Truth?

[mokedaddy 5,000+ posts]

Err?
Everything runs off the alternator when the car is running. The batteries main purpose is to start the vehicle and to help with any high draw demands. The alternator supplies all the current that the car is demanding.

Nothing runs directly off the alternator. The power wire from the alt goes to the fuseblock where it is then distributed out to the rest of the car. Remember when the mythbusters did that test with the bullet for a fuse for the HEADLIGHTS? They replaced the headlight fuse with a bullet. How could they do that if the headlights run directly off the alternator?

Like said the batteries main purpose is to smooth voltage ripple. I have yet to see a car that has a fuse block directly to the alternator so I am not sure what you are actually saying. I have seen them fused at the main block run to the battery and back to the fuse but not directly powering the fuse block. Not to say it doesnt happen but it kind of makes the battery obsolete as far as smoothing the ripple.

And by running off the alternator, I obviously didnt mean directly, but it will supply the power since the battery usually cant keep up.

 

[ultimate157 5,000+ posts]

Like said the batteries main purpose is to smooth voltage ripple. I have yet to see a car that has a fuse block directly to the alternator so I am not sure what you are actually saying. I have seen them fused at the main block run to the battery and back to the fuse but not directly powering the fuse block. Not to say it doesnt happen but it kind of makes the battery obsolete as far as smoothing the ripple.
And by running off the alternator, I obviously didnt mean directly, but it will supply the power since the battery usually cant keep up.

The alternator provides the power most of the time because the output voltage of the alternator is higher than the resting voltage of a 12v battery. With a higher voltage potential, that is the source.

Its only when the load exceeds the output of the alternator, and the alternator output voltage drops to below the resting voltage of the battery, that the battery begins supplying current.

 

[PaulD 10+ year member]

The REAL answer is that you have TWO sources of power while the car is running, and one while it is off.

ONLY if you draw so much power that the voltage sags below like 12.5 volts. Being that I am into SQ (Which was the question I was responding to) This really isn't an issue.

 

[ultimate157 5,000+ posts]

ONLY if you draw so much power that the voltage sags below like 12.5 volts. Being that I am into SQ (Which was the question I was responding to) This really isn't an issue.

Go ahead and read the whole response, that was covered.

 

[PaulD 10+ year member]

Jesus fvck, I hope you're kidding.
The battery and alternator share the job of supplying power to a running engine. Typically, the 3 meet at the (+) battery terminal, where the alternator and battery become a single power source, from which the fuse block draws power. In order for the two to work in a particular order, the battery-to-fusebox connection would have to be switched.

NO, NO and ummm NO ..... You can take the battery out of the car after the car is started and it will still run (in a non-modded car). The alternator power is run directly to the fuse block (at least all the ones I have seen lately). Now if you have installed an HO alternator and run that "power" wire straight to the battery and disconnecting the battery breaks the link, then you will not be able to do that.

 

[PaulD 10+ year member]

I think you guys are looking at your heavily modded electrical systems, required for the huge bass systems the vehicle is housing, and missing the big picture.

The reason why I don't need 300A alts and mega batteries even though the systems amps are capable of nearly 4000 watts RMS is the type of music I listen to. SQ music, even at high volumes, use much less average power. The additional power is for headroom, the crest factor of a CD can be around 30 dB, that's a power factor of 1000.

EDIT: In the design of the vehicle from the factory, the alternator is designed to have enough power to run all the accessories when the car is on. The battery is actually just another load on the alt that must be recharged after starting the vehicle. The battery was NEVER designed as a secondary power source for running the vehicle.

 

[mokedaddy 5,000+ posts]

The alternator provides the power most of the time because the output voltage of the alternator is higher than the resting voltage of a 12v battery. With a higher voltage potential, that is the source.
Its only when the load exceeds the output of the alternator, and the alternator output voltage drops to below the resting voltage of the battery, that the battery begins supplying current.

Kind of but not exactly. Batteries have the potential to float above their 12.8 voltage thus why you get higher voltage when being directly charged.

 

[mokedaddy 5,000+ posts]

NO, NO and ummm NO ..... You can take the battery out of the car after the car is started and it will still run (in a non-modded car).

That is a very good way to fry an ecu.

 

[mokedaddy 5,000+ posts]

EDIT: In the design of the vehicle from the factory, the alternator is designed to have enough power to run all the accessories when the car is on. The battery is actually just another load on the alt that must be recharged after starting the vehicle. The battery was NEVER designed as a secondary power source for running the vehicle.

The battery smooths voltage from the alternator. Alternator voltage can and does spike. Thus why it will fry onboard electronics.

 

[tommyk90 5,000+ posts]

That is a very good way to fry an ecu.

The battery smooths voltage from the alternator. Alternator voltage can and does spike. Thus why it will fry onboard electronics.

I recall one MECA competitor who used strictly alternators in his competition vehicle and never had a problem (dominic irragi).

Granted it was an older vehicle and for competition purposes, but he never fried anything.

 

[mokedaddy 5,000+ posts]

I recall one MECA competitor who used strictly alternators in his competition vehicle and never had a problem (dominic irragi).
Granted it was an older vehicle and for competition purposes, but he never fried anything.

That kind of disqualifies my point. Could be the vehicle didnt have an ecu. Could be he wasnt running the air or headlights. Could be the alternator(s) could handle the load and didnt spike. Nothing is always black and white but I know I wouldnt try it. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[tommyk90 5,000+ posts]

That kind of disqualifies my point. Nothing is always black and white but I know I wouldnt try it. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

I wouldn't either seeing as I kind of need a battery to start my truck. //content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif

Older vehicles are much different from newer ones in pretty much every aspect.

 

[mokedaddy 5,000+ posts]

I wouldn't either seeing as I kind of need a battery to start my truck. //content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif
Older vehicles are much different from newer ones in pretty much every aspect.

yeah I edited a little bit. But I definitely agree new cars are a completely different animal.

 

[yischrax 10+ year member]

I think that Dominic Irrigi is a bit difrent than the rest of us seeing as how he BUILDS alts. He could easly use 3-4 times the rectifiers that any of us have in any alt. We will ever own bringing down the amount of a/c ripple from the alt. This thread is just repeating itself now. It seems like some people arent grasping the info that others are giving them and so they continue to repeat themself over and over again and the people who understand have already lost intrest. THREADS dead.

 

[pawn man 10+ year member]

ignore the circle and arrow