[C38] Electrical System Troubleshooting

[Jay Sorensen]

G'Day All,

We've owned Broad Reach, a 1985 C38 with a fairly standard electrical
system for about 6 years.  I've diagnosed several electrical issues to date
but this one is something a little different.  I replaced our aging
starting battery with an AGM group 24 battery on Saturday.  During our
outing on Sunday our engine started fine with Battery #1 (AGM starting
battery), but when attempting to turn on any system via the panel there was
no power.  Try battery #2, no power.  Try "Both", no power.  Check the
battery voltage using the panel voltmeter, no power shown at the voltmeter
while the engine was running.  Come back to the dock, stop the engine,
voltmeter shows 12+ volts power at the panel from both batteries at the
voltmeter.  With shore power on the panel will power up when jumping to the
battery charger cables running to the battery switch.  Panel will not power
up when powered directly to either main battery cable.  Battery cables
showing 0.1-0.2 Ohms of resistance but I'm not sure if that is normal.
Turned off shore power, started motor again with switch to #1, started
fine, alternator is charging fine.  Weird.  Next I'll try jumping directly
to the batteries and bypass the cables but it seems odd that both cables
are having issues when they show good voltage.  Frustrating!  Any
suggestions??  Maybe something where the engine electrical system interacts
with the system power panel inputs??  Many Thanks!...............Jay
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