On Tuesday, 23 October 2012 10:24:02 UTC+1, wrote:
On Tuesday, 23 October 2012 06:58:59 UTC+1, Chris J Dixon wrote:

swimmydeepo wrote:



I've just installed 4 led down-lighters in a small bathroom...very happy so far.



My first advice? Go for low voltage ones - watt per watt 12v led gives more light (more efficient) and a more pleasant white than the high voltage bulbs



Would you care to explain that a bit more? Aren't the actual LEDs

identical, it is just the production of a suitable voltage for

them that differs between LV and mains lamps. Do you mean that

this conversion loss lowers efficiency?



I think swimmydeepo's statement comes about from the lower voltage LEDs ability to share the LED driver. Having one driver for lots of low voltage LEDs is probably more efficient than having one driver per LED.



Running an LED at a lower current is more efficient if you can arrange that. The graph of light output versus current is a curve which is steeper at lower currents. Running several LEDs at low current is more efficient than running a single LED at high current.



dan.

not really...the driver might play a part too but I'm talking of simple comparison side by side between 2 identical 3 watt bulbs (same manufacturer - CREE), the only difference being that one is a MR16 low voltage and the other is a GU10 high voltage - the difference in the quality and the quantity of light emitted by the two is quite noticeable...I have compared other types and makes and the only constant results is that low voltage offer more light and a more pleasant white. Then, we must consider that the low voltage driver takes a bit away from that efficiency but it is very negligible.