Where is the battery isolator?

Status
Not open for further replies.
Feb 15, 2007
19
Hunter 40.5 Oriental
Hunter references a battery isolator - does anyone know where it is on a 1997 40.5?
 

Rick D

.
Jun 14, 2008
7,182
Hunter Legend 40.5 Shoreline Marina Long Beach CA
Where Mine Is

...on a 1994 is in the general area of the alternator, mounted on the port mid/upper forward side of the engine compartment.
 
Feb 15, 2007
19
Hunter 40.5 Oriental
Thanks, but not there

Rick, thanks for the quick reply, but ours is not there! Just trying to figure out where they put it....no-where obvious so far!
 
Feb 15, 2007
19
Hunter 40.5 Oriental
Seems that the isolator is really just the combiner...

After much diagnosis - the "isolator" must just be the combiner knob....
 
Feb 15, 2007
19
Hunter 40.5 Oriental
Our boat has a solenoid to the left of the battery switch....we were assuming the the battery switch (what I'm calling the "combiner") acts as the isolator.
 

Rick D

.
Jun 14, 2008
7,182
Hunter Legend 40.5 Shoreline Marina Long Beach CA
I Don't Think So

What I was referring to as an isolator is, I think, actually a 'combining relay' which I think combines the house and start banks when there is 13 volts in and disconnects when less. But that is with a very shoddy memory. Anyhow, that's where mine is. On Don's photo, it is about 8" above and to the right of the alternator, on the wall.
 
Feb 15, 2007
19
Hunter 40.5 Oriental
Apparently no two boats are alike! I think we've got it figured out - just don't know why the documentation refers to "the isolator" and then fails to label it at all. Thanks for your help!
 
Feb 10, 2007
213
Hunter Legend 40.5 Coconut Grove, FL
Follow the positive wire out from the alternator and if there is an isolator, it will end there, with two more cables, one from the house, and one from the start.
Here is mine:
 

Attachments

Sep 25, 2008
7,337
Alden 50 Sarasota, Florida
Our boat has a solenoid to the left of the battery switch....we were assuming the the battery switch (what I'm calling the "combiner") acts as the isolator.
Karen

If it isn't clear, the solenoid is a starter relay. The battery switch is just that and the isolator will, depending upon which one, look like a box with three wires such as that in Marco's picture and wired as he described. Hope you already had it figured out.
 
Feb 15, 2007
19
Hunter 40.5 Oriental
OK, here's a photo I just snapped - there simply isn't a "box" as you show anywhere that I can find on this boat!
 

Attachments

Sep 25, 2008
7,337
Alden 50 Sarasota, Florida
It's unlikely there is none - there would ordinarily be some way to ensure both the start and house banks are charged by the alternator which would necessitate some form of interconnection via an isolator, combiner, ACR relay, etc.
Is that a Volvo engine?
 
Dec 5, 2003
204
Hunter 420 Punta Gorda, FL
The solenoid is the combner

On our boat there is a solenoid that parallels the house and start batteries when the key is in the run position. You probably will hear a click when you turn on the key to start the engine. So every time you run the engine it combines the start and house batteries. When you are charging from shore power you either have an extra terminal (echo charge) on the charger that goes to the engine battery or nothing (which is what my boat has, no need to continually charge the start battery).

You will probably see that the two heavy terminals on the solenoid go to the house and engine battery positive leads.
 
Jul 20, 2005
2,422
Whitby 55 Kemah, Tx
On our boat there is a solenoid that parallels the house and start batteries when the key is in the run position. You probably will hear a click when you turn on the key to start the engine. So every time you run the engine it combines the start and house batteries. When you are charging from shore power you either have an extra terminal (echo charge) on the charger that goes to the engine battery or nothing (which is what my boat has, no need to continually charge the start battery).

You will probably see that the two heavy terminals on the solenoid go to the house and engine battery positive leads.

Same on my boat and what I like about it is, you can get replacement anywhere.
 

jorum3

.
Dec 23, 2008
2
Hunter 40.5 Vandemere
We have a 1996 40.5 with the Volvo engine and have the same relay. As Rick & Bill wrote, it combines the output of the altenator once the engine starts. It acts like a combiner and when the engine is off it allows the solar panel to charge the starting battery without trying to charge the house batteries.
 
May 10, 2004
113
Hunter 340 Bremerton, WA up from Woodland
I am wondering if the "isolator" you refer to in the original post is really the galvanic isolator rather than a battery isolator?
 
Jun 14, 2009
3
Hunter 40.5 Green Coves Springs, FL
Battery combining relay

The grey relay shown in the picture by karenmccraw combines (parallels) the house and starting battery when the engine switch is on. Mine went bad and I replaced it. I also replaced the ON/OFF starting battery switch with a 1/2/BOTH battery switch so that I can manually parallel the batteries.
I have 330 W of solar power with a controller that puts 10% into the starting battery and 90% into the house battery. The starting battery stays fully charged.
 
Apr 15, 2009
302
C&C 30 Annapolis
isolator

Hunter usually hid the "galvanic isolator" behind the DC breaker panel by the nav station. It will most likely have a sticker on it labeling it as such. This is not to be confused with external voltage regulators for the alternator or battery combiners.
 
Status
Not open for further replies.