Installed a new alternator and it still does not show it is charging the battery. i tested the alternator and it is showing 14.2 volts coming from the power lead but not at the battery terminal..

That only means, with your explanation, the battery is bad or has a dead cell. It happens. Have the battery fully charged at a battery rebuilder and have him load test the battery to find if indeed it is bad. If not, have your charging system checked. A test when running should show 14 volts or better, meaning the charging system is good. If the test shows the battery stays at 12 volts, it is not charging and your alternator is at fault.

Check the voltage at the alternator big wire. 14 volts? check at the battery, 12 volts. The wire is corroded or bad. If the alternator lead is showing battery volt(12) check the alternator plug. Pull it off, With key on it should show 12 volts one one wire and ground on the other. Takes at least test light to confirm this

How do you know it's only putting out about 1/2 ? an 1/2 what ? Amps or volts ? Did you hook up a volt meter to the battery posts ? red to red an black lead to negative post of the battery ? Does it show 13.1 to 14. 1 volts with the engine running , if so it's charging . The only thing that would cause the alternator not to put out full charge amps would be a bad diode inside the alternator or a power or ground issue. You need to check power an grounds doing a voltage drop test . Voltage Drop Testing the Charging System

Not on new vehicles , you never ever pull a battery cable while it is running ! A voltage spike can take out electronic components ! That was 60's an maybe a few 70's vehicles ! That change when they started using transistors in voltage regulators an in engine modules. If it is show 14 volts it's charging ! I will send a link on how you test the charging system. How To Check Charging System EricTheCarGuy

Not sure I follow the story. The alternator is charging 100amps but the gauge shows less than 14 volts ? Is the alternator output at least 13.5 volts and is that getting to the battery ?

Maybe it wasn't running long enough to charge up the battery?
Stop trying to jump it, when you are having problems with it dying, take the battery off and have it charged. And/or buy a $20 voltmeter to see what the battery shows. If it says less than 12 volts, it is discharged, and needs charging. A good battery that is not run down should have at least 12.5 volts. A new battery that is charged should have very close to 13 volts, maybe 12.8 volts.
When you have the truck running, check the alternator for charging. You put the voltmeter right on the battery and check it again. This time, with truck running, battery should show at least 13.5 volts. That shows the alternator is working. A good alternator will put out about 13 or 14 volts-the regulator will keep it from going any higher to prevent problems, like a melting battery or electrical parts burning out.
I would say get the charging system working right, then address the problem of dying at stop lights. That could be a carburetor problem, if the alternator is working.

it may have deffective diode on the charging system(the alternator). 14 volts is an over charge in a battery. ampere reading must be on what the battery designed.

Hello
The normal charge of alternator on idling is about 13 to 14 volts. 12 is acceptable but keep in mind it will need attention soon. The needle fluctuates due to the revs of the alternator - there is nothing to worry about. Just look that the charge is always above 12V on idle.

You shoulld expect more than 12.8 volts from the alternator up to nearly 14 volts when charging a low battery. The battery can only show the amount of voltage your alternator is sending to it after being used for a while. I would suggest that you have the battery tested & recharged completely, your voltage will be above 12 volts and if it returns to below that , you will know your alternator is not charging. Also, if you test the output of the alternator and see it is below 12 volts after the battery is fully charged at 12+ volts you will have confimed the problem also.

good luck.

I think your battery is weak, where as it doesn't have the cranking amps when you first go to start it. What i would recommend is doing a load test on the battery to tell for sure if it is good or not. If you have an advance auto or auto zone near by, they offer that service for free, and if need be they will install your new battery for you.
Good luck!