200 Amp Alternator Voltage Output?
Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=18199
Printed Date: July 15, 2025 at 7:57 AM
Topic: 200 Amp Alternator Voltage Output?
Posted By: JustDoIt2
Subject: 200 Amp Alternator Voltage Output?
Date Posted: August 28, 2003 at 11:46 AM
HI, I got a 200 amp alternator and I would like to know if the voltage the car is giving is right or not. When THe engine is running without pressing the Gas Pedal and with the radio off. the voltage is 12.4-12.5 but WHen I turn On THe Radio and the Equalizer,, the voltage to the Head unit and the equalizer drop to 11.8-11.7 and When the BASS HIT really hard the Voltage drop to 11.0-11.1 and when I press the gas pedal the volstage goes up to 13.4-13.2.............. WHAT DO YOU GUYS THING?
Replies:
Posted By: nedgeworth
Date Posted: August 28, 2003 at 4:03 PM
Well basically most alternators are specified at for example say 200amps at maybe 2500rpm. If you have got your hands on a cheap HO alt more likely higher rpm than normal is needed to produce 200amps. You might need to look at getting yourself a new battery as well to help out with things.
Posted By: italnpimp59
Date Posted: August 28, 2003 at 7:45 PM
yeah sounds like you need a new battery. an alternator will help when you have a system or anything that draws lots of current. it will keep your car from stalling. but as far as the voltage...the alternator will keep charging the battery up to its CURRENT capacity. if the battery is old and needs to be replaced...then yeah all you will get is like 13-13.5 volts. get a new battery and surely you will see 14+ volts!
-------------
Posted By: auex
Date Posted: August 28, 2003 at 9:29 PM
First, definately try a new battery. Then if votage doesn't go up to at least 13+ volts at idle then take the alternator back.
-------------
Certified Security Specialist
Always check info with a digital multimeter.
I promise to be good.
Tell Darwin I sent you.
I've been sick lately, sorry I won't be on much.
Posted By: bberman1
Date Posted: August 29, 2003 at 10:08 AM
That may be normal I see allot of people that upgrade there alternators and have the same question. most alternators will not put out very much current at idle speed . When looking at high output alternators you always want the highest output at the lowest rpm. As far as the battery goes with the car on the voltage depends on the alternator not the battery. So there is probably nothing wrong with the battery however you can test it if you have a voltage meter.
This is with the car off
A healthy battery is about 12.2 - 12.8 volts
A not so good battery ( but still operational ) is about 11.4 - 12 volts
A battery needing replacement will read under 11 volts ( about 10.5 - 10.8 )
Posted By: JustDoIt2
Date Posted: August 30, 2003 at 12:19 PM
The Battery is New too, I ought a Optima Yellow Top, Paid $150.00
Posted By: JustDoIt2
Date Posted: August 30, 2003 at 12:22 PM
With the Car off the voltage is 12.6. Its Only when the car is running and not pressing the gas pedl, as soon as I press the gas pedal the voltage goes to 12.8-13.0
Posted By: wizzle
Date Posted: August 31, 2003 at 2:26 AM
is the ground on the alternator the same size as the power wire?
Posted By: mj239air
Date Posted: August 31, 2003 at 7:36 AM
Anyone know how to check the AMPs that the alternator is putting out?
Posted By: JustDoIt2
Date Posted: August 31, 2003 at 6:12 PM
THe alternator is a GM, Only POsitive, not ground..
Posted By: DYohn
Date Posted: September 01, 2003 at 7:59 AM
Sounds to me like your alternator is functioning properly. If you need more available current with the car idling, you may be looking at needing additional batteries. mj239air, unless you know what you are doing and have the correct equipment, DO NOT try to "see how many amps" the alternator is producing. You can easily hurt yourself by blowing up a meter in your face if you don't know how to do this, and cheap meters from Radio Shack will NOT handle the amps from any car alternator. Don't try it. Take it to a shop for help.
Posted By: mj239air
Date Posted: September 01, 2003 at 8:31 AM
Thanks, I was just wanting to know if there was a way. I know how to check voltage, didn't know if an easy way to check amps. Don't really care to try.
|