A simple test is to start the engine and let it run at idle. Connect a digital multimeter set to 20 volts DC to the battery. Red to + and black to -. If the alternator is good you will read from 13.5 to 15.5 volts. This tells you allot but is not a definitive test. To test it completely drive to your local auto parts store and have then test it under load. Most will do this for free.
Charge it, replace it,test the alternator,Charge it, replace it,test the alternator,
it is the activity that not do to work already that is the test efficiency a plan
Car would either have to be running or alternator removed for bench test
run it and then disconnect the negative wire from the battery if alternator dies its bad.
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with a voltmeter
the efficiency of transformer is more than alternator, because 1- the alternator have friction and windage loss but in transformer this not occure. 2- in the alternator the flux leak is more than the transformer, because in case of alternator the flux move through the air which is dimagnet and in transformer flux move through silicon steel. 3- in the other hand alternator have dc compound generator for exciation (depend on other electric course 220volt) but in t/f is not need.
Either drive to your local auto parts store and have them test it in the vehicle or you can remove the alternator and take it to your local auto parts store and they can bench test it for you.
Short circuit test and open circuit test are widely used to test the efficiency of the transformer.
Full fielding is a diagnostic test of the alternator You make the alternator work full out and measure the voltage and amperage output to test it against a published specification.
yes
Battery light usually means alternator not charging. Most common solutions would be be a bad alternator, bad connection, or loose alternator belt. If the battery and alt test ok than check the connections to the alternator and battery.