Adding an inverter

[Zanshin]

My boat has a factory (Jeanneau) installed 3-way rotary switch for AC power - "Shore" to "off" to "Generator". I am thinking of changing that to a 4-way switch and adding a "Inverter" section to power the AC plugs from an inverter (which I haven't purchased yet). I am rather far away from the boat right now and wonder if typically the wiring of boats is such that this could be installed without having to do much (if any) rewiring. I'm envisioning just running power from the house battery bank through this switch and an inverter to the AC net; hoping that the different power sources are truly separated with both (+) and (-) switched.

Is this a realistic job or is it simpler to go and purchase a separate inverter that plugs into the cigarette plug on the instrument panel? I'm only planning on running the notebook or camera charger or an espresso machine off the inverter (with with the coffee machine being at the top end of the list since I've learned that I cannot make a percolated coffee palatable and worry a bit about making filter coffee while underway on an unstable platform).

If my Cristec charger breaks down I will probably replace it with a charger/inverter but that is a cost I'm not interested in paying yet.

[camaraderie]

Given your uses...you don't need to go through a lot of wiring if you already have a battery charger hooked up to shore power. Just wire a decent inverter into your battery bank and run your "at anchor" A/C from the inverter or a power strip attached to the inverter. The coffee machine will draw around 1200 watts (10 amps at 120V) so be sure to get at least a 1500 watt inverter.

[tmhdgpth]

Have you tried a "french press" coffee maker? All you have to do is boil water, and they beat the "coffee machines" by a ton!

[Zanshin]

Camarad,

thanks, the suggestion makes sense; in a way. I think I'm imaging a potential shorting problem if I add an inverter, since right now the A/C plugs can be driven off either shore power or from the generator. My thoughts (or hopes) were that I could supply A/C through the existing plugs via a 3rd source without messing up the configuration for Shore/Genset power. I think I'll have to trace the A/C wiring and see if it all terminates in one place.

[Zanshin]

Originally Posted by tmhdgpth

Have you tried a "french press" coffee maker?

No, never tried them. I have a nifty coffeemaker that grinds, tamps and makes some of the best coffee I've ever made - all I need to do is keep the water level topped up and occasionally remove the grinds. I've kind of set my mind on putting this technological masterpiece into the galley (even went to far as to measure where I need to drill to secure this beast).
I tried several times to percolate with the hardware on board and it always ended up tasting bad. Too many memories of HoJo's at 4am during college... I think that a fine cup of Joe is one of those luxuries I'm not willing to dispense with onboard. Luckily I don't watch TV or I'd probably attempt to get a big projection screen installed.

[btrayfors]

Zanshin,

Camaraderie is right: do yourself a big favor and just buy an inverter large enough to handle the coffee maker, and hook it up directly to your house batteries.

It's clear from your remarks that you haven't yet done the research, and learned that a proper "4-way switch" able to handle shore power and generator power (30amps) as well as inverter power will cost a bundle. Furthermore, unless you have a knowledgeable friend qualified in marine electrical systems it's gonna wind up costing you some bucks....far more than the cost of the new charger you say you don't want to buy.

Small inverters are cheap, simple to install, and will do the trick for you.

The more complex route of tying in a (permanent, substantial) inverter to your boat's AC and DC systems will not only be costly in itself, but will raise problems such as potential for killing your batteries if, e.g., the hot water heater is left on while the inverter is switched on.

IMO,

Bill

[ebs001]

Zanshin,
The simplest way is as suggested by Cam and BTF to hook in a 1500watt minimum inverter and plug your coffee maker directly into the inverter. You will need to size the wires from the battery bank to the inverter appropriately. For 1500 watts you would need minimum 2/0 wire. As the load is mainly just a resistive load the far less expensive modified sine way inverter will fine for your application. Your 3-way switch switches the A/C not the D/C as is suggested by your original post. The fact that you even asked about that says that you should only tackle the simple way which only requires working with 12 volts DC. This is not cheap $400. If you only want to run a laptop an inexpensive plug in inverter works fine. They are around $60 and require no wiring if you already have a cigarette lighter outlet.

[sailingdog]

Zanshin-

While your original approach to the problem is one way to do it...it is probably far more expensive and laborious than the way that Cam has suggested. Unless you have a truly massive battery bank, and can see needing all of the outlets for different things running off of AC power, and are willing to purchase a massive inverter...there is absolutely no point in having all of your existing AC outlets live with the inverter as a source.

It would make far more sense to have just a couple of outlets connected to the inverter and marked as Inverter-powered outlets in some way. That way you have access to AC-power when shore power and the generator are both not options.

[Zanshin]

Thanks for all the comments. I received the wiring diagrams yesterday and started tracing through them last night.
Btrafors - the 4 pole, 4 pos 63A Kraus Naimer switch runs at $60; that is not exhorbitant for this intended purpose, and I never stated that this switch was for DC.
The way it is wired looks like putting that switch in on the AC side would require rewiring (particularly since I would need to isolate the charger to make sure that it cannot get AC power when running through the inverter).
As has been stated several times, the simplest solution will be to use the 12VDC plug in the panel and hook up a portable inverter there to power small devices like laptop chargers and coffee makers.
Thanks!

[camaraderie]

NONONONONONONO...do NOT use a 12V lighter plug to wire it up. You must wire it up using HEAVY guage wire directly to your battery bus. Preferably around 04-06 guage for the load you are trying to drive with the coffee mager...you will be pulling high current perhaps 80-100 DC amps!!