Alternator Wiring to VE Argofet Isolator

[browntw.79]

Yesterday, after 11 months and 1,200 hours we pulled our Albin 36 out and ran a sea trial (drone photo below). Very happy overall with her performance. 😎👍 After returning from a two-hour run I noticed my start battery voltage was lower than normal (12.1V). I would have expected it to be full. I suspect it is something with my charging setup. I have installed a new 145-amp Delco 19si alternator on my Cummins 6BT engine. I have the alternator connected to a Victron Energy ARGOFET battery isolator (200A – 3 bank). I currently have it connected as shown below. My question is where do I connect the “Energize” terminal on the isolator? Connect it to the #1 terminal on the alternator. or does it connect to a 12V engine run source such as the fuel solenoid? I don’t want to incorrectly connect anything that could damage either device. Any insight would be appreciated.    

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[Rob Schepis]

Looks real good.  So you put the DVM’s on momentary switches?

I installed that same model Blue Seas DC panel in my personal boat a couple seasons back.  FYI – Last season I had a section of one of the strips of the LED backlights go out.  They sent a replacement strip at no charge.  Easy swap.

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[browntw.79]

Rob –

Thanks for the reference.  This is actually how I identified the issue.  After reading your article some time ago, I added a volt meter for my start, bow, and stern (all AGM) and my house which is LiFePO4.  I realize that voltage is only part of the picture, but it helped me identify that my start battery was not charging after a 2-hour trial.  All my boat’s systems are being redone which I know from engineering can create some diagnostic challenges.  After our first sea trial the other day I noticed the voltage on the start battery was lower than expected.  I suspected it was the alternator (new 19si for SBM) and the VE Argofet I had added.  It ended up being the missing connection on the Argofet.  After adding an engine 12V source to the energizer on the Argofet the batteries were all charged yesterday after a 5-hour trip to our boatyard for haul out.  

I appreciate the insight something as an inexpensive voltmeter can offer.  Thanks again to the whole SBMarine team has offered me.  

 

 

[Rob Schepis]

Thanks for posting your work and results.  How exactly were you measuring the state of charge at your different batteries/banks ?

Below is the article Tony referenced.  I cannot stress enough how important it is to know exactly what is going on directly at the individual battery banks whether you are charging, draining, isolating, combining, resting, etc.  Only then can you be 100% confident that everything is working as intended and meeting your needs.

Installing Digital Volt Meters (DVM) on Your Boat

 

 

[browntw.79]

Adding a 12V energizer wire from the fuel solenoid to the “energizer” terminal on the isolator worked perfectly yesterday.  We ran the boat on a five-hour trip to a boat yard for a haul out and the batteries were all in a great state of charge.  Thanks again for all the insights.

[Gene Fuller]

I believe this exact situation is covered in a Tony’s Tip.

How to Install a Diode Isolator with an Alternator

The “energize” terminal on the isolator is not directly connected to the alternator. The “energize” terminal is an input, not an output. It will not feed anything back to the alternator terminal #1.

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[Tony Athens]

Battery Charging –Alternators

IMO, absolutely  NOT…..

The right answer will come from a better understanding of your Fancy Vic Isolator gizmo ( I have zero–got a manual?)  combined with a DCV monitoring system that reads to .1 VDC accurately  for each battery bank individually  and  measures (+ to -)  BATTERY TERMINAL VOLTAGE (not buss bar or DC panel voltage) ..

No other DC voltage on the vessel really matters until you have that in place 

Without that. you are 100%  flying (charging) BLIND and that is IPPSO FACTO.   A good article was put together by Rob Schepis  for this web site a few yrs ago. He now has some yrs of experience on this system and maybe he’ll add some current input as to it real value

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[browntw.79]

Thanks, Tony.  I just want to be clear so I don’t mess up the wiring to the alternator connections.  Would the 12V from the fuel solenoid (early 6BT with Lucas fuel pump) be an appropriate “sensing” for terminal #1 on my 19si alternator?

[Tony Athens]

The #1 terminal on the alternator is the “sensing” terminal.. Unless it “sees” a positive voltage, the alternator WILL NOT turn on and start charging.  The regulator circuit of the alternator is controlled by what the sensing terminal “sees”..  There are very good pictures of this alternators wiring and connections on this web site

 

 

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[browntw.79]

Gene . . . thanks.  I was waffling between connecting it to the #1 terminal on the alternator (exciter terminal) or the 12V at the fuel solenoid.  I think I will try the fuel solenoid tomorrow unless someone provides different advice.  

[Gene Fuller]

The one-page installation manual seems pretty clear.

“The new Argofet isolators have a special current limited energize input that will power the B+ when the engine run/stop switch is closed.”

In other words this energize input needs to be connected to some place that is powered when the engine run switch is on and unpowered when the engine run switch is off.

The purpose of this input is to connect battery voltage back to the alternator to allow the alternator to start up. Otherwise the isolator blocks the voltage from the battery and the alternator may not start up into an “open” circuit.

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