Reply
 
Thread Tools Display Modes
 
Old 10-10-2016, 10:27 PM   #1
Member
 
City: Huntington Beach, CA
Country: US
Vessel Name: Great Escape
Vessel Model: 1981 Californian
Join Date: May 2012
Posts: 14
Battery Isolator

I have twin Perkins 4-236 in my boat. I use one 4D starting battery to start both engines. This battery is charged by the port engine. The starboard engine charges the house bank. I have a battery switch that is wired to put all batteries on line for starting if needed. When all batteries are on line both alternators are charging all the batteries. I have been running with all batteries on line after starting. Yesterday I found that the alternator on the port engine was very hot when running. All batteries were on line. I think I blew a diode. I wonder since both alts are charging and not isolated could I be putting a strain on the alternators?
__________________
Advertisement

Stu-L is offline   Reply With Quote
Old 10-10-2016, 11:59 PM   #2
Guru
 
Brooksie's Avatar
 
City: Cape Cod, MA
Country: USA
Vessel Name: Island Seeker
Vessel Model: Willard 36 Sedan
Join Date: Oct 2007
Posts: 880
Usually not a good idea to connect two alternators together. Tha main reason being that one regulator with "argue" with the other. This can cause several problems including only one alternator doing all the work. This may be why only one of yours was hot to the touch.
I would try leaving the two systems separated for a while to be sure all is well with each system.

You should not move your 1,2,both switch while the engine is running, that will pop a diode. Some switches have a field disconnect to allow this but it can't disconnect the fields from two alternators.
__________________

Brooksie is offline   Reply With Quote
Old 10-11-2016, 12:03 AM   #3
Guru
 
O C Diver's Avatar
 
City: Fort Myers, FL... Summers in Crisfield, MD
Country: USA
Vessel Name: Slow Hand
Vessel Model: Cherubini Independence 45
Join Date: Dec 2010
Posts: 3,517
Unless you have an external 3 stage regulator, the alternators are designed to handle the load and moderately recharge the batteries. Would ask an alternator repair facility to trouble shoot the alternator. If the regulator became faulty, it may have had the alternator running at too high an amperage output which over heated it.

Ted
__________________
I'm tired of fast moves, I've got a slow groove, on my mind.....
I want to spend some time, Not come and go in a heated rush.....
"Slow Hand" by The Pointer Sisters
O C Diver is offline   Reply With Quote
Old 10-11-2016, 07:26 AM   #4
Guru
 
City: Hampton Va Back River
Country: United States
Join Date: Jan 2016
Posts: 779
I have been running my Delco 12SI alternators combined outputs for years with no troubles at all. It helps unload the alternator charging the 2 house batteries while the other loafs charging a single start battery. I put a continuous duty relay between the banks with a manual switch run off the fuel pump relay signaled from alternator the charges the single start battery.

I know it works as the amp gauge on one side falls, and the amp gauge on the other side rises when joined.

one time, I burnt a belt since one alternator was charging 2 house batteries putting out 60 AMPS and it was too loose. Letting both share the load is good idea, at least for ME. Whether it works for others, I can not say. Everyone has their own opinion about things.
sdowney717 is online now   Reply With Quote
Old 10-11-2016, 10:20 AM   #5
Guru
 
Brooksie's Avatar
 
City: Cape Cod, MA
Country: USA
Vessel Name: Island Seeker
Vessel Model: Willard 36 Sedan
Join Date: Oct 2007
Posts: 880
AmplePower relates some (but not all) problems with connecting 2 alternators together.

Two Engine/Alternator System
Brooksie is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





All times are GMT -5. The time now is 08:43 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2016, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012