Re: [Amel Yacht Owners] Alternators and house batteries

Barry Connor

Hi Thomas,
How is your copper coat project going? I am back on the boat next week and starting to plan my bottom painting.
For my starter battery I know that I have a 12 volt alternator on my main engine, I think that the generator also has a 12 volt alternator. I also have a 12 volt solar panel charging my starter battery separate from my 24 volt panels. My main engine has a separate 24 volt charger for the house batteries.
I carry a 230 volt / 12 volt charger and a 230volt / 24 volt charger.
Plan 'A' If my starter battery died I would disconnect 2 of the 12 volt house batteries and use one to start my main engine or the generator.
Best Regards 

Barry and Penny
"Lady Penelope II"
AMEL 54  #17

On May 23, 2017, at 3:15 PM, John Clark john.biohead@... [amelyachtowners] <amelyachtowners@...> wrote:


Hi Thomas,
   I think that is possible because, on my SM37,  the main engine has two alternators,  one is 24v(for house batteries) and the other is 12v(for starter batteries).   On the generator there is also a 12v alternator for the same starter batteries.

I also have a 24v on the shaft but I think that is outside the topic.

The previous owners staged jumper cables to connect the 24v house bank to the 12v starter bank in emergency to start one of the motors.  They claim this is safe for short time to start motor....

Olivier might know more

Regards John

John Clark
SM 37 Vent de Soleil
Charlotte Amalie, St. THOMAS

On May 23, 2017 10:09 AM, "SV Garulfo svgarulfo@... [amelyachtowners]" <amelyachtowners@...> wrote:

Hi all,

I was reading a Sept 2015 discussion between Bill Rouse and Colin Streeter to learn about the topic of having a 24/12DC converter (not cheap!) or a 12V/230AC charger in case the starter battery requires charging without either engines running.

So the alternators are the sole charging devices for the starter battery. But they are used to charge the house battery bank too, right? How is that achieved then, given the difference in voltage? 

Thanks in advance for shedding some light

Amel 54 #122
Cap d'Agde, France

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