"Bob McMillan" wrote in message
...
Good morning. Maybe someone can help me with a perplexing problem before
I
have to turn it over to an auto/boat electrician. The boat is a Buccaneer
470 with an 82 Evinrude 90hp V4. I use it trolling for Trout on Lake
Toupo - running the main engine about 30 minutes a day, and on the
trolling
motor (no charging coil) for about five hours a day. The ignition is
always
switched off when trolling, and the fish-finder draws 350mA. The battery
is
new (2nd one I have purchased) and has 44 amp hour reserve capacity)
The symptom was a flat battery after three days connected to the main
terminals. I had an isolating switch installed and used it at night to
isloate the battery. No difference - flat battery again after four days.
So I put a multi-meter in series with main positive terminal and I found
that there is a 32mA current drain with everything turned off. With the
battery isolator switch on the off position, no current drain. The boat
shop checked the rectifier and charge current - reported as all OK. (?)
Then I began to disconnect all the electric service wires at the battery
one
by one - fish finder, nav lights and ignition. No effect on current
drain.
It was the main wire to the engine (presumably the ignition/charge wire)
that was drawing the current. Fishing around in the engine (I am no
expert)
I could not find any spurious voltage. The main (large diameter) red to
the
starter solenoid was live, as was one smaller red wire to a centre relay
connection - but that was it. I then checked all the metal fittings,
engine
casing, boarding ladder, etc, in case there was a short somewhere - no
result.

So, sorry about the long-winded preamble, but what should I check next??

Thanks

Bob McMillan
New Zealand

If, when the isolator switch is operative, the ammeter shows a nil current
drain, and the alernator is charging as specified, then the battery must be
faulty. If you are taking out more current in normal use than you are
putting back in, then either the charging circuit is faulty or your usage is
to blame.

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