Heavy Duty Alternator

While the benefits of using Remote Sense-equipped alternators are clear, this advanced technology also adds a few additional – yet very simple – steps to traditional alternator diagnostics. Follow these few basic checks to ensure accurate diagnosis of the system.

Step 1: Begin at the batteries

As with any charging system, all troubleshooting begins at the batteries. Always be sure to visually inspect the batteries, make sure they are at a minimum 75% state of charge (12.3 – 12.4 volts), and that they pass a load test.

Step 2: Perform a voltage drop test

This test should be conducted on the main positive and negative cables connecting the alternator to the batteries. As a refresher, the battery cables should not show more than .5 volts (½ volt) loss between the alternator terminals and the battery terminals when the full rated output of the alternator is applied.

Step 3: Determine output voltage

Start the engine and connect a Digital Multi Meter to the positive and negative 
terminals of the alternator to determine the output voltage. It is normal to see an above-average output voltage (in the range of 14.7 – 14.9 volts) at the alternator terminals, since the job of the Remote Sense alternator is to compensate for cable resistance. Move the Digital Multi Meter to the battery terminals and observe the voltage there as well, which should be in the range of 14.0 – 14.4 volts.

Step 4: Check additional wiring

A properly-installed Remote Sense alternator will have a small wire that connects the alternator’s Remote Sense terminal to the batteries. Examine the full length of the wire for proper routing and signs of rub-through or abrasion.