How to Load test an alternator ?
Fas idle....1200 rpm 14,4 volts 100 amp alternator HF 500 amp carbon pile load tester connected to battery. Using logical thinking only,........ If I gradually load the system, at what amperage...
Forum Discussion
Chances are that the voltage at the alternator output will be about 1 volt higher than the battery voltage where the load tester would be connected under a 100 amp load. THis is due to the #8 wire running between most alternators and the battery. The small wire will prevent alternator overloads - I guess?
So how to put a 100 amp load on a battery with a 500 amp load tester? Can you divide the load up into 100 or 50 amp sections, and only put that load on the battery?
I would expect the voltage to drop into the 13.8 volt range at 100 amps load on it. Just because of the voltage loss across the internal diodes within the alternator. Also as the alternator warms up, most manufactures claim that they will only put out about 80% of their cold rating. Yes you already realize that many require at least 2,000 alternator RPM to put out anything near the rated amperage.
Fred.
So how to put a 100 amp load on a battery with a 500 amp load tester? Can you divide the load up into 100 or 50 amp sections, and only put that load on the battery?
I would expect the voltage to drop into the 13.8 volt range at 100 amps load on it. Just because of the voltage loss across the internal diodes within the alternator. Also as the alternator warms up, most manufactures claim that they will only put out about 80% of their cold rating. Yes you already realize that many require at least 2,000 alternator RPM to put out anything near the rated amperage.
Fred.
