Lights with low heat output

Glow-worms do.

Why do torches and headlamps with LEDs have such an improved battery life when compared with those with incandescent bulbs? It is certainly more than the 50% that your figures would suggest.

It's generally because small incandescent bulbs really, really suck. They only really start to perform well at sizes of around 5W or so.

Plus - if a LED is running with a flattish battery, it produces usable light, where a bulb just goes to a useless red glow.

Also, compare the beam patterns. In many cases, the LED torch may produce more light, but over a narrower area, which uses less energy.

Unfortunately, this is an area where there is a whole lot of lying going on.

'100W' replacement spot bulbs that produce a tiny dot that's as bright as the original light, for example, and rapidly dim over days of on-time, because they overheat.

But even the makers of the most efficient LEDs - for example

It shouldn't be hard to find a small fluoroescent fitting in a caravan accessories shop, and 12-14V power supplies are readily available for running car electronics / radio equipt off the mains.

The cable between the two will need to be rated for the current at 12V and is not necessarily safer than mains if damaged, because the high current availability can lead to arcing.

Owain

Far more likely their long life if correctly driven. If energy consumption was important with traffic lights they'd turn them off overnight, etc.

Use a fluorescent fitting with a diffuser.

The message from "Dave Plowman (News)" contains these words:

In the States they installed them for energy savings. There was an article about it in New Scientist once, or at least, a side item. Apparently at the time LEDs were more expensive than they are now so they only changed the red and green. The ambers weren't on long enough to make the payback worth it.

The outcome across the whole of the union was roughly equivalent to the output of a medium sized power station IIRC.

Would the LED lights use sufficiently little energy they could be powered by small turbines, or photovoltaics, on the top?

My thinking is that with self-contained traffic lights and a en encrypted wireless networking, traffic lights could be installed and replaced without digging up the roads and laying cables, and when the water board dig up a leaky main they wouldn't need to leave a genny running outside my bedroom window at 2 a.m. for the lights.

Owain

In message , Dave Fawthrop writes

Leave one on for an hour or two and the grasp it firmly with your hand. Now try and tell me they run 'warm to the touch' after you've finished applying the bandages.

Umm, no. You can get a nasty shock off a 12v fluorescent because they usually use a step-up circuit to generate high enough voltages to get the tube to strike and run, strike voltage can be around 600v and running voltage is usually high enough to be dangerous if you touch the wrong bit.

I have always heard 1-2% for incandescents.

Not nearly 10%.

Cycle lamps that *pulse* make use of the fact that we can detect short high energy light a lot better than long dim light..

I think you should research that.

First of all there is an efficiency gain, secondly, when has any council EVER removed or switched off a traffic light, once installed, no matter how daft its timing, situation or whatever, been?

And Ill pay YOU a couple of hundred for a domestic lamp that isn't as fragile as f*ck, that can reach ANYTHING LIKE those sorts of power conversions.

You might as well tell me that arc lamps are actually 'incandecsnt' and use those as a starting point.

Or do you mean LEDs.

This does not make it actually correct.

Only if the flicker is actually perceptible. If they don't flicker, then they are just as bright - or perhaps less so for LED physics reasons

I've got an RO80 one lighting this keyboard. It's in a metal fitting. Which is only warm to the touch - you could leave your hand on it all day. The previous filament lamp made the housing too hot to touch.

Doesn't need research. The reason is reduced maintenance through longer life. The energy saving is tiny in comparison to that.

Perhaps they would if they were really interested in saving energy. But there isn't a meter on each set of lights, you know, so they simply don't see any benefit of the reduced power consumption. However, they do with maintenance costs.

In message , "Dave Plowman (News)" writes

Right, now touch the glass.

Yes. Unfortunately, the first generation turned out to be very short lived before the LEDs died.

Traffic lights are not normally on a metered supply in this country. This was an important reason in the US, where they are more often metered, and where they use inefficient mains bulbs. UK traffic lights have used LV halogen bulbs for decades, which are much more efficient than mains signal bulbs in the first place.