Advanced Marine Electrics and Electronics Troubleshooting A Manual for Boatowners and Marine Technicians

testing batteries, charging systems, and starter circuits 31

Turn on critical electrical loads as specified by ABYC
Standard E-11, as shown in the worksheet opposite. After
a few seconds the EXP will prompt you to rev the engine
for 5 seconds with the loads on. The correct rpm level will
be shown in a graphic display similar to that shown for the
no-load test in photo 2 on page 29.

Next, turn off the loads and the engine.

The test results. In this case the system only lost 0.01 V
between the loaded and unloaded test, indicating that the
alternator charging system had no problem keeping up
with the loads. The minimum to look for is 0.5 V more than
the initial open-circuit voltage reading on the battery
before the alternator is even operating (i.e., with the
engine not running). The EXP-1000 will check this automat-
ically; thus the screen displays “no problems.”

The arrow keys allow you to scroll through a series of

results in bar graph format.

The results of the AC ripple test, showing peak-to-peak AC

voltage and a graph of the diode waveform.

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