LED shine a light!

Sounds like the classic signs of a dodgy earth. My 16H earth has an earth tag rivetted to the headlight shell but the rivet was loose and light blinked on and off. I drilled it out and put a new pop rivet in and now more problems yet... I suspect LED might be more sensitive to bad connections owing to low current draw. or of course a bad bulb...I got LEDs from Classic Dynamo & Regulator Conversions for tail, speed and pilot. They seem to be robust.

This sounds as if they are not very robust - not enough to survive the legendary vibrations of a big twin! Another thing to remember about LEDs is that they are quite voltage sensitive. E.g. a 12 volt LED wants 12 volts! Not 13 or 13.5, which is the normal running voltage of a 12 volt battery. If your battery reads 12 or even 12.5 volts when not being charged then it is flat or nearly dead! The higher voltage, and any hint of AC, will shorten their lives considerably. You can (or could ) buy a 12V regulator from eBay which give a constant output of 12 volts when the input is 13 - 14 or more. Mine cost £3.85 each and they are for my motorhome, not the bikes which are all 6V. I asked Paul Goff whether he'd had any trouble with over-voltage on LEDs and he said not. To be fair he's bound to say that!

The LED bulbs from Classic Dynamo and Regulator Conversionsseem remarkably robust - and not too voltage sensitive. Their BPF bulbs are for any voltage between 6 and 24. I use them in 6 and 12 volt applications and they are fine - and such a tiny current draw. Great for 40 watt dynamos! The speedo bulbs are fairly directional so don't illuminate quite as well as normal incandescent ones. Perfectly good enough though.

That sounds more useful Gordon. The world is changing over to LEDs so I feel sorry for anyone with an investment or business with the so-called "Low-Energy" bulbs because they have effectively been superceded. They even make a fitment to replace a 230V 2D fluorescent. It makes sense in a domestic situation for the same reason as with bikes or cars - less amps. That also means less strain on old wiring, whether it's 6, 12 or 230 Volts. Incidentally, the UK still runs on a nominal 240 Volts mains as we saw no reason to change! The EU regs say that the voltage should be 230V +/- 10% so our mains can be from 207V to 253V. Mine regularly runs at 247V off-peak.

Previously Gordon Johnston wrote:

The LED bulbs from Classic Dynamo and Regulator Conversionsseem remarkably robust - and not too voltage sensitive. Their BPF bulbs are for any voltage between 6 and 24. I use them in 6 and 12 volt applications and they are fine - and such a tiny current draw. Great for 40 watt dynamos! The speedo bulbs are fairly directional so don't illuminate quite as well as normal incandescent ones. Perfectly good enough though.

I agree with Gordon, the LEDs I bought from Classic Dynamo and Regulator Conversions are robust and seem very 'voltage-tolerant'. They also seem to be able to supply a wider range of products than some other suppliers. My only advice is that the LEDs must be the same colour as the lens they are to shine through, e.g. red led for red lens, white led for clear lens etc. otherwise a lot of light is 'lost' (I think this is to do with the light wavelength etc.).

Regarding Mike's first enquiry; are not most LED lights negatively earhed? If your bike is positive earth and you put the LED into the bulb holder the bulb probably will not light. Are you providing an earth path while touching the bulb holder? Is the LED then going out as the positive [earth lead] is attached in the wrong direction of current travel in the LED - LEDS normally only work with current flowing in one direction.

I have bought LEDs for my Commando but have been wondering about this - if I connect the positive to the the "negative" terminal and vice versa will the LED work then?

Roger

Previously roger_johnson wrote:

Regarding Mike's first enquiry; are not most LED lights negatively earhed? If your bike is positive earth and you put the LED into the bulb holder the bulb probably will not light. Are you providing an earth path while touching the bulb holder? Is the LED then going out as the positive [earth lead] is attached in the wrong direction of current travel in the LED - LEDS normally only work with current flowing in one direction.

I have bought LEDs for my Commando but have been wondering about this - if I connect the positive to the the "negative" terminal and vice versa will the LED work then?

Roger

See my previous post. The headlight bulbs are available in positive or negative earth, both do 6 or 12 volts. The tail bulbs are not polarity sensitive, i.e.will work with positive or negative earth. It's quite fascinating to switch on high beam headlights and see the ammeter show only 1 amp discharge.

Ditto Dynamo Regulator - all my bikes are now sporting LED's including dipping headlights. They are at the forefront of development of this technology rather than merely a retailer.

Previously roger_johnson wrote:

Regarding Mike's first enquiry; are not most LED lights negatively earhed? If your bike is positive earth and you put the LED into the bulb holder the bulb probably will not light. Are you providing an earth path while touching the bulb holder? Is the LED then going out as the positive [earth lead] is attached in the wrong direction of current travel in the LED - LEDS normally only work with current flowing in one direction.

I have bought LEDs for my Commando but have been wondering about this - if I connect the positive to the the "negative" terminal and vice versa will the LED work then?

Roger

If a full wave rectifier is fitted between the power source (either + or - earth) then the LED will receive the'correct ' polarity automatically. Such rectifiers can be purchased for a few pence or built-in to the LED at virtually no cost. Hence the modern 'plug and play' (or 'plug and pray' functionality).

HtH

Oddly enough, from my experience with replacing incandescent bulbs with LEDs on my motorhome, quite a few multiple LED fitments are NOT polarity concious. These are usually the flat disc-shaped type which have circuitry on the back. I buy mine throug eBayfrom China as they are cheaper. E.g. Some are99p each including postage!!

Mark is correct in that you generally need an LED the same colour as the lens it shines through. It's due to the properties of light not being quite what we think they are. We (might?) assume that if you put a red (green, blue oryellow etc) lens in front of a 'white' light it changes the colour of the light to that of the lens. Nope!A lens acts as a light filter so a red lens will only allow the red component of the light source through - blocking all other colours. Most 'white' LEDs have no red component - remember that our sunlight has a wide range of colours in its spectrum so any colour lens will filter its colourthrough. LEDs tend to be at the blue end of the spectrum, although I haven't yet tested the 'warm' white' versions through a red lens. What we regard as 'true' colours are simply that way because of the colour of our sun. Easily seen by looking at colours under a yellow sodium lamp - not reflected as 'true' colours. We see colours according to the colour of the light source.