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21feetofnewb 01-21-2009 09:09 PM

Electrical halp?'s the deal. I just got a boat and I'm left with the task of wiring it. Its a decent boat that I can't find ANY INFORMATION on...I wouldn't mind replacing all the stock wiring (all new stuff obviously) but I can't find anything about it. I guess what I'm asking is for a little help understanding wiring. I plan on going out...a lot but I am mooring for the time being and won't have a lot of time to charge until I get back home. So I want to know the best way to keep creature comforts (I.E some form of refrigeration, lighting, and maybe my laptop) but not eat up my did most of you reduce the power consumption of your boat while not living like a cave man. I don't have ANY of the wiring in the boat as the previous owner just yanked EVERYTHING out of the boat. I guess the question is really obscure as I don't know so much what Im asking...I want to run enough lighting to keep the boat comfortable, I want a fridge and I want the battery to be able to last me 4-5 days straight...thats what I want help with. So if anyone has a diagram for the boat or something of similar size then fantastic and also a list of things they have used to reduce their power with out reducing their fun... Thanks a lot!

Brett Harding

bubb2 01-21-2009 09:34 PM

badsanta 01-21-2009 09:40 PM

There is a lot on this site, just search it out. My advice is to read ALOT. 12 Bible is good. Jon Payne is also. There are a lot out there. Try But read first, then ask questions. You will get some great advice. But you need to know what you want first. Like I said search this site, lots of info already here.

Perithead 01-21-2009 09:41 PM


One thing I think you should reconsider is having a refrigerator on board. I doubt there are many sailboats your size with refers on them. In fact, Most 30's probably don't have refrigerators either. I know my 29' doesn't.

The fridge draws A LOT of power. So, you need something like a HUGE battery bank, an inboard with an alternator (I doubt the Kells has one), an outboard with an alternator (but you will have to run the outboard alot depending on the size of your battery bank), or a generator. All of these things are pretty tough to get on your average 21'er especially a trailerable one.

You may be thinking solar could be the answer but it would take a whole bunch of panels to power a fridge.

First, you need to decide just what you really need on the boat. What you should focus on first is navigation lights, and a VHF radio. Then consider other things like a radio, interior and courtesy lighting, and maybe your laptop.

I think you should focus on everything except the refrigerator first. I do not know how much money you are wanting to spend, but I bet it would take alot of $batteries$ to power a fridge just on one charge for 4 days.

Once you figure out what you need, then you just need to learn the basics of wiring. Basically, everything needs power and a ground. All you have to do is run two wires (power and ground) to the electrical devices from your battery bank.

Once you decide what all you need, we will walk you through the wiring part or point you somewhere that would give you the answer.

sailingdog 01-21-2009 09:54 PM


If you want a refrigerator to last 4-5 days on a 21' boat, you're hallucinating... it really isn't going to be realistic, since you'd need a huge battery bank to do so.

What you really need to do is get a good idea of what you're going to be using in terms of electricity. LED lighting will help reduce the numbers, but refrigeration is one of the biggest users of electricity on a boat, unless it is engine-powered, which is pretty unlikely on a 21' boat.

As for planning the system out, you should refer to one of the good books on boat electrical systems, like Nigel Calder's Boatowner's Electrical and Mechanical Manual.

Also, being on a mooring, you'll probably want at least a small solar panel, which can help prolong the time you can go between recharging the batteries.

21feetofnewb 01-22-2009 08:12 PM

well as far as wiring I was looking at spending no more than 1500. i have doen some reaserch and your input was a big lew of a fridge I will be a using a colman cooler ^_^. I will be looking at solar panel power but a bit pricy for the boat needing other things first. I might just get an outboard with an alternator to help build a little power when I need it...I would assume it would be like having a small generator...but with the ability to propel myself if need be. It'll make trailering a bit easier i would assume...I bought the 12 volt bible just waiting for it to get shipped so in the mean time...I wait. I will be going with LED lighting. Its a small space so I'll only be using two lights. but either way thanks for the great responses, I found the electrical section in maintenance...TON of info. This is the begining of a beautiful relationship!


tager 01-22-2009 08:28 PM

Ignore these naysayers!
If you want a fridge, get a fridge, but here are my suggestions;

Get a propane (or other fuel) fridge, electric ones will KILL your batteries fast.

Or just jam your needs-to-be refrigerated stuff in an icebox in the lowest part of the bilge. You will have ice for a week around here. (PNW winter)

xort 01-22-2009 10:25 PM

You will need to look at the whole system.
How much room do you have for deep cycle batteries? That will limit what you can do.
How much charging capacity do you have for those batteries? Shorepower? Generator? 110 volt charger? Engine alternator? Solar panels? Wind generator?
With that you will have some idea of how much power you have to use. Then you can decide what to do with it.

How much does a block of ice cost that can last a weekend vs a big bucks installation?

You might consider a small portable refer that can plug into A/C or D/C. You can cool it down at home where you pack it, keep it cool plugged into the car on the way to the boat. Then add a block of ice to keep it cold on the boat. You might also be able to plug it in while motoring to give it a boost.
Take a look here: Cooler - Water Coolers - Refrigerators - Freezers - Beer Dispensers - Wine Coolers

erps 01-22-2009 10:44 PM

Our second boat was a 25 footer with a Honda outboard. The electrical consisted of two small batteries, the nav lights a radio and a couple of interior lights. We used a candle lantern for an anchor light. We used an ice box that needed ice about every third day. It never occurred to us to worry about power, because in the summer, we really didn't use any. It wasn't until the boats got bigger and we got refrigeration that I paid attention to power consumption. Now we've become enslaved. But the beer is cold!

peikenberry 01-22-2009 11:11 PM

A list of good books

Boatowner's Mechanical and Electrical Manual, by Nigel Calder
The 12 Volt Bible, by Miner K Brotherton and Ed Sherman<O:p</O:p
Boating Magazine's Powerboater's Guide to Electrical Systems by Ed Sherman
Sailboat Electrical Systems, Don Casey, 1999 International Marine
Boatowner's Illustrated Handbook of Wiring, by Charlie Wing
Your Boat's Electrical System, by Conrad Miller and E. S. Maloney
Managing 12 Volts, Harold Barre 1997 Summer Breeze Publishing

Basic Electricity New Boatbuilders Home Page - Basic Electricity DC Page 1

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