main@AmelYachtOwners.groups.io | Still have current when ignition is off

720 Winnie, Galveston Island, Texas 77550

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On Wed, Jul 13, 2022 at 6:09 AM CARINA HAMMARLUND <syultimo@...> wrote:

Hi
we have a current of 25,9 V to our heat sensors at both Onan generator and to the main engine, even though we turned off the ignition key?

is this normal or what do we need to check?

very grateful for your feedback
--
Carina
SV Ultimo
Amel 54 No 165

CARINA HAMMARLUND

#64517

Hi Bill

we put the plus cable from the multimeter, on top of the sensors we have two cables and it doesn’t matter which one we choose or which sensor we measure on (heat sensor, exhaust sensor on the pipe or water sensor or the oil pressure sensor) the minus we take from the frame of the main engine.
we have had no one onboard installing anything (except changed the AIS).

if we turn the controll swith on the panel for the bounding we have a clear red signal on minus but not on the plus.

--
Carina
SV Ultimo
Amel 54 No 165

CW Bill Rouse

#64518

The red signal (-) tells you that the bonding system is connected to the house bank 24 volts. In the case where nothing has ever been modified on an A54 this can be:

Leaking seal in a macerator pump can show - or +. It is easy to check one at a time by removing the yellow/green wire on the macerator pump.
The Mastervolt alternator body is in contact with the engine block. This happens because one of the nylon insulators or washers has cracked or is missing. If your Volvo was serviced by a Volvo mechanic, when tightening or replacing the belt, will remove these and throw them away.

The house bank 24-volt has zero connections to the Onan unless someone has connected the 12v and 24v negatives. Sometimes this connection is part of installing a Victron charger with dual charge zones. Internally, Victron has a connection between the 2 negatives.

Of course, there are many other possibilities, I am just giving you the most common.

Bill

CW Bill Rouse Amel Owners Yacht School

720 Winnie, Galveston Island, Texas 77550

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On Wed, Jul 13, 2022 at 11:18 AM CARINA HAMMARLUND <syultimo@...> wrote:

Hi Bill

we put the plus cable from the multimeter, on top of the sensors we have two cables and it doesn’t matter which one we choose or which sensor we measure on (heat sensor, exhaust sensor on the pipe or water sensor or the oil pressure sensor) the minus we take from the frame of the main engine.
we have had no one onboard installing anything (except changed the AIS).

if we turn the controll swith on the panel for the bounding we have a clear red signal on minus but not on the plus.

--
Carina
SV Ultimo
Amel 54 No 165

CARINA HAMMARLUND

#64521

Thank you we will try the Maccarator lead tomorrow morning since we do plan to change one maccarator due to a small leak!
We have a VW engine in our A54, do you think it’s different in regards to your suggestions about the Volvo?

One again thank you and we will continue our search tomorrow.
--
Carina
SV Ultimo
Amel 54 No 165

CW Bill Rouse

#64522

When a macerator begins to leak, the bonding is usually compromised.

I think that if your 24-volt alternator is the Mastervolt 110, it must be mechanically isolated from the block.

CW Bill Rouse Amel Owners Yacht School

720 Winnie, Galveston Island, Texas 77550

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On Wed, Jul 13, 2022 at 12:41 PM CARINA HAMMARLUND <syultimo@...> wrote:

Thank you we will try the Maccarator lead tomorrow morning since we do plan to change one maccarator due to a small leak!
We have a VW engine in our A54, do you think it’s different in regards to your suggestions about the Volvo?

One again thank you and we will continue our search tomorrow.
--
Carina
SV Ultimo
Amel 54 No 165

CARINA HAMMARLUND

#64531

Hi
Our alternator originally on the VW is a ISKRA truck alternator 28V/110 amp. Just good to know if someone else with a VW engine get some problem….
--
Carina
SV Ultimo
Amel 54 No 165

CARINA HAMMARLUND

#64532

Hi again
My mistake, today we have a Mahle 28v/110 amp.
ISKRA was the original alternator that we changed in Tahiti after it started burning during motoring …
--
Carina
SV Ultimo
Amel 54 No 165

CW Bill Rouse

#64538

Exactly as I thought might be true. Someone has worked on an isolated component.

I believe that you will find that Amel insulated the alternator from its mounts, therefore isolating it mechanically from the engine. It is highly probable the person mounting the new alternator either did not know about this or ignored it. Check to see if there is continuity between the alternator chassis and the engine block.

CW Bill Rouse Amel Owners Yacht School

720 Winnie, Galveston Island, Texas 77550

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On Thu, Jul 14, 2022 at 3:37 AM CARINA HAMMARLUND <syultimo@...> wrote:

Hi again
My mistake, today we have a Mahle 28v/110 amp.
ISKRA was the original alternator that we changed in Tahiti after it started burning during motoring …
--
Carina
SV Ultimo
Amel 54 No 165

Eric Freedman

#64547

The negative post of most alternators that are isolated are with a plastic looking washer. Check the continuity with all wire removeds from the negative post of the alternator to the alternator body.

Fair Winds

Eric

Kimberlite Amel Super Maramu #376

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From: main@AmelYachtOwners.groups.io On Behalf Of CW Bill Rouse
Sent: Thursday, July 14, 2022 9:08 AM
To: main@AmelYachtOwners.groups.io Notification <main@amelyachtowners.groups.io>
Subject: Re: [AmelYachtOwners] Still have current when ignition is off

Exactly as I thought might be true. Someone has worked on an isolated component.

I believe that you will find that Amel insulated the alternator from its mounts, therefore isolating it mechanically from the engine. It is highly probable the person mounting the new alternator either did not know about this or ignored it. Check to see if there is continuity between the alternator chassis and the engine block.

Image removed by sender.

CW Bill Rouse Amel Owners Yacht School

720 Winnie, Galveston Island, Texas 77550