- Sun Dec 30, 2012 3:22 pm
#21079
Norm, the H4, or indeed any other tungsten or halogen headlight lamp, (i.e bulb or globe) has miniture filaments which are set at precise focal points (pre-focussed) in the headlight units reflector and lens to provide the correct beam pattern, cut-offs and dip/main beam options.
The problem with the H4, H7, H1 OR H3 type LED lamps is that there is no single focal point - the LEDS are arranged along the length of the lamp and emit light to very many points of the reflector and through the lens. PeteF, you are correct that the law states that is must be a white light, but also the MOT test will check beam pattern and operation of both high and low beams. The LED H type lamps are cool white (4500K approx) by the way.
As Bertie says the reason why these LED lamps are illegal is that, not only are they not CE marked but they would fail miserbly the beam pattern test. They also would not offer a discernable main and dip beam performance.
This is due the the arrangement of LEDS on the lamp, there is no way of changing this until someone makes a single chip high output LED H4 or H7 type lamp - and I haven't yet seen one of these.
On holiday in Turkey last year I did see a clone CG125 with a bright dazzling white headlamp - this was an H4 type LED. The glare was hideous and there was no beam as such. Riding with this lamp would present a major hazard to oneself and other road users.
The benfits of LED - long service life and low current consumption are well documented but for the headlight application there is currently no option, at least in the retrofit market.
My Electra XS has LED front position lamp, instrument lamps and warning panal lamps. I have spent a considerable sum on rear stop tail (red and white) LED lamps but not found a 100% satisfactory product as yet. Therefore I run a Halfords HD rear 380/1157 lamp, and as a headlight the Philips Moto-vision, which is excellent.
I will keep experimenting with the rear lamp and may make something up myself using 12v LED warm white and red LED strips, but I fear that you will be very disappointed with the LED H4 lamps Norm.