Alternator not delievering a charge

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

12.3 volts & a battery over 4 years old or newer-- it's bad

amps or volts
11 to 12 amps indicates nothing but if it is volts then it indicates that the alternator is not charging the battery
Battery voltage is 12 -13.5 volts and when charging is 14.5-14.8 volts dc
the rest of your statement indicates that the alternator or voltage regulator is faulty and you should have the charging system checked by an accredited auto electrician

sounds like your alternator isnt functioning correctly.
you can have this tested at a local garage, normally for free. when the engine is running, it should show around 14 amps on a multimeter. also check the battery is serviced. check the fluid levels and a full charge

There seems to be a no charge state in this case. I recommend checking the charging system. use the procedure below to isolate this issue.

Wear protective eye wear and clothing and remove all jewelry when checking your battery and charging system. Jewelry is a good conductor of electricity and is not recommended. Most batteries wear out every 3 to 5 years and need to be replaced. Always replace your battery with an equal replacement battery to assure proper operation. Automotive batteries have a +positive terminal (red), - negative terminal (black). Electricity is stored in the battery and then supplied to the vehicle when the engine is not running. While the engine is running the vehicles alternator charges the battery for future use. (Note: never disconnect the battery while the engine is running. If the battery cable is disconnected from the battery a spark can be generated which can cause the battery to explode or a major electrical malfunction to occur.)

To check a battery surface voltage, remove the positive terminal protective cover. Connect the +positive side meter lead (red) to the positive side battery terminal. Connect the - negative (black) side meter lead to the negative battery terminal. With the vehicle not running and the car sitting over night the battery voltage should be between 12.5 and 12.8 volts.(You will need to use a voltmeter for this testing procedure)

The alternator is rotated by a drive belt driven by the vehicles engine while it is running. Electrical voltage and amperage are generated to recharge the battery and supply voltage to the electrical system of the car. The alternator is held in place with mounting bolts. There is a main electrical wire on the rear of the alternator that supplies voltage to a main voltage junction box. If your alternator is not charging properly, your battery will slowly drain down from operating all the electrical systems in your car and stop the car from running.(most non charge states will be the cause of a loose belt or a low tension rate, due to a mis-adjusted alternator. make sure you have enough tension in the belt for full rotation of the alt pulley)

Next, you will need to check the alternators output with the Amp meter.

Testing the amperage output of the alternator is good for measuring the amount (not the level) of voltage the alternator can produce. This test can be tricky because if the alternator is weak it can still show it as producing amperage. Which is good, but if the voltage is low, it will still allow the battery to go dead. To check the amperage output of an alternator an amp meter is needed. Once the meter is connected start the engine. Next turn on all electrical accessories and raise the engine idle to about 1200 RPM. The alternator should output the max amperage it was designed to produce. Example: a 90 amp alternator should output about 88 amps. Note: An alternator cannot sustain maximum output for long periods of time. If the alternator is forced to operate at maximum output it will overheat and fail. An alternator is designed to operate at max amperage output only for a reasonable amount of time.

((Connect the voltage meter lead the same way you would in a battery static voltage check, Start engine (do not drive) at engine idle the voltage should be between 13.6 to 14.3 volts. If not the alternator may need replacing.)))

A charge rate of 13.2 is fine...Likely your battery is getting older and is not charging as well as it used to. You should periodically re-charge the battery using an external charger, as the alternators actual function is to maintain the batteries state of charge, not to re-charge it. Opening the doors, playing the radio with the engine off etc, can and will drain your battery. The alternator will only put a surface charge there and will not actually replace this lost power. I'd begin to worry if charge rate dropped below 12.9.but even then you likely would not have any real problems.

sounds like a bad battery check with a hydrometer if cells show full charge replace battery

If you had a dead short when connecting the neg. battery cable, the battery was being installed backwards or you had grounded the alternator + lead somhow.

I suspect whnen you installed the battery, you have burnt all of the diodes out in the alternator and the AMP meter is showing no charge. The AMP meter also could have taken a beating in the reversal.

Check the battery in in correctly first. If not reinstall or get the correct battery. Then check the battery voltage with the engine running. If less then 13.2. Replace the alternator again.

Good Luck

if the alternater light is not on the battery.probably has a bad cell

i would replace the starter and while u do that check the flywheel for damage sounds like it may have a bad connection or bad starter