24VDC to 12VDC converters: 0V connections


Sv Garulfo
 

Hi all,

On GARULFO, and I suspect on other A54s and maybe SM, there are three 24VDC to 12VDC converters, marked “permanent”, “hydra/iscan v90” and “VHF icom”.

Of those, only the “permanent” one has the input +0V and the output +0V posts connected. 

Does anyone know why that is?
Why shouldn’t the other 2 be the same?

In one pic:



Thanks


Best,


Thomas
GARULFO 
A54-122
Tahiti 




Rudolf Waldispuehl
 

Hi Thomas

 

On WASABI we have the same setup, except that there is a separate “Permanent ON/OFF” Switch under the converter (see picture).

I suppose you have another ON/OFF configuration on the Permanent and therefore they bridged the +0 on input and output.

Probably GARULFO do not have a ON/OFF Switch for the Converter Input and therefore the bridge makes your converter permanent as permanent 😉

The other 2 converter are just switched on when you push the green “INSTRUMENTS” button at the chart table next to the window.

 

Best and fair winds

Ruedi,

WASABI , Amel-54 #55

 

Von: "main@AmelYachtOwners.groups.io" <main@AmelYachtOwners.groups.io> im Auftrag von Sv Garulfo <svgarulfo@...>
Antworten an: "main@AmelYachtOwners.groups.io" <main@AmelYachtOwners.groups.io>
Datum: Sonntag, 27. Juni 2021 um 01:44
An: "main@AmelYachtOwners.groups.io" <main@amelyachtowners.groups.io>
Betreff: [AmelYachtOwners] 24VDC to 12VDC converters: 0V connections

 

Hi all,

 

On GARULFO, and I suspect on other A54s and maybe SM, there are three 24VDC to 12VDC converters, marked “permanent”, “hydra/iscan v90” and “VHF icom”.

 

Of those, only the “permanent” one has the input +0V and the output +0V posts connected. 

 

Does anyone know why that is?

Why shouldn’t the other 2 be the same?

 

In one pic:

 

 

 

Thanks

 

 

Best,

 

 

Thomas

GARULFO 

A54-122

Tahiti 

 

 

 


Arno Luijten
 

My guess is that these are isolated converters. So the input and output are not galvanically connected. This is typically required for radio transmitter equipment to prevent ground loops. This is where you can get all kinds of funny effects because of impedances of equipement relative to the minus/ground lead. Another example is NEMA-2000 supply that (officially) requires a isolated ground as well, so for this you need to use an isolated converter.

It may be they found a problem with some devices not having a ground connected to the battery ground and therefore had to connect the two 0V lines together.

Regards,

Arno Luijten,
SV Luna,
A54-121


Sv Garulfo
 

Thanks Ruedi 

We also have an on/off switch for the permanent, but Amel relocated it behind the wooden panel on the starboard side of the chart table. Not sure why, it’s not easier/more difficult to access there...

Cheers

Thomas 
GARULFO 
A54-122
Tahiti 

On 27 Jun 2021, at 09:58, Rudolf Waldispuehl <Rudolf@...> wrote:

Hi Thomas

 

On WASABI we have the same setup, except that there is a separate “Permanent ON/OFF” Switch under the converter (see picture).

I suppose you have another ON/OFF configuration on the Permanent and therefore they bridged the +0 on input and output.

Probably GARULFO do not have a ON/OFF Switch for the Converter Input and therefore the bridge makes your converter permanent as permanent 😉

The other 2 converter are just switched on when you push the green “INSTRUMENTS” button at the chart table next to the window.

 

Best and fair winds

Ruedi,

WASABI , Amel-54 #55

 

Von: "main@AmelYachtOwners.groups.io" <main@AmelYachtOwners.groups.io> im Auftrag von Sv Garulfo <svgarulfo@...>
Antworten an: "main@AmelYachtOwners.groups.io" <main@AmelYachtOwners.groups.io>
Datum: Sonntag, 27. Juni 2021 um 01:44
An: "main@AmelYachtOwners.groups.io" <main@amelyachtowners.groups.io>
Betreff: [AmelYachtOwners] 24VDC to 12VDC converters: 0V connections

 

Hi all,

 

On GARULFO, and I suspect on other A54s and maybe SM, there are three 24VDC to 12VDC converters, marked “permanent”, “hydra/iscan v90” and “VHF icom”.

 

Of those, only the “permanent” one has the input +0V and the output +0V posts connected. 

 

Does anyone know why that is?

Why shouldn’t the other 2 be the same?

 

In one pic:

 

<image001.jpg>

 

 

Thanks

 

 

Best,

 

 

Thomas

GARULFO 

A54-122

Tahiti 

 

 

 

<IMG_0466[1].jpg>


Sv Garulfo
 

Thanks Arno,

The only equipment officially connected to the permanent converter is the car radio (for station preset memory retention if I understood correctly). Maybe that doesn’t like floating voltage for some reason...

The vhf is definitely transmission equipment so I guess the theory applies there.

The B&G simnet network (for the analog displays) is an N2k implementation, powered in 12V, so again the theory applies I guess. 


Best

Thomas
GARULFO 
A54-122
Tahiti 




On 27 Jun 2021, at 12:16, Arno Luijten <arno.luijten@...> wrote:

My guess is that these are isolated converters. So the input and output are not galvanically connected. This is typically required for radio transmitter equipment to prevent ground loops. This is where you can get all kinds of funny effects because of impedances of equipement relative to the minus/ground lead. Another example is NEMA-2000 supply that (officially) requires a isolated ground as well, so for this you need to use an isolated converter.

It may be they found a problem with some devices not having a ground connected to the battery ground and therefore had to connect the two 0V lines together.

Regards,

Arno Luijten,
SV Luna,
A54-121


Randall Walker
 

Thomas where is this wooden panel? You mention finding an on/ off switch.

Randall
A54#56
Grenada

On Mon, Jun 28, 2021 at 00:21 Sv Garulfo <svgarulfo@...> wrote:
Thanks Ruedi 

We also have an on/off switch for the permanent, but Amel relocated it behind the wooden panel on the starboard side of the chart table. Not sure why, it’s not easier/more difficult to access there...

Cheers

Thomas 
GARULFO 
A54-122
Tahiti 

On 27 Jun 2021, at 09:58, Rudolf Waldispuehl <Rudolf@...> wrote:

Hi Thomas

 

On WASABI we have the same setup, except that there is a separate “Permanent ON/OFF” Switch under the converter (see picture).

I suppose you have another ON/OFF configuration on the Permanent and therefore they bridged the +0 on input and output.

Probably GARULFO do not have a ON/OFF Switch for the Converter Input and therefore the bridge makes your converter permanent as permanent 😉

The other 2 converter are just switched on when you push the green “INSTRUMENTS” button at the chart table next to the window.

 

Best and fair winds

Ruedi,

WASABI , Amel-54 #55

 

Von: "main@AmelYachtOwners.groups.io" <main@AmelYachtOwners.groups.io> im Auftrag von Sv Garulfo <svgarulfo@...>
Antworten an: "main@AmelYachtOwners.groups.io" <main@AmelYachtOwners.groups.io>
Datum: Sonntag, 27. Juni 2021 um 01:44
An: "main@AmelYachtOwners.groups.io" <main@amelyachtowners.groups.io>
Betreff: [AmelYachtOwners] 24VDC to 12VDC converters: 0V connections

 

Hi all,

 

On GARULFO, and I suspect on other A54s and maybe SM, there are three 24VDC to 12VDC converters, marked “permanent”, “hydra/iscan v90” and “VHF icom”.

 

Of those, only the “permanent” one has the input +0V and the output +0V posts connected. 

 

Does anyone know why that is?

Why shouldn’t the other 2 be the same?

 

In one pic:

 

<image001.jpg>

 

 

Thanks

 

 

Best,

 

 

Thomas

GARULFO 

A54-122

Tahiti 

 

 

 

<IMG_0466[1].jpg>


Randall Walker
 

Thomas,
I found the switch it is like the one behind the DC panel in the galley. Really big switches that take up space I will be swapping these out for much smaller ones and labeling them for the next owner. Way to much time spent identifying wires.

Randall
A54#56
Grenada

On Mon, Jun 28, 2021 at 13:40 Randall Walker via groups.io <sailingalbedo=gmail.com@groups.io> wrote:
Thomas where is this wooden panel? You mention finding an on/ off switch.

Randall
A54#56
Grenada

On Mon, Jun 28, 2021 at 00:21 Sv Garulfo <svgarulfo@...> wrote:
Thanks Ruedi 

We also have an on/off switch for the permanent, but Amel relocated it behind the wooden panel on the starboard side of the chart table. Not sure why, it’s not easier/more difficult to access there...

Cheers

Thomas 
GARULFO 
A54-122
Tahiti 

On 27 Jun 2021, at 09:58, Rudolf Waldispuehl <Rudolf@...> wrote:

Hi Thomas

 

On WASABI we have the same setup, except that there is a separate “Permanent ON/OFF” Switch under the converter (see picture).

I suppose you have another ON/OFF configuration on the Permanent and therefore they bridged the +0 on input and output.

Probably GARULFO do not have a ON/OFF Switch for the Converter Input and therefore the bridge makes your converter permanent as permanent 😉

The other 2 converter are just switched on when you push the green “INSTRUMENTS” button at the chart table next to the window.

 

Best and fair winds

Ruedi,

WASABI , Amel-54 #55

 

Von: "main@AmelYachtOwners.groups.io" <main@AmelYachtOwners.groups.io> im Auftrag von Sv Garulfo <svgarulfo@...>
Antworten an: "main@AmelYachtOwners.groups.io" <main@AmelYachtOwners.groups.io>
Datum: Sonntag, 27. Juni 2021 um 01:44
An: "main@AmelYachtOwners.groups.io" <main@amelyachtowners.groups.io>
Betreff: [AmelYachtOwners] 24VDC to 12VDC converters: 0V connections

 

Hi all,

 

On GARULFO, and I suspect on other A54s and maybe SM, there are three 24VDC to 12VDC converters, marked “permanent”, “hydra/iscan v90” and “VHF icom”.

 

Of those, only the “permanent” one has the input +0V and the output +0V posts connected. 

 

Does anyone know why that is?

Why shouldn’t the other 2 be the same?

 

In one pic:

 

<image001.jpg>

 

 

Thanks

 

 

Best,

 

 

Thomas

GARULFO 

A54-122

Tahiti 

 

 

 

<IMG_0466[1].jpg>