then a low wattage CFL may be useful.


Russell



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