skoobidude

As well as the swedish marques in this country I've noticed that new 3-series coupes now have lights on during the day. Is this a coincidence or a new safety thing?

Nick

Snazy

I leave mine switched on too. HID's aint gonna die anytime soon, and they turn off with the ignition.

Daytime running lights are becoming a more common feature though, with Audi's using LED based ones etc.

Safety is the name of the game.

pippyrips

I leave the light controls on my RS4 on auto - they come on in what i think is still relatively good light conditions i.e. a bit too soon in my opinion so i suspose it could appear like it had DTRLs

lestippp

Drive with mine on virtually all the time. I want people to have the best chance of seeing me, even in bright sunshine!

It definatley is all about safety, same reason that Volvo do it as standard and why bikers generally have them on, with their lower visual profile.

Matteeboy

Leave mine on auto too - quite a nice "trick" when driving through a dark tunnel!

Anderooo

Have to agree, tend to have at least side lights on all the time. And anytime i go near a motorway always go to full headlights. Fed up of seeing idiots on a misty morning with no lights on just because it isn't night time anymore. Should be law in this country to have lights always on, its not about you seeing the road but other people seeing you.

stuh1981

Went to France with my Dad a few years back. He took his Volvo, which had its lights constantly on.

The whole trip motorists were flashing there lights back at him. It was getting really annoying

corradoboy

I use sidelights on dull days, used to keep them on all the time in the Scoob to help with the dodgy battery/alternator problem. A mate who has a Volvo says his headlight bulbs last about 4 months, and cost him £18 a time to replace.

Dracoro

Sidelights ok, but headlights are a no-no unless visibility is poor. esp the xenon/hid that bounce and blind you. ann audi tt behind you on motorway is ok but if it's in a different lane then they blind you for some reason, poor design.

MattW

I have DRL's on my S3. Only the front lights are lit permanently. IIRC it will be EU law in about 2010, however some EU countries have the law already.

mojo monkey

its pretty common in abroad for people to drive with lights on..i drive through czech republic quite often..and its the law that you have to drive with your lights on in daytime..even the car hire companies there will tell you too drive with lights on...

HankScorpio

I have mine on all the time as I find the dash quite dark especially when going in and out of shadows. (A3)

DCR59

I read somewhere too that they were to be law in a couple of years.
So some manufacturers are lauching new models with them already fitted. My mates just bought an Audi A5 and it has a row of LED's at the base of the headlights for this reason.

skoobidude

Dash lights are on all the time in my car (350z) as they are set deep within their instrument binnacles.
However, I only put my lights on during poor visability.

I'm told so much at work about saving energy. "Last one to leave switch lights out/printers off etc". So I find it daft to drive with "lights" on when visibility is ok!

Nick

paulwrxboro

but it costs nothing to have your lites on your car and could save your life ,silly not to realy

i allways have mine on ,and seems to stop ppl hogging the fast lane dont know why

gar

No lights during the day usually, unless I'm doing 140+

HankScorpio

Assuming 2 * 55W bulbs and 10% efficiency in converting the fuel's energy to crankshaft torque and thence to electrical power;

>> Petrol_LCV=32e6; % Petrol Lower Calorific Value (Joules per litre)
>> Lamp_Power=110; % Electrical Power consumed by lights
>> nu_total=0.1; % Overall efficiency between fuel and lamp
>> fuel_volume_flow_rate=Lamp_Power/(nu_total*Petrol_LCV);
>> Litres_per_hour=fuel_volume_flow_rate*3600

Litres_per_hour =

0.1238


Not my calc, there is a tree hugger campaign to stop manufacturers selling cars with drl because of the eco concerns.

MattW

The assumption is incorrect, they are separate 21w bulbs on the A3 as the main and dipped beam are HIDs

jjones

that was a reply to a "it costs you nothing", so the assumption is correct, it does cost you more to use your lights, no matter if they are 21w or 55w.

girl-in-a-scoob

Always have my side lights on, guess it comes from owning the bike and the visibility idea

richs2891

Always have the side lights in, They turn off with the ignition so don't have to think ! Just have to keep checking the number plate bulbs as they have a habit of blowing !

Richard

Anderooo

So either be seen or save the planet? Personally I would turn all my lights on and run the damn tree huggers over, and then go back and run them over again.

I will continue to drive with my lights, as it makes sure I can be seen. Perhaps you have to live where the miserable old sods randomly pull out of junctions when you are 10ft away and do 25mph to appreciate it.

Snazy

I thought the IAD recommended driving with side lights on at all times minimum.
Apparently a source of light helps to see if a vehicle is in motion, and judge speed too.

I always have, and always will.
We drive band F/G cars for god sakes..... bit two faced not to use side lights to "save the planet" eh.

Brendan Hughes

I don't understand any of this. I thought the battery was charged by the alternator, which is driven by engine speed, via a belt. In what car does the alternator (and therefore the engine) speed up in order to charge the battery? None surely? The charging is a by-product of your engine speed and thus fuel consumption, there is no time when the engine revs itself simply to charge the battery. Correct me if I'm wrong, but I think the above argument is horsesh!t.

To me, the only reason to drive with your lights off is if you have a crap battery/ old car, and the heater and wipers are also draining it (driving home on a rainy winter night). I thought that's not true for any car built in the 90s onwards.

As said, the EU are planning to make it law sooner or later, its one of the four modifications they plan to bring in as a road safety measure. The others being blind-spot mirrors for trucks, and something else...

Brendan Hughes

Hmm, it seems the Dutch don't agree with me. Here's the research on DRL:

http://www.swov.nl/rapport/Factsheets/FS_DRL.pdf

jjones

damn and there was me thinking you have found some source of free energy

TopBanana

Your understanding is incorrect.

When you draw current from the alternator it has a braking effect, so you need to use more fuel to maintain the same speed. In fact, some of the hybrids actually use big effing alternators as brakes, recycling some of the kinetic energy. Clever stuff really.

Brendan Hughes

Thanks TB. I'm still not sure of it (surely alternator is always producing current when rotating, not just "to order") but it's sounding more feasible. Is the braking effect something to do with electromagnetism? My knowledge of physics is hazy at best.

I get the message that I'm thinking of an effect from the engine towards the alternator, but you're saying the chain of events starts at the alternator and goes back to braking the engine...

Anyway, if this has been decided (and even used) by mechanics, that's fine, I bow to superior knowledge - I just didn't like the idea that it had been produced by Hank's tree-hugger group as a silly argument

johnnyroper

the alternator will only put out the current that is required to keep battery charged and run electrics,it is controled by the electronics on the back of it diodes and stuff.
for instance if you have to jump start because of flat battery you can hear the extra load on alternator.
the same as if you put all electrics on when engine is idling.

HankScorpio

Just for clarity - not *my* tree hugger group! I'm aware they exist but I'm in no way affiliated with them - in the same way I'm aware of people who have sex with animals