Re: [Amel Yacht Owners] Alternator and Masse leak detector



Your problem may be an indication of something much more serious.

How long have you owned this Amel 54? Has there been an engine change, or any sensors changed?

When Amel installed the Volvo D3-110, it had been modified to be Isolated Ground by Volvo France. If you ask any Volvo dealer to check the serial number for such a modification, it will not show up on Volvos database. In fact, it is difficult to find any Volvo record of this modification which occurred with 100% of all D3s installed when the 54 was built by Amel. 

I believe that your Isolated Ground has been defeated because of either:
  1. Engine change
  2. Non-Isolated Ground sensors or switches installed replacing original ones
  3. Some other modification made by some "expert" which has defeated the Non-Isolated Ground
Yes, if any of the above are true, when you disconnect the 24VDC Negative from the 24VDC Alternator, you will remove the fault indicated on the Bonding test circuit.

I consider this issue serious and you should seek expert help. A defeated Isolated Ground has been the cause of ruined C-Drives and other serious issues. Until you have this resolved, you should add a propeller zinc, although that will not completely protect things.


CW Bill Rouse
Admiral, Texas Navy
Commander Emeritus

Amel School
720 Winnie St
Galveston Island, TX 77550

+1(832) 380-4970

On Tue, Jun 19, 2018 at 5:23 AM Nick Newington ngtnewington@... [amelyachtowners] <amelyachtowners@...> wrote:

Hi Alan,

I have had an electrician check the boat for me and I asked him to look into the -ve leak and to then try some diagnosis.

This is his reply  "I checked the leak controller, it shows a leak in negativ. I tried several things like bilge pump but nothing changed. When I dismantled the negativ from the 24 V alternator, the leak light went off. So, the problem might be the alternator or somewhere at the engine.”

So I reckon that this would suggest a fault on the 24v alternator or some kind of leak to the bonding system from the engine.


On 19 Jun 2018, at 02:18, divanz620@... [amelyachtowners] <amelyachtowners@...> wrote:

Hi Nick,

We have a NEXT STEP-2 reg ...there is a file in the Files section showing how I did it

The reg in the Leece  Neville alt is not designed to charge deep cycle batteries.
Keeping the voltage always at 28.8V will eventually kill your AGM batteries. They need a bulk, absorption, float regimen if they are to be cared for properly.

We have 
600W solar panels and  a Victron MPPT controller
Leece Neville 175A engine alt with Next Step-2 reg
Victron Skyalla 100A charger
Promariner 30A charger

and they are all set to the same absorption and float voltages.

Diodes fail open, I don't think that can be the cause of your problem.

Somewhere on some device that has both 24VDC feed AND a connection to the bonding system, there is a connection between -ve and the bonding connection...and it may not be a metal to metal contact , frequently it is through the sea water. 

Good Luck
Elyse SM437  Yasawa-i-rara

Join to automatically receive all group messages.