Lights on Auto setting - Speed sensitive?

[whitenemesis]

I've noticed my lights seem to come one sooner if I'm going faster. Then go off again when speed reduces. Does speed change the point at which the light sensor turns the headlights on?

 

[whitenemesis]

Any thoughts guys?

 

[eric242340]

Very strange. The light sensor works on light or lack of it and most certainly not on speed

 

[whitenemesis]

I realise that Eric but there does seem to be a speed influence. It wouldn't be impossible to factor in an input from the speedo to the light control as well as from the light sensor?

I take it no one else has noticed this?

 

[eric242340]

If we forget the sensor bit for a moment and look at the basics it may help. What im thinking is your battery may have a problem and the faster the rpm the higher the charging rate from the alternator, this would link the engine speed to brightness of lights bit. Does it do the same if you have your lights switched on manually? Or does it only happen when the lights come on via the sensor? The strange thing is, your car does not sound very old so a battery problem?

 

[jberks]

We can relate all sorts of things athat are unrelated. Basically, no there is no relationship, so you need to figure out whether there is in your case (and you have a fault) or more likely it just seems that way.
I believe the lights are related to the wipers (or have I imagined this) so I guess it if was raining there may be an indirect connection to speed.

 

[eric242340]

We can relate all sorts of things athat are unrelated. Basically, no there is no relationship, so you need to figure out whether there is in your case (and you have a fault) or more likely it just seems that way.
I believe the lights are related to the wipers (or have I imagined this) so I guess it if was raining there may be an indirect connection to speed.

?

 

[television]

If we forget the sensor bit for a moment and look at the basics it may help. What im thinking is your battery may have a problem and the faster the rpm the higher the charging rate from the alternator, this would link the engine speed to brightness of lights bit. Does it do the same if you have your lights switched on manually? Or does it only happen when the lights come on via the sensor? The strange thing is, your car does not sound very old so a battery problem?

Once again eric totally wrong information.

Since when do you have a car with dim lights at 30mph brighter at 60mph to the point where they blow at 9omph

The car stays at the running voltage, irrespective of the cars speed. that is what that the regulator is for, and is held in line by the battery. The speed of the engine has nothing to do with the output of the alternator since the max charge rate is achieved at very low revs.

Malcolm

 

[eric242340]

Once again eric totally wrong information.

Since when do you have a car with dim lights at 30mph brighter at 60mph to the point where they blow at 9omph

The car stays at the running voltage, irrespective of the cars speed. that is what that the regulator is for, and is held in line by the battery. The speed of the engine has nothing to do with the output of the alternator since the max charge rate is achieved at very low revs.

Malcolm

? I must be int wrong biness lad but wud seem voltage andt speed are related noo?

 

[jberks]

I have to agree with Malcolm. Crudely, engine speed and therefore alternator speed governs alternator output to a small extent. On a very tired electrical system, raising revs will make a substantial difference. However, as malcolm says once you get just above idle, you're going to get as much out of the alternator as it's going to give. 1300rpm - 6000rpm will make no difference. Any difference there is, will be compensated for by the regulator. Plus, this car clearly isn't tired.

As for my point. I believe it is very clear. The faster you go, in light sporadic rain, the more rain your screen will collect and the more you need the wipers. On sensor, as the speed picks up, they will tend to wipe more often until they are continuous. Once continuous for a few secs, I find on the 211, the lights come on automatically, irrespecutive of the light level. A sensible and clever safety feature. Sometimes you observe something but guess the wrong cause.

 

[eric242340]

Your talking sense, but I still dont see how a light sensor can relate to speed? The sensor relates to light or lack of it and speed does not change the amount of light the sensor receives

 

[jberks]

Your talking sense, but I still dont see how a light sensor can relate to speed? The sensor relates to light or lack of it and speed does not change the amount of light the sensor receives

I guess we are talking at cross purposes and saying the same thing. The speed/rain/auto light connection was simply a suggestion for why he had made the speed/light connection. I agree, speed won't affect the light sensor but it could (indirectly) affect the rain sensor and that can put on the lights.

 

[whitenemesis]

Well Team,
Going to work this morning approx 6:30, dawn breaking and it getting lighter by the minute.......
Started off from home and the lights were on (switch is kept on Auto always). First 10mls of trip was single carriage way steady 35-40mph lights had switched off due to increasing ligh levels (the sun was rising!). Reached the dual carriage way and sped up to 70-80mph after approx 30sec lights came back on..No cloud cover..sun hadn't suddenly set!!! Reached end of dual carriage way, speed dropped to 40-50mph and within 30sec lights had gone off again....
I know the lights come on after about 40sec of constant wiper action (rain or no rain and no I don't have rain sensor) and I expect that as its a requirement to use dipped headlights in rain. But this speed thing has happend time and time again whenever I push along "enthusiastically"
I am not complaining, seems a good idea to let others see me coming just suprised no one else has experienced this.

Sorry didn't want to start an argument:-| The car is running quite normally, no error codes (as confirmed by the guys from Comand.co.uk who just fitted my new Comand and ipod kit...Great job "Alfie" and Richard! )

 

[whitenemesis]

:roll: See I've killed another thread.... You guys all out there checking yer lights going on 'n off? :roll: