Electrical systems on a cruiser

Wiring your boat, How to Wire Lights/Accessories, All things electrical other than actually powering your boat by electric motors.

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Scot2640
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Electrical systems on a cruiser

Postby Scot2640 » Thu Aug 04, 2016 8:19 pm

Going along with my previous post on hot water: my subject line is a whopper of a question, I know.

For extended periods at sea how does a boat generate electricity for small appliances and other electronics? On a craft under 30' are you required to keep the engine running at all times or does some kind of battery bank or generator system come into play?

I've worked with a/c in residential applications and am fairly comfortable doing rough and finish electrical work. I am by no means an expert or licensed electrician so the science behind electrical systems escapes me.

Understandably my question is a broad one, perhaps you folks could recommend a book or two I should look to pick up.
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raymacke
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Re: Electrical systems on a cruiser

Postby raymacke » Thu Aug 04, 2016 10:18 pm

There are usually three main components involved - 1. House battery bank 2. Generator and 3. the Engine.

On my True Grit we have two 6 volt golf cart batteries connected in series to create a 12v "house" bank. This is used for our normal 12v loads like lighting, fans, bilge pumps, laptop, am/fm radio, TV etc. This bank is in addition to and isolated from the 12v starting battery. I also have space allocated to add two more 6V batteries for a second bank when we start doing longer cruises IF I feel it is needed. But for our current long weekend outings (usually 4 nights) the one bank has been working OK.

Next is a generator. It is used for charging the house bank and heavier 120v loads like the electric water heater, coffee maker and microwave. We do have an inverter installed that will draw from the house bank and create 120v but we only use this for light loads - actually we rarely use it. In our situation the only 120v items we usually need to operate are ones that call for higher amps. Some of these could possibly be run from the inverter but you will find they can quickly deplete batteries. So then you need more and bigger batteries. And then you need a way to charge these which usually means a bigger generator AND the willingness to let it run for hours on end charging the batteries. So we usually skip the middleman (inverter) and just run the generator. Our biggest user is the 6 gal water heater and it takes about 35 to 45 minutes with our Honda EU2000 to bring water up from room temp to hot. But once heated it usually stays warm enough for showers for two days in the summer (only one day in cooler weather).

The last component is the engine. Our Honda BFP60 (60hp) has excess charging capacity of 22 amps*. Properly wired it can be used to recharge the house bank when underway. Usually on our long weekend trips we travel several hours each day and that does a good job of replenishing the house bank. Occasionally, if not cruising much we will start to see the voltage dropping and then we run the generator to power the on-board 40 amp house bank charger. The load on the generator for this is fairly low so it is not working very hard and is not too annoying. If using an I/O or I/B they can be equipped with larger alternators to help pickup the charging needs or could replace the generator if you don't mind running the engine for hours while sitting still.

One thing I didn't mention is refrigeration. This can be a huge power suck and if running it off 12v you will need at least double our house bank and still plan to run a generator on a daily basis. We opted for a non-conventional (for marine use anyway) solution of having a RV propane refrigerator. Going this way is not a decision to take lightly as there some serious concerns. But for us it has work out very well. It could be a whole topic itself.

For reference I have "Boatbuilders Illustrated Handbook of Wiring" by Charlie Wing that has been very helpful. I also have "Your Boat's Electrical System" by Conrad Miller and E S Maloney. I don't find it as useful but still helpful at times. Both can be bought used on Amazon for $10 to $15 so not too bad. BUT NOW I see Glen-L has wiring diagrams available for some designs and I would encourage you to take a look at that too.


*NOTE - This is not the total alternator output but the amount of excess amperage available beyond what is needed to operate the engine. Also, any load attached to the engine side of the electrical system - like a GPS or radar - will reduce the available amount for charging.
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Scot2640
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Re: Electrical systems on a cruiser

Postby Scot2640 » Fri Aug 05, 2016 12:21 pm

Thanks a lot ray that was very informative. I think I watched a video interview with you discussing the propane fridge. Never even heard of such a thing.

So much to learn! I appreciate the help!
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partager
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Re: Electrical systems on a cruiser

Postby partager » Sun Aug 21, 2016 9:55 am

Hello

Most interesting postings. Ray did you considerer solar power as an alternative for charging your house batteries? I am new to the Forum and my goal is to build a modified Argosy Trawler in the next 3 years. I live in Margarita Island (Venezuela) which has a long tradition of building artisanal fishing boats of 40 to 70 feet called Pargo Mero (Snaper-Sea Bass) that you can find all over the eastern caribbean...thats my inspiration

My english is a bit rusty, so please bear with me
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Re: Electrical systems on a cruiser

Postby raymacke » Mon Aug 22, 2016 6:51 am

I did consider solar but physically couldn't get it to work. Just didn't have the space to mount the panels. The front of my cabin roof has the radar and antennas mounted. Behind that is a roof vent and an area I plan to someday add an A/C unit. The aft 1/2 of the top is where we carry our 8' inflatable dingy. I need either less "stuff" or a bigger boat. :P
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partager
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Re: Electrical systems on a cruiser

Postby partager » Mon Aug 22, 2016 8:21 am

Yes ! I started with the idea of a 28 feet mini Trawler and now looking at a 40+ :D . The Argosy design looks a bit old but really rugged and seaworthy. Ideally suited for island hoping in the Windwrad Islands of the Easter Caribbean...I have done some thinking as to how to incorporate solar power in an electrical setup for PARTAGER (To share in french). I made a very simple diagram (PDF) but for some reason I can not attach it...
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raymacke
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Re: Electrical systems on a cruiser

Postby raymacke » Mon Aug 22, 2016 9:21 am

I don't think the system is setup to handle PDFs. I just tried to do it and it won't work for me either.
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partager
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Re: Electrical systems on a cruiser

Postby partager » Mon Aug 22, 2016 11:14 am

Thanks ! Will figure out how to make atachments pictures
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Bill Edmundson
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Re: Electrical systems on a cruiser

Postby Bill Edmundson » Mon Aug 22, 2016 1:35 pm

See if you can save it as .pdf.

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raymacke
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Re: Electrical systems on a cruiser

Postby raymacke » Mon Aug 22, 2016 3:17 pm

Bill, just tried again and it doesn't seem that PDFs are working. When trying to attach it says it is an "Invalid file extension".
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Bill Edmundson
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Re: Electrical systems on a cruiser

Postby Bill Edmundson » Mon Aug 22, 2016 3:43 pm

Sorry, I meant .jpg.

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partager
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Re: Electrical systems on a cruiser

Postby partager » Mon Aug 22, 2016 4:08 pm

ELECTRICAL 2.0-page-001.jpg
Not easy but finally manage it. This is a very simple linear diagram of an electrical system for a 4o+ Trawler. AC DC POSITIVE. DC NEGATIVE
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Re: Electrical systems on a cruiser

Postby partager » Mon Aug 22, 2016 4:16 pm

ELECTRICAL LOAD CALCULATIONS 2.0-page-001.jpg
And here is where all the juice goes to
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Re: Electrical systems on a cruiser

Postby Scot2640 » Mon Aug 22, 2016 6:52 pm

That's great stuff, thanks!
A ship is safe in the harbor, but that's not what ships are for.

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Re: Electrical systems on a cruiser

Postby partager » Wed Aug 24, 2016 9:41 am

Guys:

FYI there is a link that allows converting PDF to JPG

www.pdf2jpg.net

My 2 cents: Use it for one PDF then close it, open it again and do the next PDF, and so on
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