Wiring plans

[BrianR]

I have this old 15 foot runabout from 1957. Its running now, but I want to add some wiring, and another battery, etc.

More specifically, I want to install another battery for a trolling motor, (and to serve as a backup for my main battery) and wires to serve running lights, a radio, a fishfinder,gps and horn.

Here's what I THINK I know so far: I think I want to install one of those battery switches on the transom so I can use battery 1, battery 2, or both. Then, I think I have to run one or two hot wires (and a ground from the battery ground terminal) to a bus fixed under my back seat. I don't know what kind of Bus, what gauge wire I should use, etc. From there, I want to run three or four hot and common wires along the side of the boat, to the dash in front, where I can connect them to a switch panel which contains three switches, plus a push botton horn switch, and a voltmeter which will test both batteries. What gauge wire, I dont know. the three switches will be used to wire the radio, the fishfinder/gps, and the running lights.

Am I even close? Any thoughts or diagrams would be much appreciated.

Thanks in advance all.....

[Bob Smalser]

Isolating one battery with a 2-pole switch is a good idea so electric trolling doesn't drain your starter battery or kill your running lights for the trip home. Otherwise you may be able to do without.

http://woodenboat-ubb.com/ubb/ultimatebb.ph p?ubb=get_topic;f=1;t=009784



First thing you need is a basic automotive or marine electrics book to compute your loads and determine wire size, and make your plan:




Then the instructions with your battery switch should explain how it's wired, as will the combination breaker/switch panel you select, based on the number of circuits and appliances.



I like to go a step higher on the wire gages and build in easy places to splice in additional wire for new appliances in the future.

[ 02-17-2006, 09:44 AM: Message edited by: Bob Smalser ]

[Les Schuldt]

A few thoughts...

Good reference books:
-The 12 Volt Doctor's Practical Handbook
Edgar J. Beyn
Spa Creek Instruments
Fairly Cheap, sketches, tables for wire size

-Boatowner's Mechanical and Electrical Manual
Nigel Caldebr /> Not Cheap, very detailed, everything stem to stern

Cheaper yet, Google search for "Wire Guage Table" and look for some simple explanations.

Some tips:
-Long wire runs kill voltage and require much larger guage wire. Better to have the batteries near the load(motors), switched through a relay(Secondary circuit). Then smaller guage wire can be run to your switch panel forward(Primary circuit).
-When measuring wire runs, remember to double the length. The current has to go to the load and back again.
-Make sure you fuse the + side of each battery.
-Proper crimped connections will make the job last.

[kc8pql]

Originally posted by Les Schuldt:
Some tips:
-Long wire runs kill voltage and require much larger guage wire. Better to have the batteries near the load(motors), switched through a relay(Secondary circuit). Then smaller guage wire can be run to your switch panel forward(Primary circuit).
-When measuring wire runs, remember to double the length. The current has to go to the load and back again.
-Make sure you fuse the + side of each battery.
-Proper crimped connections will make the job last.

I'll add:
-use stranded, tined marine grade wire and crimp connectors. Untined automotive wire and crimps are a false economy. It turns to green grunge and causes no end of problems after a few years.
-do get yourself a book. It will pay for it's self in trouble avoided.

[paladin]

gimme the max current used by the motor, which I assume is 12.6 volts nominal...and I'll draw a purty piktoor with all the associated wire hairs fer ya...need a snail mail address....

[RodB]

There are several books on this subject ... the following are two of the best:

Boating Mazazine's "Powerboater's Guide to Electrical Systems" by Ed Sherman

"Boatowner's Illustrated Handbook of Wiring" by Charlie Wing.

The "Weather deck" switches by Blue Sea and also their rocker... water proof panels as shown in white...above... are nice (they come with built in fuses or breakers) but the absolute best switches are the individual ones that only have two prongs coming out the back end of a small black box. Many of the other so called waterproof switch panels have resistor boards that will be exposed to the enviornment to some degree...but the simple black rocker type that can be installed individually (about $12.00 ea) offers the most protection and can be installed in "threes" with plastic plates.

There is a great Blue Seal combination "bus and fuse panel" that comes with a plastic cover and although expensive ($50 or so) it is one of the cleanest instalations that can be had... check out bluesea.com

The Blue Sea battery swtich (which is offered by West with their name on it) ... is one of the best...and the best deal is at the "Academy" stores under the Blue Sea name...and only cost about $23...where at West or Boaters World they cost over $32.00. Be sure to not only use marine connectors with proper crimps but also be sure to shrink wrap all connections (Anchor adhesive lined shrink wrap) for maximum longevity. Hamilton Marine has some of the best prices on quality marine electrical supplies.

I would recommend using 4 gauge wire from the battery to the battery switch, and 8 gauge from the Batty switch to the bus bar. All the rest of the wiring depends on the distance and amp draw of the applicance.

Good luck,

RB

[ 02-17-2006, 03:13 PM: Message edited by: RodB ]