Slick-Z

Z28SORR is correct the battery sends voltage to the starter which then cranks the engine and in turn makes the alternator turn due to the belt turning it. this is when the car is running of the battery which is getting all its charge from the alternator. See the battery without the alternator running will run the car for maybe fifteen minutes of drivng around town depending on how good of a charge the battery holds and in what kind of condition it is in. If the battery goes bad such as a bad cell or something then the car will for sure not start once youve killed it and will make the alternator work twice as hard this is all explained thoroughly in your haynes of chilton manual. Ive already been through plenty of bad batteries.

koolaid_kid

I am overwhelmed.
A couple of more (obviously incorrect) links:
http://news.carjunky.com/how_stuff_w...r-cde609.shtml "...the alternator is where the powertrain derives power primarily..."
http://news.carjunky.com/how_stuff_w...k_abc153.shtml "The alternator is an important part of the engine because it perpetuates the reproduction of power. The battery supplies the initial boost the engine needs to start the vehicle. The alternator takes over and replaces the power used in the battery by the starting of the engine..."
http://www.nationsautoelectric.com/function.html "Purpose: The alternator generates direct current for recharging the battery and for powering vehicle electrical loads..."
http://en.wikipedia.org/wiki/Alternator "Alternators are used in modern automobiles to charge the battery and to power a car's electric system when its engine is running..."

There is a symbiotic relationship between the battery and the alternator. But if you increase the current demand of the electrics of the vehicle (such as a huge stereo), you need to increase the alternator capacity, not the battery.

Best of luck folks.

Hood_Lum

I think koolaid is on the right track but misunderstanding his own citings. The alt recharges the batt. So if u have a high power demand u need a bigger alt to recharge the batt cuz the batt drains faster. On that note, if the batt is dead but alt is good the car will run until ur out of gas or u turn the car off because the alt will supply the batt with enough juice to keep things running. A bad batt just won't hold a charge.

STRYKER

I can't speak for the LT1 cars and systems BUT, I know for a fact that on older cars and trucks, once the car is started, the battery can be completely removed from the vehicle and it will stay running. I have done this several times myself. I have taken a battery out of 1 car, put it in my car and started it up, then taken the battery out and put it back into the original car so my buddy could follow me home. And that was about 40 miles away. Once again this was not a LT1 car though. Could it be possible that the ECM gets its power straight from the battery and the rest of the electronics get their power from the alternator ? Kinda like when you pull the PCM / BATT fuse the same thing happens but you still have the stereo and such ......... just a thought.

koolaid_kid

Hood_Lum, you almost have it. Think about this; when the battery needs to be charged up, such as after a long crank time or sitting around for a week or two, the voltmeter in the car will jump up to 13.6 or more volts. This is when the alternator is charging the battery as well as powering the vehicle electrics. After the battery is charged, the voltmeter will drop down but still be above 12.6 volts. 12.6 volts is all the voltage the battery can physically supply. The extra voltage (and hence the power, since P=VI) is supplied by the alternator. This is the period when the alternator is basically supplying power to the car's electronics only. At this point, the battery is a terminal point only, nothing more. No power need go through the battery, why should it? Electrically speaking, it is a resistance, and electricity will ALWAYS follow the path of least resistance, which is the wires themselves.
If you look at the circuit (at least on my 97) the alternator is connected to the positive terminal of the battery, and the positive terminal of the battery is connected to a dual post terminal block on the passenger's side front fender well (under the red plastic cover, if it is still around). This means (electrically speaking) that the alternator output is the same point as the terminal block (minus a small voltage drop due to the length of the cable). Any electrical demand placed on the alternator will follow the path of least resistance, which is from the alternator to the battery terminal to the terminal post block on the fender well.
STRYKER, I once had a Honda that I drove for a year without the battery even being installed. I parked on an incline and push started it, or just got a jump. Once running, the alternator took over, just as it is designed.
I apologize for diverting the true purpose of this thread.

Fatdog2

My friend has an acura,and he needed a new battery,and he went to the dealer and they kept the car running,while they replaced the battery,as to not loose all the radio and gsp and stuff.Once the car gets started,you really don't need the battery from what i gather.And i would listen to a mechanic who has been doing this kind of stuff,rather than someone who is not a bonified mechanic.Just do what the owners manual says and you'll be fine.I 've wasted too much money listining to toro caca.My02.

Hood_Lum

Older cars and trucks don't need batt. Dieseling anybody? lol
Newer cars will stall when batt is taken out though.
Friend's Mitsubishi stalled and it turned out to be a loose batt. cable.

koolaid_kid

From another site, perhaps this will help explain:
http://www.bcae1.com/charging.htm
I don't recommend running w/o a battery, but don't be deceived by thinking a larger capacity battery is needed for anything other than cranking the vehicle. If you increase the demand on your electrical load (like a kicka@@ stereo), use a larger capacity alternator, not battery.

Cashmoney1234

look the battery starts the car and the alternator keeps the battery charged and operating while the vehicle is running it’s that simple but yes a car can run on the battery alone but now for very long without the alternator

STRYKER

Not sure if you noticed, but this thread is over 10 years old...

Rl38ssr

there are different ratings for Batteries regardless of what type of engine you have for year. There are ratings at 0 degrees is called cold cranking amps and ratings set at 32 degrees the one you need to pay attention to is the one that 0 degrees or cca's on average 500 cold cranking amps is sufficient for any 350 engine unless it has had power adders to the engine. The AMG battery known as absorbed glass mat does an excellent job especially with Reserve capacity which base curve additional lights and power adders like power windows. Although I am prejudiced and rightfully so I was a sales rep for batteries for 25 years and I will tell you that AutoZone Walmart Advance Auto Napa O'Reilly's others are good batteries made by the same mfg only under their name. Hope this helps you, you will pay higher for agm but a regular lead acid battery will still take up a good bit of 60 to 85 dollars

Injuneer

gritter94 hasn’t signed into this site in almost 11 years.

shoebox

Two first time posters in one 10 year old thread. That might be a record.

Injuneer

Odd.... a lot of resurrecting ancient posts lately. A shame people don’t want to help with current posts. Often they post once and never come back again.

shoebox

Resurrecting old posts...it's the seemingly unavoidable right of passage for the forum newbie.