Hi Ken, I appreciate the prompt reply.
AS you may have noticed from my posts on the Trawler list; I am quite involved in electrical design so I am always intrigued by unusual designs.
> -----Original Message-----
> From: Ken Williams >
> Arild:
>
> As you've noticed, the electrical system on my boat is unusual. Most
> of the system is fairly standard for a Nordhavn, but there are some unique
> aspects to the boat, particularly the inverters.
REPLY
That is what caught my eye. I have used similar approaches but not at that level of power application.
Is Mikey Smith doing the design, or someone else?
> Let's start by talking about the cruising alternators. These are
> hydraulically powered by a PTO from the main engines. It's the same
> ABT hydraulic system that powers the stabilizers and the thrusters.
> Each of the two cruising alternators puts out 250 amps of 24 volt power.
>This gives the equivalent of a 14kw 220v generator, without powering a generator on. For
> long passages, this comes in handy.
Steve Dashew uses Electrodyne, I know of one Leece-Neville model also capable of such an output.
In fact I have one sitting on my shop bench. What brand /model are you using?
> There are four 3.5kw Outback (not Victron) inverters that will be
> installed. This will provide 14kw of 220v power. This allows me to
> meet most ordinary
> loads on the boat without firing a generator.
REPLY
I was mis-informed they were Victron but Outback are just as good, perhaps better.
I have only installed one Outback system but was impressed by their quality.
How big a bank of batteries are you installing to support such a large inverter capacity?
I would think that it has to be at least 2400 Amp -Hours or the batteries will not last any reasonable lenght of time.
> The honest reason we did this was to avoid having to start up a
> generator while at anchor. If I have a boat of sleeping guests, and
> want to fire up the expresso machine, this allows me plenty of power
> in short bursts without turning on the generator. If also allows the
> full output of the cruising alternators to be tapped while underway.
REPLY
I did a similar thing on a Michael Kasten design I did last year.
Sure reduces fuel burn if you don't have to run a genset while under way.
> Theoretically, the inverter output is sufficient to run a portion of
> the air conditioning. My hope is that I have sufficient battery capacity to cool
> JUST the master stateroom, while at anchor overnight. On paper we have
> enough amp hours in the house battery bank, so - maybe.
REPLY
How do you split the load between the genset and the inverters when you have central air using chillers.
I noted in your write up that you have four chillers to lessen the start surge. Good plan!
> I have thought many times about simplifying the electrical system.
> Sans Souci will be traveling around the world, and it will be up to me
> to fix things when they break. I'm a software engineer, not an
> electrician. I've been reading books on marine electrical systems, but
> most of this is still over my head. The right answer was probably to
> dump the cruising alternators, all but one inverter and perhaps even
> one of the generators -- just to reduce complexity, and free up space
> in the engine room
> -- but, I've convinced myself I can handle it, and hopefully I'm right!
REPLY
Well if you get stuck feel free to send me an email. Many other trawler list members do, even when they are cruising on vacation.
| Williams, Ken |
2006-11-19 09:36:39
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