car heaters question?

Pew_Pew_Pew_Lasers!

The battery, as stated above, is required for the car to run.

The alternator charges the battery while the engine is running. Thats why alternators have a clutch.

The real thing to remember with regard to using equipment is on short journies during winter. You're using the fan to heat the cabin, the rear screen heater for visibility, the radio, the lights, and on a diesel the glow plugs.

Its a tremendous strain on a battery, especially on a short journey when the alternator will not have enough time to recharge the battery. Its even worse in the winter as the low temperatures have an adverse effect on the chemistry of the battery.

If you experience difficulty starting the car, with the starter motor turning the engine very slowly, its time to investigate getting a new battery.

Wig

People without A/C or those with it but don't use it, generally don't drive around with all 4 windows down or even the front two windows. Except maybe in very hot weather in a town centre at a slow speed when 'drag' effect will be less apparent.

When the car speeds up most people would wind the windows up completely or just leave a 2 inch gap. They could then use the fan on cool setting. - Unfortunately modern cars do not let any (or very little) air pass into the cabin without the fan on - old cars used to have tubes directly linked to the outside and you opened the vent and got a blast of cool air without the need for a fan.


I'd like to see the results and test criteria of this "test" previously mentioned. My instincts tell me that town centre driving would be more efficient with windows down than with A/C on. And motorway driving with the vents/fan on cool, the windows slightly open or the sunroof open to the rear, would be more efficient than with A/C on.


My answer to OP, is like most others,
A/C uses lots of extra fuel ( by comparison with other electrically powered functions)
Put the interior heater on with the fan on as much as you like, though a slower fan speed IMO is less noisey, uses less power and is therefore more comfortable.
Use the rear screen hearter sparingly, once it has cleared turn it off.

thescouselander

goldspanners wrote: »

is this meant to be a serious reply?
you are so misinformed,go and disconnect the battery in your car with the engine running and see what happens.
or i could tell you.
the basics of it is,the battery is there to complete the circuit,disconnect this = no power anywhere,fuel safety solenoid will shut off, ecu will shut down, alternator will not be gettign any feedback from battery, etc,etc... the list goes on.
in theory your car could run without a battery,like old cars with start handles,but there is so much electronics in your car these days,and even days gone by that the battery needs to be connected.
just to exagerate this a bit,if you have ever tried to jump start another car with a petrol car you will have noticed as soon as you connect the last jump lead the engine will start to labour (or fan belt will squeal) this is due to the extra load being put on to the engine via the higher amperage required out of the alternator which in turn equals more fuel being used.
so the short answer is yes,using any electrical item which is using power from the car it will use slightly more fuel,not enough to really notice though.(except a/c of course thats different)

No, I am not miss-informed, the battery is not there to complete the circuit, it is basically wired in parallel to the alternator (not series). The alternator needs no feedback from the battery once the engine is running because the field windings can be powered from the alternator itself. Feedback from the battery is only needed for the field windings at engine start before the alternator is generating anything.

The alternator can sustain enough power to run everything on the car and charge the battery at the same time - if it couldn't then the battery would eventually run flat.

I would suggest it is you who is miss-informed

goldspanners

thescouselander wrote: »

I would suggest it is you who is miss-informed

please please please go out start your car and take the battery out,go on i dare you.
it needs the battery connected to run.

thescouselander

goldspanners wrote: »

please please please go out start your car and take the battery out,go on i dare you.
it needs the battery connected to run.

I dont need to, I have already done this before. Also if your battery goes pop you can still jump start the car and the car will then run.

Also, I am a chartered electrical engineer and have designed more electrical circuits than you can shake a stick at. I am quite familiar with electrical systems and I can assure you that my post is quite correct.