not using radio?

[KU40]

Originally Posted by DracoFelis

BUT, almost all alternators put progressively more drag on the engine, as your electrical usage goes up!

I actually said that in my post.

[theholycow]

So, which is it...is there a baseline amount of power generation that gets wasted if it's not used, or does it only make however much is needed?

With the little I understand about it, I'm pretty sure it only makes as much power is needed.

[R.I.D.E.]

Think of your battery as a tank of water. The alternator refills the tank until it gets full, then waits until the level drops off to refill the tank again.

Those who think the energy drain of an alternator is constant just dont understand the fact that the battery voltage level "tells" the alternator

Charge me
Dont charge me

If this was not the case all batteries would be overcharged into oblivion in a very short time, with the electrolyte cooked out of the battery.

regards
gary

[R.I.D.E.]

KU40 most alternators do not have the capacity to charge at rate greater than all potential drains combined.

Thats why if you jump start a car and rev up the engine in the good battery car, you can fry the charging system in that car.

Maximum potential drain is far in excess of the charging systems capability. Cranking loads are generally several times the charging systems capacity.

My car runs at a higher idle speed after a hot restart for a short time until the loss from cranking is recovered.

regards
gary

[theholycow]

Put simply: You will not see measurable FE gains as a result of turning off an original equipment radio.

[VetteOwner]

Originally Posted by DracoFelis

And that is where we actually agree! In fact, I even implied as much in more than one previous post I did in this thread.

i.e. Yes, using the radio uses some electricity, and using electricity will (under most conditions) lower your fuel economy some (due to the increased alternator drag on the engine). However, unless you have one of those big power hungry after-market stereos, there are usually other places in the car that use much more (electrical) power than the radio. And working on lowering the (electrical) power usage of those other sources, will often yield much more satisfying (fuel economy) results than simply leaving the radio off!

yes the brakelights /tailights draw more amps than the radio does... even switching those to LED wont give you measureable results.

so really if it came stock on the car leave it and use it

[Dalez0r]

I read someone's post here today who said he ran a radio off a second battery, without charging, and it lasted several days before it got low. Given that a car battery stores very little power really, I'd say the average consumption is a small fraction of a hp in the end.

[KU40]

Originally Posted by R.I.D.E.

Think of your battery as a tank of water. The alternator refills the tank until it gets full, then waits until the level drops off to refill the tank again.

Those who think the energy drain of an alternator is constant just dont understand the fact that the battery voltage level "tells" the alternator

Charge me
Dont charge me

If this was not the case all batteries would be overcharged into oblivion in a very short time, with the electrolyte cooked out of the battery.

regards
gary

Well see I guess this is where I'm misinformed. I've always just seen graphs of alternator output with only engine RPM and amperage output. So I assumed that amperage output had a direct relationship with engine speed. So RPMs go up, amperage goes up regardless and the voltage fluctuates from the voltage regulator. I thought electricity produced would be fixed at a given RPM because the bearings would be spinning at a certain speed and the amount of windings inside the alternator were fixed, giving off a fixed amount of power per RPM.

I've just seen these graphs when looking at aftermarket pieces and I guess they don't indicate the load placed on the system for the test.

[VetteOwner]

Originally Posted by Dalez0r

I read someone's post here today who said he ran a radio off a second battery, without charging, and it lasted several days before it got low. Given that a car battery stores very little power really, I'd say the average consumption is a small fraction of a hp in the end.

yup, in lemens terms, its like saying i wont drink this bottle of water because it will affect the gas mileage from the added weight...