Revamping Electrical

[TritonSailor]

I need to revamp the electrical on my old but cool boat. I have an idea on how to do it. I just don't know where to begin and what I need. I bought a Blue Sea 8 breaker DC panel and an ACR. I also have a 245ah 8d 12 volt house battery. I've yet to buy wire, not sure what size 12 or 14 AWG? Don't know what kind of busbars and such I need. I know that's what I want though because I want organization. I will be tying in a VHF, SSB, Nav Lights, blower, bilge, Interior lights, and a Raymarine E80 series Superpack. Suggestions will truly be appreciated. Oh, forgot, I also got a battery switch.

Thanks,

Jeff

[barnakiel]

Grab Calder's book and read it. All your answers are there. Only 50 bucks and will re-pay many times over along the re-fitting way.

b.

[Sandero]

Jeff,

The wire size is determined by the length of the cable (pos and neg together) and the load in amps they would carry. I can email you a spread sheet which computes the correct wire size.

Use tinned stranded copper. Double crimp connections and use heat shrink over the cable and the connect. You can label every cable with using clear heat shrink and labels you print on plain paper. The label should indicate what it's connected to at the other end. It does get complicated and lots of wires and cables which all are either red or black!

You'll want a small start batt of the same TYPE as your house bank.

I would recommend a Blue Seas 8080 switch or something similar which allows you to combine the house and start banks and switch each one on and off independently and provides a 100amp circuit breaker for house loads.

You can go to Blue Seas to locate all the proper components like buss bars fuse holders and fuses. The large loads like windlass or inverter should be connected BEFORE the main batt switch to a 600 amp buss bar with with ANL or Class T fuses.

You'll need some appropriately size buss bars at some locations because you will have a lot of pos and neg wires needing to be connect to the batt pos and neg posts and it gets kinda crowded on one post.

Remember to fuse all wires to protect them from overheating from shorting and starting a fire. Fuse are sized to the load of the wire.

You should probably use an Echo charge to charge the start bank and use a 4 stage smart external regulator and a high output alternator such as the MaxCharge 612 regulator.

Then you might want a monitor system such as the Xantrex Link which tracks the state of your electrical system by reporting the voltage and the amps in and out among other data.

And that's the basic 12v system as I see it.

Several companies make this gear so this is not an endorsement of the gear noted as much as a reference for you to see the function.

[TritonSailor]

Defjef,

Thank you for responding. I already got a battery switch http://bluesea.com/category/1/products/11001.
As far as the buss bars and fuse holders, that's the question I have, I don't know what size to get when it comes to buss bars and terminal blocks, what amps? Would a high output alternator be too much for my Atomic 4? Where would you fuse the wire? Im sorry for the questions, but this is an area where I won't win by trial and error.

Thank You for your time

Jeff

[Sandero]

I am certainly not an expert, but I think you atomic can handle a high output alternator - Balmar, would know for sure.

The fuse goes between the battery and the load / device.

The wiring is pretty simple.

Wire and fuse size are based on the load.

Why don't you try to do a diagram and post it or email it and we can edit and correct it as necessary?

[Beausoleil]

Before you worry about specific equipment, do yourself a favor: after you purchase and read Calder's book, create a list of all the electrical devices you want to power and then draw up a simple schematic diagram and post it here. If you want to do this project yourself, the forum can help - to a point...

Even though I'm a degreed electrical engineer, I still sought input from people here when I designed Beausoleil's electrical system...

[Roy M]

Triton, Follow Beausoliel's advice. Do a couple more things as well: Create an Excel file at the outset of this adventure. On sheet one do the following: Label across the top the following: Circuit name and number, electrical device powered by this circuit, amount of time in 24 hours that the unit is probably going to be used, the current draw of the unit, the product of the current draw and the 24 use cycle. This provides you with an idea of how much juice you expect to use in a day's time, an idea of how much juice you are funneling through each circuit breaker, and an idea of how big a battery bank you will need.

Start sheet two and label the top: Circuit name and number, distance to the unit and back to the panel, wire size. Under the circuit name list the device and fill in the empty column info, using a wire sizing software such as Blue Sea Systems# or the West Marine catalog. At this point you might consider a distributed system where a circuit powers busses that then feed power out to the various lamps, etc, as opposed to individual wires from the panel to each device in the boat.

Now, consider the toys that you might want ten years from now. Do you have spare circuits available, conduits or existing wiring to carry the power to those future loads? You will have to plan for it sooner or later. It's easier to do it sooner and set up the supply wiring, even if you don't install the breakers and busses now. You'll even get a head start on making sure you have the battery capacity for the future.

Now you can go completely crazy and give each device and length of wire a label to identify it when you string it in the boat and have to identify it later on (it WILL happen). I label my stuff with the circuit number first, followed by the feeder wire lable, then the wire going from the distribution buss to the device. For example: 01-01-01 means PORTSIDE CABIN LIGHTS CIRCUIT BREAKER (01) connected to the FORWARD CABIN LIGHTING CIRCUIT BUSS (01-01),connected to the FORWARD CABIN BUNK LIGHT, INBOARD(01-01-01). I made up the spreadsheets, followed the wire size requirements for 3% line loss, bought the lengths of wire needed according to the sheets, pulled the wires and labeled them at each end, then connected them to the origin and destination for each label. Then I colored in the completed lines to show my progress and where to begin where I left off.

With 16 DC circuits and several AC circuits, it really helped to keep me (somewhat) sane and solvent. My panel is in the center of the boat, with five major conduits leading to various parts of the boat. You want to pull all of the wires in any one harness at the same time, meaning they need to be precut, prelabeled and tightly bundled. Doing so also adds some calculations to the current draw, as does passing them through engine spaces (better to use conduits). When this boa constrictor arrives at a distribution center, it really pays to have stuff labeled.

[GordMay]

All good advice.

After calculating your approximate electrical demand, as others have explained, I generally install as much battery capacity as I can (space & weight).
You cannot have too much power on a cruising/live-aboard boat.

Wire Sizing Charts and explanations:

“Ohm’s Law & Boats”
➥ http://www.cruisersforum.com/forums/...ats-372-2.html

Wire Size Chart (1)
➥ http://www.cruisersforum.com/gallery...r&imageuser=79

Wire Size Chart (2)
➥ http://www.cruisersforum.com/gallery...r&imageuser=79

Basic DC Wiring Diagram
➥ http://www.cruisersforum.com/gallery...r&imageuser=79

More Info':

Electrical Study Hall
➥ http://www.cruisersforum.com/forums/...all-10632.html

Evaluating 12V Flooded-Cell Batteries
➥ http://www.cruisersforum.com/forums/...ies-12707.html