by ericmark »
Thu Jan 25, 2018 12:31 am
I have bought home bargains and lidi LED and CFL lamps after the expensive Philips simply did not last, OK Philips CFL not LED but taught me an expensive lesson, cheap ones are better.
I have had some extremely cheap 0.58W 12 volt MR16 replacement LED's fail, but not one of the more expensive types, typical 3 to £10 have failed. 4 LED pods in bedroom now had LED GU10's fitted for over 2 years, the bathroom has 4 x 3W 12 volt lamps well over a year old, kitchen a LED tube around 2 years old, and dinning room 6 x 3W LED candle bulbs and living room 10 x 5W LED globe bulbs non have failed.
There are a few ways to limit the current in LED lamps, the best is considered to be pulse width modulated drivers and with these you often get a voltage range, my drive LED lamp is rated 90 to 250 volt and is clearly a PWM driver in the lamp, as likely is the tube in the kitchen. However these do not dim, so for the typical bulb a very crude capacitor is used to limit current, plus a bleed resistor as without the bleed resistor the lamps will likely glow dim due to capacitive and inductive currents in the supply cables, with 12 volt versions often a resistor is used.
With PWM control we are looking at around 100 lumen per watt, but with resistors and capacitors more like 75 lumen per watt, for caravans and boats with a DC supply you need an expensive lamp rated 10 to 30 volt, and since a fluorescent tube is around 92 lumen per watt with an electronic HF ballast the LED has to be at least 100 lumen per watt to be worth using. However most simple bulbs are between 60 and 80 lumen per watt the larger the wattage the better the lumen per watt as the bleed resistor is what stops it reaching 100 lumen per watt.
So you are very unlucky, in the main the GU10 LED is very good, they do lose some output over time but in general are very good. The problem is as the wattage goes up, the area seems to be reduced, so 3W is about the best size, although you can get 7W unless aimed at a white reflective surface much of the light is lost.
In mothers house I have some 10 and 12 watt ba22d bulbs, but in real terms the light output is not as good as the original 100W tungsten so down stairs I have doubled up on the lamps, and in the bedroom the lighting is really not good enough to read with, but ample for all other things.
At home main bedroom has one 11W CFL and 4 x 3W GU10's two on ceiling and two on the wall either side of the bed.