No charge to from alternator to battery

the alternator is not charging
problems include incorrect alternator ( internal voltage regulated as against external voltage regulated )
blown rectifier plate ( charing with ac current instead of DC)
drive belt tension
best have it checked by an accredited auto electrician

You could have a bad diode in your alternator. That would cause ripple on the DC output that would result in the flickering. Have the charging system tested. Most testers will detect bad diodes.

The first step is to check all of the battery cables and their connections. Insure that they are CLEAN and TIGHT (visual and physical inspection should ALWAYS be FIRST).

When you are satisfied that there are no problems with corrosion or loose connections, then you must use a battery load tester to load test the battery. On modern batteries, It is also recommended that you use a battery analyzer that can test the battery impednce. Sometimes a battery will show High impedence - even if it can pass a "load" test. Replace the battery if tests indicate it is necessary.

Please note that the rest of the charging system cannot be properly tested until the battery and the cables are all in good working condition.
Any attempts to check the alternator and its circuits with bad cables or battery are going to be, at the very best, inaccurate

Once the battery connections and battery are in good working order, then the alternator output must be tested. It should be tested for voltage output both at idle and at high RPM with a load applied. It should be tested for maximum amperage output to see if it coinsides with the alternator's amperage rating. It should also be tested for AC current or "ripple", indicating shorted diodes.

If the alternator fails any of the tests, then either the alternator should be replaced or the alternator control and output circuits must be diagnosed and repaired (it depends on WHICH test or tests it fails).

Instructions1 Clean the positive and negative battery terminals to ensure a good connection with the tester's clamps.
2 Connect the positive and negative clamps to the appropriate battery terminals. The clamps must make firm contact with the battery terminals or the test results will be inaccurate or the tester may not work at all.
3 Turn the tester on and choose the option for "full charging system test." This will test your battery, starter and alternator and provide the most accurate picture of the problem.
4 Follow the directions on the tester's screen. These instructions will include cranking the vehicle after the battery test is performed, holding the engine at a certain RPM range and turning on certain accessories.
5 Read the results displayed on the tester's screen. The tester should scroll through the results, starting with the battery, then the starter and finally the alternator. An alternator test result showing diode ripple problems indicates a bad alternator.
Thanks

if its not charging while running at14.5 volts or so you have a charging problem mabey no power to the alternator if its charging at 14.5 or so and the batery load tests good and its going dead over night you have a draw from some component in the system.

The battery light is coming on due to either a defective Alternator voltage regulator Diode (built into the alternator) or to a wiring connector problem at the Alternator. When the charging system voltage drops below the battery voltage the battery warning light will come on, this is not a Battery problem as many think, it is a charging system issue as stated above, the main component of the charging system is the Alternator..

Your not over .5 volt ac on the ripple, which
is ac leakage from the diodes

What started this issue & who is doing the testing
& how.

Don't see an issue from those numbers.

Your alternator is putting out good voltage, so internal voltage regulator is working, but what's happening the Diode is what going bad, the alternator put's out ac voltage, and the Diode turn it to dc voltage, could mess up your battery and elec. system, the Diode are like a one way valve, have it checked with a alternator, battery, starter tester, most auto parts will do this for free, if Diode's are bad it will show up in there tester.

Generally, you can check and test alternator with this procedure...

1. Clean the positive and negative battery terminals to ensure a good connection with the tester's clamps.
2. Connect the positive and negative clamps to the appropriate battery terminals. The clamps must make firm contact with the battery terminals or the test results will be inaccurate or the tester may not work at all.
3. Turn the tester on and choose the option for "full charging system test." This will test your battery, starter and alternator and provide the most accurate picture of the problem.
4. Follow the directions on the tester's screen. These instructions will include cranking the vehicle after the battery test is performed, holding the engine at a certain RPM range and turning on certain accessories.
5. Read the results displayed on the tester's screen. The tester should scroll through the results, starting with the battery, then the starter and finally the alternator. An alternator test result showing diode ripple problems indicates a bad alternator.

Hope helps (remember rated this).

Step 2 Connect the positive and negative clamps to the appropriate battery terminals. The clamps must make firm contact with the battery terminals or the test results will be inaccurate or the tester may not work at all.

Step 3 Turn the tester on and choose the option for "full charging system test." This will test your battery, starter and alternator and provide the most accurate picture of the problem.

Step 4 Follow the directions on the tester's screen. These instructions will include cranking the vehicle after the battery test is performed, holding the engine at a certain RPM range and turning on certain accessories.

Step 5 Read the results displayed on the tester's screen. The tester should scroll through the results, starting with the battery, then the starter and finally the alternator. An alternator test result showing diode ripple problems indicates a bad alternator.

Read more: How to Test a Car's Alternator | eHow.com http://www.ehow.com/how_2079784_test-cars-alternator.html#ixzz0spTYveGJ

STARTING YOUR DIAGNOSIS
What happens when you attempt to start the engine? If nothing happens when you turn the key,"http://www.aa1car.com/library/2003/us20310.htm"to determine its state of charge. Many starters won't do a thing unless there is at least 10 volts available from the battery. A low battery does not necessarily mean the battery is the problem, though. The battery may have been run down by prolonged cranking while trying to start the engine. Or, the battery's low state of charge may be the result of a charging system problem. Either way, the battery needs to be recharged and tested.
If the battery is low, the next logical step might be to try starting the engine with another battery or a charger. If the engine cranks normally and roars to life, you can assume the problem was a dead battery, or a charging problem that allowed the battery to run down. If the battery accepts a charge and tests okay, checking the output of the charging system should help you identify any problems there.
A "http://www.aa1car.com/library/2002/cm10220.htm" that is working properly should produce a charging voltage of somewhere around 14 volts at idle with the lights and accessories off. When the engine is first started, the charging voltage should rise quickly to about two volts above base battery voltage, then taper off, leveling out at the specified voltage. The exact charging voltage will vary according to the battery's state of charge, the load on the electrical system, and temperature. The lower the temperature, the higher the charging voltage. The higher the temperature, the lower the charging voltage. The charging range for a typical alternator might be 13.9 to 14.4 volts at 80 degrees F, but increase to 14.9 to 15.8 volts at subzero temperatures.
If the charging system is not putting out the required voltage, is it the alternator or the regulator? Full fielding the alternator to bypass the regulator should tell you if it is working correctly. Or, take the alternator to a parts store and have it bench tested. If the charging voltage goes up when the regulator is bypassed, the problem is the regulator (or the engine computer in the case of computer-regulated systems). If there is no change in output voltage, the alternator is the culprit.
Many times one or more diodes in the alternator rectifier assembly will have failed, causing a drop in the unit's output. The alternator will still produce current, but not enough to keep the battery fully charged. This type of failure will show up on an oscilloscope as one or more missing humps in the alternator waveform. Most charging system analyzers can detect this type of problem.
thanks,please rate the solution positively.