Why no Isolator on 2001 400DB with Cummins?

[ZZ13]

In debugging a potential alternator issue I traced all the 12V wiring on my boat. I found a big difference in the wiring diagram and the actual wiring. The diagram shows an isolator between the alternators/battery charger and the batteries. Each engine's battery bank would take two separate paths for the + cable. The first path would be to the switch/breaker panel then to the emergency start switch and then on to the starter, for starting the engine. The second path would be to the isolator and then from there to the battery charger and the alternator, for charging the battery bank. But in reality, there is no isolator. Each engine's battery bank only takes one path. From the battery to the switch/breaker panel, on to the emergency start switch, on to the starter and then on to the alternator. The battery charger is just a point to point wire from the charger to the battery bank.

So, why is there not an isolator even though the diesel wiring diagram for the boat says there should be one? I did find a three lug isolator (one in - two outs) bolted to the same panel as the battery charger, but it is not connected to anything.

 

[ZZ13]

For those of you waiting anxiously for an answer on this, I emailed the question to Sea Ray. Answer is that they used an isolator up through 1998 on this model because the converter used required it. They then switched converters and didn't need the isolator anymore.

Happy boating!

 

[PMC]

For those of you waiting anxiously for an answer on this, I emailed the question to Sea Ray. Answer is that they used an isolator up through 1998 on this model because the converter used required it. They then switched converters and didn't need the isolator anymore.

Happy boating!

I like it, less parts to break. thanks for the info!!

 

[ttmott]

Mine has no isolator either. I did however put ACR's across the three battery banks so should any one of the alternators fail all the banks will still charge; it's a failure backup thing....

I wish Sea Ray would issue accurate schematics for the boats; there are a host of inaccuracies with the ones for my boat. Makes it difficult to diag. a problem on the water.

 

[Art]

For those of you waiting anxiously for an answer on this, I emailed the question to Sea Ray. Answer is that they used an isolator up through 1998 on this model because the converter used required it. They then switched converters and didn't need the isolator anymore.

So when underway and genset is running is it best practice to shutoff the converter?

 

[ZZ13]

So when underway and genset is running is it best practice to shutoff the converter?

I am now. I thought I had an isolator protecting the alternator and battery charger from working at the same time. But now that I don't I am turning the converter off before I start the boat.

 

[ttmott]

I am now. I thought I had an isolator protecting the alternator and battery charger from working at the same time. But now that I don't I am turning the converter off before I start the boat.

Technically, it doesn't matter how many "chargers" are connected to and charging a battery; they will all work based upon the charge level in the batteries. The isolators, which were required with the old style chargers simply prevent a faulty battery bank or alternator from dragging the whole system down yet any charging source will charge all the banks. The more modern ACR's (Automatic Charging Relay) allow any charging source to charge any battery bank and there is no voltage drop which was a problem with the isolators. My charger is always on regardless engines running or not.

 

[ttmott]

This is a pretty good link to info http://www.bluesea.com/resources/1366/Automatic_Charging_Relay_%5BACR%5D_Explained