Subject: [harryproa] Re: Wiring and water runs?
From: "jjtctaylor" <>
Date: 5/26/2008, 3:14 PM


Here is the problem with types of power. 12KW AC genset is fine for two burner ceramic
cooktop, convection oven microwave, AC water heater, Small size AC fridge (up to 10 Cu ft
or so), and Air conditioning all at once plus about 30 amps or so for batter charger.

It can all work as long as genset is on. Need a victron multi inverter to handle loads when
tied up to 50 amp shore power (or less) to augment shore power with battery power and
give time for genset autostart to begin and warm up the genset.

The issue you have is DC motor is running off batteries, when they are less than 50%
capacity then in a short time you will be limited to motor power at whatever amperage can
be spared by AC to DC battery charger, from whatever source. Essentially charter boat will
have to slow down. Not an easy solution to manage battery rechange with power demands
from DC motors. Might be possible to parallel additional chargers but could make a mess
out of the batteries.

The other option is DC genset, Like example from E-motion Hybrids,

or Glacier Bay (pricey)
They have smaller gensets down to 6Kw.

In any event the DC genset will have controls to charge the batteries when needed, at their
appropriate recharge rate and supply additional power to other users like motors or
inverters directly off the DC bus. The genset will have a control box to set priority to
users. Inverters can be paralled to provide whatever AC is desired, up to their surge/
continuous limit. Therefore motors are not power limited, while AC loads are more so.

To get over the AC requirements hurdle with a DC genset perhaps telecom inverters,
which are high reliability, hot swappable and can be paralleled to some phenomenal levels
like 36KVA or higher. TDI Power is an example. See their LCE series. And they are fairly
lightweight with pure sine wave. Microwave wants pure sine wave.

Lastly voltage and current thruput is an issue as noted on other posts. Higher matching
voltage , happier components (less current, less losses & heat), less voltage stepping up or
down, and smaller lighter wires. Whatever you choose just be sure to check how much
your battery can take in or give out. They can be limiters in themselves.

My system config is 10KW 144V DC genset, 6KW AC inverters, 8KW battery power using
Nilar NiMh batteries in 144VDC bank. Big power users are 8KW 144VDC power pod, 1.8
KW in Air Conditioning, 2KW Micro-convection oven, 2KW ceramic burners, and 1KW
electric heater. Should be able to juggle users to work with 50 Amp shore power.

DC gensets can also be set to throttle up/down depending on loads thus saving fuel. AC
genset must run at a specified RPM and don't like running without a decent load attached.
The AC generator get some phenomenon called wetstacking if motor runs continuously
without a load.

Whatever is done it must be seamless to the charter users, easy to understand, high
reliability, least operator intervention possible (intuitive) and safe.



--- In, "Rob Denney" <harryproa@...> wrote:
> G'day,
> Initial gen set is Fischer panda 12 kw. weighs 186 kgs (plus fuel
> tank), dimensions are h 580 l 700 w 470 It could go under the helm,
> but it limits the possibilities with the steering cables. Easy enough
> to get around. We were thinking of putting it under the bridgedeck
> table (when I get time toi draw it!).
> Instruments on a turntable is a good idea, but we will probably have
> them up against the salon wall so they can be turned and seen from
> inside. The tray on top (with clips) is an excellent idea. Holding
> onto, and trying to read a flapping chart is no fun at all.
> The wiring will run in either conduits glassed under the bridgedeck,
> or along the inside of the beams.
> JT, We are still waiting to hear if a complete 110V system is
> practical. Owner wants to use househiold appliances as they are
> chepaer and easier to fix in out of the way places. Be interesting to
> see how this works out. I have forwarded him the 3 wire system, which
> looks like the way to go.
> regards,
> Rob
> On Sat, May 24, 2008 at 11:49 PM, Gardner Pomper <gardner@...> wrote:
> > Hi,
> >
> > If the generator is to be up on deck, maybe it would be good to put it in
> > the steering pedestal. If you make that wider than usual, then you could put
> > all the nav instruments on a turntable type arrangement on top of the
> > pedastal and just rotate them to face whichever direction the helmsman
> > needs. I am assuming that the steering is by cable, straight down, then
> > through the deck and over to the rudders.
> >
> > On our cruising boat, we found it very useful to have a tray on the steering
> > pedestal, large enough to accomodate a paper chart, so it would be right in
> > front of the helmsman, in addition to any GPS plotter.
> >
> > All this is off the top of my head. Do you have preliminary dimensions on
> > the genset to see if this is even a practical idea?
> >
> > Thanks,
> >
> > - Gardner
> >
> > On Sat, May 24, 2008 at 10:41 AM, Rob Denney <harryproa@...> wrote:
> >>
> >> G'day,
> >>
> >> Wiring runs through and under the walls in the cabin, and in conduit
> >> elswhere. Details are yet to be sorted as the location of the
> >> equipment is not yet finalised. I intensely dislike anything that
> >> cannot be got at and fixed if required, so everything will be
> >> accessible.
> >>
> >> It is not premature to talk about anything. Minimising cable runs is
> >> important and having the power loss between the gen set and the
> >> batteries is (I think, happy to be told otherwise) a better solution
> >> than between the batteries and the motors. It looks like the motors
> >> on the first charter boat will be under the bridge deck, on each hull
> >> with the genset in the middle of the boat and batteries close to the
> >> motors (one set in the ww hull, plus the house batteries, one set in
> >> the lee hull is the current plan. Long cable runs and weight to
> >> windward are definitely a compromise with the motors on the rudders.
> >>
> >> Regards,
> >>
> >> Rob
> >>
> >> On Sat, May 24, 2008 at 8:58 PM, gardnerpomper <gardner@...>
> >> wrote:
> >> > Hi,
> >> >
> >> > I was wondering how the wiring will be run on the charter proa. I have
> >> > gotten the impression that the deck floor will be a single foam cored
> >> > panel. Will there just be conduits attached to the "top" of the floor,
> >> > or along the walls, or will it be embedded in the floor itself? There
> >> > is always a tradeoff between keeping it all out of sight, and still
> >> > having access to it for repairs.
> >> >
> >> > On a related topic, I was also thinking about the wire runs for the
> >> > genset to the batteries and electric motors. I assume the batteries
> >> > will be in teh windward hull, for the ballast, so there will be long
> >> > runs to the electric motors in the lw hull. If the genset is on deck
> >> > for easy access, then it would seem that you have very long cable runs
> >> > for very high amperage circuits. It depends on the specs, but aren't
> >> > we talking about 100' or more of 00 or bigger cable?
> >> >
> >> > I don't know if it is premature to talk about this, but I am curious.
> >> >
> >> > - Gardner
> >> >
> >> >
> >
> >

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