You can use a multi meter and connect it to the battery and set it for like 20 volts dc. Crank it up and see what it's reading. It should read about 13 volts or more. You can turn on the lights and see if it still reads the same. It should. If it's lower than 13 I would assume that it's not charging properly.
Drive the vehicle to your local auto parts store and they will test your charging system at no cost.
new alternator not charging the battery
The warning light comes on because the charging system is failing. Have your local auto parts store test the charging system to determine the cause. They will perform the test at no cost.
The Alternator.
The Alternator.
Recharge, replace, test charging system.
Drive the car to your local auto parts store and they will test the charging system to determine what the problem is, at no cost.
Your charging system is not working. It could be the Alternator or the regulator or both. It's not a good idea to test the charging system by removing a battery cable while engine is running, this can damage the charging system.
The Alternator.
I'd recommend you do a battery test and charging system test. The battery would be my first suspect.
You will need to go to a repair shop and have them test the charging system.
A charging system test is done to check the internal voltage regulator. It can be done at any auto parts place.