[C38] Universal 5424 Charging problems

Jim and Barbara williams at barbara-james.com
Mon Oct 10 07:56:49 EDT 2005


As always, Tom's advice is right on target.  I just want to add that my
instrument package (NX-2) tells me the battery voltage, so I installed a
shunt-type ammeter in the engine panel.  That makes both critical pieces of
information available to me in the cockpit.  If you haven't upgraded your
instruments yet, you might want to put the voltmeter feature on your "very
nice to have" list.

Jim Williams
C38 #180
Checks in the Mail
Norfolk, VA

-----Original Message-----
From: Listserve-bounces at catalina38.org
[mailto:Listserve-bounces at catalina38.org] On Behalf Of Tom T.
Sent: Sunday, October 09, 2005 7:50 PM
To: Catalina 38 Listserve
Subject: Re: [C38] Universal 5424 Charging problems


I don't have the specs on the original alternator with me because my boat is
about 500 miles from me and my alternator notes are on the boat.

Before you give up on your original alternator, first check to see if the
electrical power is even getting to your battery.  The original wiring
called for the alternator to feed the cockpit engine control harness through
a couple of wiring plugs in the harness, through a direct feed amp meter,
and back through the same harness and plugs and finally to the battery back.

With the original harness, any of the in-line harness plugs could corrode
and even the amp meter itself could corrode making an open or high
resistance circuit.  Because of the long harness length, the original
harness would lose alternator power even if all wiring plugs and amp meter
were perfect which is seldom the case.

An upgrade to the original system, if you have not done so yet, is to run
the alternator output feed directly to the battery bank and either convert
the amp meter on the engine control panel to a voltmeter or a shunt operated
amp meter which doesn't require the entire output of the alternator to feed
through it on the long distance to the control panel and back.  I prefer the
voltmeter because it tells the state of charge.  If a battery shorts, an amp
meter will give a false sense of security because it may show a high rate of
charge when all you are doing is cooking a shorted battery which will not
take a charge.  Neither the modern shunt type ampmeter or voltmeter take any
significant amperage back to the cockpit panel making both a much safer and
more reliable solution.

An easy way to check if the above original harness is your problem is to
remove the wire on the alternator output terminal and make a heavy 10 Ga or
larger wire to replace it.  With the new wire go directly from the output
terminal to the battery bank.  If your battery bank charges with the new
jumper cable, you are a prime candidate for the upgrade harness and meter

I'm sure I can find a copy of the upgrade information that was posted in
Mainsheet if you need to make the upgrade.

If this jumper feed cable doesn't correct your charging problems, you have
another charging system you can use.  You can charge your new alternator on
Vi$a, Ma$tercard, etc.

Your original 5424 alternator was probably a Motorola with the Japanese
mount dimensions and there are many alternators that will fit without paying
the ransom price of the Universal replacement as Mark and others
have correctly reported.   The only problem is that the new alternator
needs to have a tachometer pickup coil so it will have to be from a diesel

Tom Troncalli
The Renata #95
St. Pete, Fla

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