Green front LED lights

General cycling advice ( NOT technical ! )
smalley
Posts: 3
Joined: 30 Sep 2008, 12:45pm

Green front LED lights

Postby smalley » 30 Sep 2008, 12:54pm

I recently bought a front and rear LED light set from Halfords assuming the front light was white. However, I found that this emitted green light !
I have not used these yet but I would like to know if these are legal and if so, how efficient are they in being seen by oncoming road users?
Many thanks.
John Smalley

User avatar
cranky
Posts: 538
Joined: 3 Jul 2008, 11:28pm
Location: Glasgow

Postby cranky » 30 Sep 2008, 1:12pm

I too have a couple of sets of these that I use on my panniers. The red rear leds are pretty good but the front green leds are pathetic. I think I'll be calling on Maplin for six white leds to replace them. I've no idea of the legality of green lights showing at the front, except that afaik you must also have a white front light.
Iain

Ridgeback Genesis Day 2
Surly Long Haul Trucker

User avatar
CJ
Posts: 2967
Joined: 15 Jan 2007, 9:55pm

Postby CJ » 30 Sep 2008, 2:16pm

The only colour of light it's illegal to show at the front is red, for obvious reasons.

But regardless of whatever other colours and types of light you have on the front of the bike, you need at least one that is approved.

In bike lights there's a three level status:

Illegal: shouldn't use them on the bike at all.

Legal: okay to use them, some are very effective lights indeed, but they don't satisfy certain technical requirements in order to be ...

Approved: need at least one front and one rear, with this extra status. Not necessarily the best performing lights, but at least the manufacturer has taken the trouble to ensure that they conform with certain technical specifications laid down by the Dept of Transport.
Chris Juden
One lady owner, never raced or jumped.

GeoffL
Posts: 1168
Joined: 28 Feb 2007, 7:47pm
Location: SE Cornwall

Postby GeoffL » 30 Sep 2008, 2:37pm

While it's not unlawful to show a steady green to the front, I do wonder about flashing green lights. Flashing green lights are unlawful on a car except for a medical practitioner on an emergency call. However, flashing blue lights are unlawful on a car except for an emergency vehicle on a "shout" but many cyclists where I live have flashing blue front lights that cause no end of confusion.

Geoff

pigman
Posts: 1677
Joined: 11 Jan 2007, 12:23pm
Location: Sheffield UK

Postby pigman » 30 Sep 2008, 2:44pm

green LEDs were the first generation led front lights. White hadnt been invented then. Very cheap to buy now and Ive put some on the kids bikes as they dont venture onto the road yet, so ok for parks/footpaths.
I presume what you bought was new "old stock" lights. Hope you bought cheap.

User avatar
Kevin K
Posts: 377
Joined: 21 Oct 2007, 1:41am
Location: East Kilbride, Glasgow

Postby Kevin K » 30 Sep 2008, 2:46pm

I bought the same set of lights from Halfords, but took them back when I discovered they were green. They exchanged them with no quibble.
Kevin

User avatar
cranky
Posts: 538
Joined: 3 Jul 2008, 11:28pm
Location: Glasgow

Postby cranky » 30 Sep 2008, 3:16pm

I bought two sets (4 lights) for a tenner and clipped them on the panniers, if they get nicked I won't cry. If they don't I'll swap out the six green leds for white. I still reckon it's a good deal :)
Iain



Ridgeback Genesis Day 2

Surly Long Haul Trucker

User avatar
yakdiver
Posts: 1157
Joined: 12 Jul 2007, 2:54pm
Location: North Baddesley Hampshire

Postby yakdiver » 30 Sep 2008, 3:29pm

4th row down
EL183 Ultrablue LED Hi- visibility Cyclelight
It was sold by Argos a a rear light scars the **** out of motorists :twisted:

User avatar
meic
Posts: 19355
Joined: 1 Feb 2007, 9:37pm
Location: Caerfyrddin (Carmarthen)

Postby meic » 30 Sep 2008, 3:41pm

I bought the EL155 from the same website. It has a green LED which is so weak that it is fit for nothing. It seemed a great idea to have a BS reflector with a built in light but in practice the light is useless.

Are LEDs really so standardised that I could just use any other LED from a bike lamp or other place to make this lamp useable?

I can recommend their EL 153 as an excellent cheap and BS approved back light.
Yma o Hyd

User avatar
cranky
Posts: 538
Joined: 3 Jul 2008, 11:28pm
Location: Glasgow

Postby cranky » 30 Sep 2008, 4:17pm

meic wrote:Are LEDs really so standardised that I could just use any other LED from a bike lamp or other place to make this lamp useable?


Ideally you'd measure the (green) led current and voltage then find a suitable replacement, in practice most 5mm leds draw around 30ma and can be dropped right in. LEDs are polarised, that is, they need to be wired in circuit 'the right way round', unlike a light bulb, so sorting out your anode from your cathode is the only tricky part (assuming you have a fine tipped soldering iron)
Iain



Ridgeback Genesis Day 2

Surly Long Haul Trucker

User avatar
meic
Posts: 19355
Joined: 1 Feb 2007, 9:37pm
Location: Caerfyrddin (Carmarthen)

Postby meic » 30 Sep 2008, 11:48pm

I measured the current and it was 14mA with a 2.08V across the LED.
This was powered by 2.54V from 2NiMH AA batteries.

I assume the LED doesnt have significant resistance, if this is so then I calculated they had put a 180 ohm resistor in series with it.

I could not get any readings across either the resistor or LED using the resistance meter.

Do I have to find an LED rated at around 14mA?
Last edited by meic on 1 Oct 2008, 7:45pm, edited 1 time in total.
Yma o Hyd

smalley
Posts: 3
Joined: 30 Sep 2008, 12:45pm

Postby smalley » 1 Oct 2008, 8:40am

Thanks for all your replies.
Looks like I should return them and ensure the front one IS white.
John Smalley

User avatar
cranky
Posts: 538
Joined: 3 Jul 2008, 11:28pm
Location: Glasgow

Postby cranky » 1 Oct 2008, 11:41am

meic wrote:I measured the current and it was 14mA with a 2.08V across the LED.
This was powered by 2.54V from 2NiMH AA batteries.

I assume the LED doesnt have significant resistance, if this is so then I calculated they had put a 180 ohm resistor in series with it.

I could not get any readings across either the resistor or LED using the resistance meter.

Do I have to find an LED rated at around !$mA?


It looks like it'll be a little trickier than that. I've just been doing some research (looking at leds) and it seems that white (and blue) leds have a higher forward voltage (~3.4v) than other colours. I think I'll take a look inside one of my Basta Comet (2 cell) lights and see what's there.
Iain



Ridgeback Genesis Day 2

Surly Long Haul Trucker

kwackers
Posts: 12565
Joined: 4 Jun 2008, 9:29pm
Location: Warrington

Postby kwackers » 1 Oct 2008, 12:33pm

cranky wrote:It looks like it'll be a little trickier than that. I've just been doing some research (looking at leds) and it seems that white (and blue) leds have a higher forward voltage (~3.4v) than other colours. I think I'll take a look inside one of my Basta Comet (2 cell) lights and see what's there.


That's the main reason to use buck/boost converters - well that and current control, oh and battery life...

A good source of cheap LED's is Sure Electronics shop on eBay. They're in China but I usually get my stuff inside a week (and sometimes after just a couple days).
They do packs of 100 15,000mcd white leds, or individual 0.5, 1, 3, 5 & 10W leds - including full colour RGB which is just the ticket for disco front lights whilst listening to one's iPod.

They also sell some pre-built converters which can be used with the lights, although for converters I've used an American company who's name currently escapes me to buy tiny (12mm) ones which will fit behind each LED.

And finally and quite usefully they also sell lenses which clip to the higher powered LED's and give a pretty good beam.

User avatar
cranky
Posts: 538
Joined: 3 Jul 2008, 11:28pm
Location: Glasgow

Postby cranky » 1 Oct 2008, 1:09pm

kwackers wrote:A good source of cheap LED's is Sure Electronics shop on eBay. They're in China but I usually get my stuff inside a week (and sometimes after just a couple days).


Thanks for that recommendation. I've seen their ad's but never dealt with them before, it's good to know they're reliable.

It's probably not worth fitting a buck/boost to these lights (unless it's really, really cheap), easier to just use them as is until a low Vf diode comes along.

Have you tried their 3W leds and did they work well ?
Iain



Ridgeback Genesis Day 2

Surly Long Haul Trucker