Do you put the heater on in the car?

Strider590

adouglasmhor wrote: »

Just listen to an engine change tone when your fans kick in.

Im fully aware of this..... But you seem to be suggesting that the alternator physically grabs the engine and slows it down. Which is utter non-sense.

The change in engine tone is down to the dip in voltage when you switch on a device, it the same way that turning on your kettle causes the lights in the house to dim for a split second.

Because the ignition coils, the fuel pump and a myriad of other vital functions are fed from the cars electrical system, ANY drop in voltage will affect the engine at tick over BECAUSE at tick over the alternator is NOT running at full generating capacity, it may only be able to supply 30A instead of 70A+......
(At higher RPM the additional current drain is negated almost completely)

In which case anything more than 30A is going to drop the voltage to under that of normal conditions (typically 13.5vDC), which then has to be supplemented by the battery

Then because lead acid batteries cannot handle being discharged for long periods without damage occurring (sulphation) AND in combination with the optimal temperature of a lead acid battery being 25 degree's C (which is fine once the car is warm), this is why car batteries tend to fail during the winter months. Low charge state + poor idle/storage conditions.

But who am I to know this, I only carried out electrical component validation work for the largest car manufacturer's in Europe.

Lum wrote: »

Heat and noise

If the sockets in your house make a noise when nothing is connected, I would suggested calling your local sparkz

I also have 16th edition regs

Lum

The sockets don't make a noise but some mobile phone chargers do.

As for wiring faults, if that is faulty I'll just add it to the list of things the landlord won't ever bother to fix like the window with the broken catch that we've had to tape up to keep the drafts out.

thescouselander

strider - I'm sorry, thats bollox, your explanation is way off the mark. The alternator does supply the electrical load and in doing so it does increase resistance on the engine. I wouldn't recommend doing this on a modern car incase you upset any of the many ECUs but if you were to remove the battery from a running car it would continue to run because the alternator is providing the power.

The proof is very simple - just do a simple network analysis with the alternator and battery and a resistive load to represent the car - you will see that the alternator must pick up the load due to its higher potential.

skiddlydiddly

We had this alternator debate a while back and I was with yiou, but after I read up on it I saw I was wrong.Its to do with as more power is demanded of the alternator it makes a stronger electrical field in the motor and so makes it more difficult to turn, thus drawing more power from the engine to turn it.

Strider590

^^ So if you shorted out the alternator (absolute maximum load) it would be physically impossible to turn?

I've got one from my old Pug lying on the garage floor, I can go try this..... But I know what will happen.

thescouselander

Strider590 wrote: »

^^ So if you shorted out the alternator (absolute maximum load) it would be physically impossible to turn?

I've got one from my old Pug lying on the garage floor, I can go try this..... But I know what will happen.

Not impossible but it would be very difficult to turn. The only problem with using an alternator not connected to anything is that you will need to energise the stator coils with a battery. Go ahead - try it, just dont spin the thing too hard or you might brake something - perhaps a battery powered drill would do.


Also, have a look at this

http://www.bcae1.com/charging.htm

skiddlydiddly

I'm not an electrician Strider, I just read up about it and I think as more power is demanded and goes through the motor the magnets become stronger so its harder to turn, which means the engine loses that power in order to do so.

johnnyroper

Strider590 wrote: »

The alternator does not place any addition mechanical load on the engine, no matter how much electrical power you use.
To suggest that the alternator somehow applies an additional mechanical force when you use more power, is totally illogical

The alternator over produces electricity, this electricity is used to recharge charge the battery, but once that is fully charged the electricity being produced simply goes to waste.

On the same principle that power stations want to balance the load throughout the day as a power station burns just as much fuel at night as it does during the day, but at night there's a HUGE wastage.... Hence schemes such as economy 7 (Or whatever it is now).

what a load of bo11ox as more demand is placed on alternator to service electrical loads like heaters etc then the engine load is also increased.
why do you think the idle speed is affected the more electrical loads are switched on?

johnnyroper

Strider590 wrote: »

Im fully aware of this..... But you seem to be suggesting that the alternator physically grabs the engine and slows it down. Which is utter non-sense.

The change in engine tone is down to the dip in voltage when you switch on a device, it the same way that turning on your kettle causes the lights in the house to dim for a split second.

Because the ignition coils, the fuel pump and a myriad of other vital functions are fed from the cars electrical system, ANY drop in voltage will affect the engine at tick over BECAUSE at tick over the alternator is NOT running at full generating capacity, it may only be able to supply 30A instead of 70A+......
(At higher RPM the additional current drain is negated almost completely)

In which case anything more than 30A is going to drop the voltage to under that of normal conditions (typically 13.5vDC), which then has to be supplemented by the battery

Then because lead acid batteries cannot handle being discharged for long periods without damage occurring (sulphation) AND in combination with the optimal temperature of a lead acid battery being 25 degree's C (which is fine once the car is warm), this is why car batteries tend to fail during the winter months. Low charge state + poor idle/storage conditions.

But who am I to know this, I only carried out electrical component validation work for the largest car manufacturer's in Europe.



If the sockets in your house make a noise when nothing is connected, I would suggested calling your local sparkz

I also have 16th edition regs

16th edition is nowt to do with car electrics.

have a look at this web article to gen up on how an alternator works.

https://www.!!!!!!!!!!!/items/1869457-how-an-alternator-works

link will not post but put in helium dot com where all the !! are

adouglasmhor

Strider590 wrote: »

Im fully aware of this..... But you seem to be suggesting that the alternator physically grabs the engine and slows it down. Which is utter non-sense.

The change in engine tone is down to the dip in voltage when you switch on a device, it the same way that turning on your kettle causes the lights in the house to dim for a split second.

Because the ignition coils, the fuel pump and a myriad of other vital functions are fed from the cars electrical system, ANY drop in voltage will affect the engine at tick over BECAUSE at tick over the alternator is NOT running at full generating capacity, it may only be able to supply 30A instead of 70A+......
(At higher RPM the additional current drain is negated almost completely)

In which case anything more than 30A is going to drop the voltage to under that of normal conditions (typically 13.5vDC), which then has to be supplemented by the battery

Then because lead acid batteries cannot handle being discharged for long periods without damage occurring (sulphation) AND in combination with the optimal temperature of a lead acid battery being 25 degree's C (which is fine once the car is warm), this is why car batteries tend to fail during the winter months. Low charge state + poor idle/storage conditions.

But who am I to know this, I only carried out electrical component validation work for the largest car manufacturer's in Europe.

Yet you think potential difference is the same as energy!
Staggering.