Dipped Headlights.

That's a joke presumably ? Britain was an EFTA member up until joining the 'Common Market' as it was then.

There WAS a referendum about joing the Common Market but it has changed beyond recognition since that time.

Graham

Which are still the ones that nearly everyone complains about.

I'll have to try doing a one-handed U-turn!

But to piss on my own post, as it were, is it not possible that the output of the alternator exceeds the needs of the battery and if not used for additional illumination, would be wasted?

No! The power needed to drive the alternator will be pretty much proportional to the electrical load.

There can be no argument that running with any sort of additional lighting (or other electrical load) will increase fuel consumption. Whether the small extra cost and pollution this will cause is justified by an anticipated increase in safety is another question of course.

Chris

I'm trying to find out what your reasons are beyond "because I say so".

Not quite right, Graham.

Ted Heath took us in without a referendum.

It was a Labour government in 1975 that gave us a referendum asking us if we wished to stay in, and we voted yes, by a fairly small margin IIRC.

Best wishes all, Dave.

I'm a bit rusty on alternator theory. Please correct me if any of the following are wrong. The power is mostly used to run the engine, and turning the alternator is something of a by-product. Does the alternator need to run faster when you switch on the lights?

I think I'm missing something in the next bit...

Meaning that use of additional lighting has no effect on fuel consumption?

Meaning that there is additional fuel consumption?

It's not specifically alternator theory, just very basic science.

The power needed to turn the alternator is not any sort of by-product. (Neither is the power needed to turn the power steering pump, water pump, or air conditioning compressor.) If that was the case you could argue that once the engine is ticking over, making the car go along was a by-product!

It doesn't *need* to run faster, although within certain limits increasing the speed will increase the available output.

The simplest analogy I can give is as follows. Consider a foot pump unconnected to a tyre. Pushing it down with the foot requires a certain amount of energy.

Now connect the pump to the tyre. The amount of energy needed to push it down will now be higher, and will continue to increase as the pressure in the tyre rises.

I can't see any ambiguity in what I wrote; however, to clarify, any increase in electrical load on the vehicle's system will ultimately need to be compensated for by an increase in power driving the alternator. Clearly this means increased fuel consumption. You can't get something for nothing!

Without any doubt whatsoever.

Chris

NO, but it will nead more torque to turn it , thus the engine will have to supply more power.

Yes, it increases it.

Yes. Whether it's significant is the question.

It's been a loooooooooooooooong time, as Little Miss Jocelyn might say.

Except that isn't there a difference between an alternator (which basically spins freely) and a pump which actually has to pump something physical?

OK, I'd accept that analogy for the various pumps on a car, but not sure about the alternator.

OK, clarified, thanks.

But as I said in the other post, doesn't an alternator spin freely without resistance to be overcome by torque? Or does it just seem that way?

Well if you try spinning it at 5000rpm whilst energised then no, it doesn't spin freely.

Nope.

Duncan Wood ("Duncan Wood" ) gurgled happily, sounding much like they were saying:

Just think of all that effort, energy and emissions that could be saved by power stations if they DID spin freely.

All you'd need was half a dozen hamsters and some gearing, and you'd be able to drive a large enough generator to provide electricity to the whole country.

I'll try another analogy then.

Hopefully, you have used an electric drill at some time in your life. When you press harder on the drill, you can hear and feel the increased load on it. It will also slow down.

In a similar way, when the electrical load on the alternator increases, the magnetic changes that occur within mean that more effort is needed to turn it.

On modern cars, the ECU holds the engine revs constant, so the engine, and therefore the alternator, maintain speed. In order to do that the ECU turns the wick up a bit, generally by increasing the amount of fuel going to the engine.

On older cars, with no ECU, you could often see the rev counter dip if you switched the headlights on at tickover. Why did the speed drop? Because of the increased load.

Chris

Ah, OK, gotcha now.

In message , Terry F. writes

Think of the alternator as requiring a certain amount of force to turn it when it is supplying a certain amount of current. When you up the current demand, it takes more force to turn the alternator, and hence more power is required from the engine. The speed at which the alternator is turning is not really relevant.

In message , TripleS writes

Unfortunately we don't, as a nation, do that very well. That being the case, having a higher judicial authority than the national one might be a Good Thing on balance