Forum

[ogri]

Hi there. I purchased on ebay a couple of LED lights:
Waterproof 12V 30W CREE U2 LED Laser Light Motorcycle Car Headlamp Silver/Black

They were good value, about £20 all-in. I've connected in with the very tiny lights above the headlight however the ammeter swings hugely into the negative side and even going along at a good speed it never gets into the + side. I always thought LEDs had a very low electrical consumption, however it looks like I'm wrong on this one!

[PeteF]

The clue is in that 30w in the description. Twice that is 60w which is a hell of a lot for the puny output of the usual RE alternator.

[ogri]

Just back from a short break with no internet - pure bliss!!

Thanks Pete for your reply. Yes, looking at it now it's fairly obvious, although at the time I was thinking that 30W would be the equivalent output of, say, a halogen-type bulb, whereas the actual LED consumption would be tiny, a bit like the way they advertise new LED replacements for house lamps.

Does anyone know the output of the standard alternator or if it's possible to increase this? I quite like the look of these new lamps, and the added security they offer, so if possible I'd like to keep them.

Any help much appreciated.

[Count Johnny]

I'm not an electronics expert - even slightly - but there's something weird going on there.



LED bulbs DO draw the thick end of nothing, so I can't understand why you're seeing this much current draw.



If you're determined to uprate your alternator (I did, but for entirely different reasons) our hosts sell uprated stators and rotors which are supposed to produce 120 Watts.



But, as I said, there's something not right here and it's not terribly clear exactly what you've installed. Perhaps a better description and/or a picture?



By the way, EBay headlight bulbs don't work - in that they are incapable of focussing light on a reflector, so merely fill a headlamp shell with lovely white light, while not even slightly lighting the road.

[PeteF]

Just looked them up on Ebay.
Quote:
Light power 30watts, actual power 9-12 watts.
So that's something like 20 watts for the pair which is still quite a significant load.

[ogri]

Thanks men.

Pete, at that rate the two lamps would be less than the standard headlamp bulb, no?

I have these wired to come on with the small pilot lights so presumably the load is just too much for the output. Thinking of it now, with just the pilot lights on the ammeter is only slightly into the + and with the headlight it goes a tad further, so I suppose I should've thought a bit more before hitting the 'buy' button! Shame as they look really smart.

[PeteF]

I don't know what bike you have but the later models have the headlights fed AC from half the alternator while everything else is fed DC from the other half. You can't run the LEDs from the AC and as you have it at the moment you are running side lights, ignition and the LEDs from about half the alternator output. It's obviously not enough. I know when I use the indicators I always get a discharge unless I have a fair few revs on. Ditto the brake light or horn.

[PeteF]

Mmmm, can't do pink text from the tablet!