[C38] Alternator and charging

Steve Smolinske SSmolinske at rainierrubber.com
Mon Jul 6 02:03:43 EDT 2009


Conclusion for everyone on this item,  I took Tom's advice and what a difference in the system.  I ended up having the alternator and starter tested and rebuilt ($125) new brushes, regulator and contacts.  When hooking it back up I ran current from the alternator directly to the starter then on to the battery switch.  The wires that use to lead the current up to the ampmeter and then back to the starter (red and orange #10) one was abandonded and the other powers the new voltmeter with an inline fuse.   I also replaced the battery switch with Blue Seas newer switch that completly isolates the house and start banks with the exception of emergency combine, just one choice on or off for normal operation, no more 1, 2 or 1&2 to confuse the admiral.  It also turns out that the problem most likely was an incorrectly installed ACR,  there are two important small wires that allow the ACR to sense both banks.  Even though the ACR wiring was probably the culprit it is a nice feeling after tearing things apart to realize that all that current from the alternator is no longer going through two undersized wires and a suspect wire harness but instead is being carried by a battery cable to the batteries. 
 
Steve 
Peregrine #312
Seattle

________________________________

From: listserve-bounces at catalina38.org on behalf of Tom T.
Sent: Mon 6/29/2009 3:27 PM
To: Catalina 38 Listserve
Subject: Re: [C38] Alternator and charging


 
 
Hello Steve,
 
You are correct.  The 30 amp fuse in your charging circuit is too small to carry the load if the batteries are discharged or you are running other high load applications.  I expect they may be using a small fuse to try to reduce the maximum load on the wiring harness which has been a problem in the past.
 
To carry a high amperage load to your engine control panel is not only a lot of electrical loss but it can be dangerous if your harness connections are corroded.  There have been many original engine control harnesses burned up because of the high load on the amp meter wires in that harness.
 
The amp meter isn't needed anyway.  You can have an amp meter showing a lot of amps but if your battery bank is shorted, you will only be creating heat on the harness and load on your engine but a shorted battery will never charge with the amp meter giving you a false sense of security.   A volt meter gives a better idea of your charging and battery conditions.
 
A more practical solution to the amp meter is to replace the original amp meter with a marine grade volt meter.  To do this, you run the output of the alternator directly to your battery banks and use the original wires to the amp meter to feed a new volt meter.  You can run the feed to the volt meter from the positive side of the starter solenoid since it is very close to the alternator making a very easy conversion.
 
The volt meter conversion is a very good and highly recommended upgrade.  It will make your boat safer and your alternator will perform better because more output will go to the battery bank instead of wasted in heat loss in the harness and possible faulty connectors.
 
Fuse the wire that you run from the solenoid to the new volt meter.  There will be very little current on that wire now so even a small fuse like 5 amps will do fine.  The fuse should be very close to the alternator for safety.  
 
It has been a long time since I made this modification on my boat but I believe the harness wire used for the volt meter conversion is an orange wire.  I wrote an article for Mainsheet several years ago about this conversion but I don't remember what year or month it was but I'm sure I can find a draft copy in my archives if you need it, just let me know and I'll look for it.
 
Good luck,
 
Tom Troncalli
Renata (Hull #95)

	----- Original Message ----- 
	From: Steve Smolinske <mailto:SSmolinske at rainierrubber.com>  
	To: Catalina 38 Listserve <mailto:listserve at catalina38.org> 
	Sent: 6/29/2009 4:35:25 PM 
	Subject: [C38] Alternator and charging

	
	Tom T, I'm hoping you can add some insight on this.   I suspected my system wasn't charging so I took the alternator and starter off and had them both tested, they are fine, and since there off I took the precaution to have the regulator, brushes and contacts replaced.  Going over the wiring diagram for the M30 They call out #10 wire with a 30 amp fuse inline from the amp meter to the Starter Solenoid.  Knowing that a regulator varies charge based on battery condition/charge and rpm isn't a 30 amp fuse undersized, and why a fuse anyway, shouldn't the wire be sized correctly to handle the highest load the system would see.   
	 
	 
	Steve Smolinske
	President
	 
	4M Company, Inc.
	15660 Nelson Place South
	Seattle, WA  98188
	425-227-4500
	www.rainierrubber.com <http://www.rainierrubber.com/> 
	
	 
	The information contained in this email may be confidential and/or proprietary in nature and is intended for the recipient of the email only.  Please treat all information contained in this and any communication with the 4M Company as such.  Thank you.
	 
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