12V alternator for D3 Volvo on Amel 54


Ian Fraser
 

We are slowly working through the rehabilitation of our recent purchase of an Amel 54. This community has been an invaluable source of great advice and I'm constantly amazed at the body of knowledge and cooperation amongst Amelians! Thank you.

Grateful if anyone can advise a source for a replacement 12V alternator for Volvo D3 on Amel 54 #009. It looks like the previous owner of our A54 replaced the original with an alternator that cannot be isolated from the bonding. In other words there's no negative terminal and the alternator picks up the -ve from a case connection. The previous owner bridged the -ve start solenoid and therefore defeated the 12V -ve isolation from bonding.

Any suggestion would be gratefully received.

Ian Fraser
Dreamtime
A54 #009


 

Ian,

I know this 54. You have a big job ahead of you. The original 12v alternator would have been attached to the engine by Volvo, and the isolation ground wired by Volvo France. But since there was nothing special about the 12v alternator, call your Volvo dealer with the model and serial number. They will be able to help you. Hopefully, important parts like C-Drive shafts and the AutoProp did not suffer too much electrolysis. 

You should check with Volvo, but I think that your D3 originally came with Volvo Penta Alternator part number 8676498. Here are some that match 8676498

Be sure to check that 8676498 is the correct number and that it is isolated ground.

Bill

CW Bill Rouse Amel Owners Yacht School
Address: 720 Winnie, Galveston Island, Texas 77550 
View My Training Calendar

On Wed, Oct 13, 2021 at 1:35 PM Ian Fraser <keyproperties@...> wrote:
We are slowly working through the rehabilitation of our recent purchase of an Amel 54. This community has been an invaluable source of great advice and I'm constantly amazed at the body of knowledge and cooperation amongst Amelians! Thank you.

Grateful if anyone can advise a source for a replacement 12V alternator for Volvo D3 on Amel 54 #009. It looks like the previous owner of our A54 replaced the original with an alternator that cannot be isolated from the bonding. In other words there's no negative terminal and the alternator picks up the -ve from a case connection. The previous owner bridged the -ve start solenoid and therefore defeated the 12V -ve isolation from bonding.

Any suggestion would be gratefully received.

Ian Fraser
Dreamtime
A54 #009


Bill Kinney
 

Ian,

Look around for these.  Alternators are very standardized.  Once you know the size (50 Amp), and the type of mounting bracket (not sure for your engine, but there are only a few choices and are easily distinguished with a few measurements) any one will do.  

A quality, name brand, 50 Amp isolated ground marine alternator shouldn't cost more than $350 (and that's on the VERY high end!).  The green paint Volvo puts on the alternators they buy and resell is the MOST EXPENSIVE green paint on the planet.

Bill Kinney
SM160, Harmonie
Annapolis, MD, USA


Scott SV Tengah
 

Ian,

When you say "the alternator picks up the -ve from a case connection", do you mean alternator case? If so, there's a small chance that the alternator is isolated. Did you check continuity between the alternator case and the engine block? If none exists, you're good to go.

I had trouble finding an "isolated" 12v alternator when I had to replace mine. The Volvo one I found was not isolated. We ended up modifying it ourselves to isolate it by drilling out the mounting bracket hole to allow for a delrin sleeve around the mounting bolt and also using a delrin washer between the alternator-side bracket and the engine-side bracket.

Then we connected the always-on 12v battery negative to one of the bolts on the alternator case. I have verified with a multimeter that no continuity exists between the alternator and bonding system and that the alternator supplies charging current as intended.

There is, of course, the entire ground isolation solenoid system, which I hope your boat still has.

Note that your masse+/- light is useless in looking for 12v bonding faults as it's designed to look for 24v faults.

At the end of the day, I will roughly quote Olivier when he said that a non-isolated alternator is not ideal, but it's not the end of the world as many other boats have their 12v system connected to bonding. Fix it if you can, but don't panic if you can't right away.

--
Scott 
2007 A54 #69
SV Tengah
http://www.svtengah.com


Ian Fraser
 

Excellent Bill. Thanks for the advice…..It’s the isolated ground that seems to be the issue.

On 13 Oct 2021, at 22:46, Bill Kinney <cruisingconsulting@...> wrote:

Ian,

Look around for these.  Alternators are very standardized.  Once you know the size (50 Amp), and the type of mounting bracket (not sure for your engine, but there are only a few choices and are easily distinguished with a few measurements) any one will do.  

A quality, name brand, 50 Amp isolated ground marine alternator shouldn't cost more than $350 (and that's on the VERY high end!).  The green paint Volvo puts on the alternators they buy and resell is the MOST EXPENSIVE green paint on the planet.

Bill Kinney
SM160, Harmonie
Annapolis, MD, USA


Ian Fraser
 

Scott,

This is excellent advice, and I suspect the previous owner hoped that Olivier’s advice was good! I will see if the alternator I have can be isolated from ground!

Thank you.

Ian

On 14 Oct 2021, at 06:14, Scott SV Tengah <Scott.nguyen@...> wrote:

Ian,

When you say "the alternator picks up the -ve from a case connection", do you mean alternator case? If so, there's a small chance that the alternator is isolated. Did you check continuity between the alternator case and the engine block? If none exists, you're good to go.

I had trouble finding an "isolated" 12v alternator when I had to replace mine. The Volvo one I found was not isolated. We ended up modifying it ourselves to isolate it by drilling out the mounting bracket hole to allow for a delrin sleeve around the mounting bolt and also using a delrin washer between the alternator-side bracket and the engine-side bracket.

Then we connected the always-on 12v battery negative to one of the bolts on the alternator case. I have verified with a multimeter that no continuity exists between the alternator and bonding system and that the alternator supplies charging current as intended.

There is, of course, the entire ground isolation solenoid system, which I hope your boat still has.

Note that your masse+/- light is useless in looking for 12v bonding faults as it's designed to look for 24v faults.

At the end of the day, I will roughly quote Olivier when he said that a non-isolated alternator is not ideal, but it's not the end of the world as many other boats have their 12v system connected to bonding. Fix it if you can, but don't panic if you can't right away.

--
Scott 
2007 A54 #69
SV Tengah
http://www.svtengah.com


Dean Gillies
 

Ian,
I have recently replaced my alternator with the (expensive) Volvo numbered model. I had to modify (ie machine) the alternator mountings to accept the delrin 'sleeves' that Scott mentioned. I suspect these sleeves were installed by Amel. So be aware that the Volvo numbered alternator does not just fit without modification, even if you do have those sleeves to hand.
Good luck.
Dean
SV STELLA
A54-154
Currently in Fisterra, Spain

Sent from my iPhone X


Ian Fraser
 

Thanks Dean. It certainly looks like this is a common issue with trying to find an isolated ground alternator that fits on the D3……seems the Volvo ones needed to be “modified”.

On 16 Oct 2021, at 02:38, Dean Gillies <stella@soundthinking.com.au> wrote:

Ian,
I have recently replaced my alternator with the (expensive) Volvo numbered model. I had to modify (ie machine) the alternator mountings to accept the delrin 'sleeves' that Scott mentioned. I suspect these sleeves were installed by Amel. So be aware that the Volvo numbered alternator does not just fit without modification, even if you do have those sleeves to hand.
Good luck.
Dean
SV STELLA
A54-154
Currently in Fisterra, Spain

Sent from my iPhone X