Main power off switch for charging and wire guage?

[user 10949]

I'm working on the wiring diagram for our boat. the electronics include:

12v 55# front troller
12v 45# rear troller
fish finder
running lights
anchor light
LED cabin lights white
LED cabin lights red
12v accessory (lighter)
USB charging bus

Each item will have an individual fuse and on/off switch on the panel. i was planning to use solid wire, not a braid.

#1 should there be a main on/off switch between the battery and the bank of fuses/switches for charging purposes? I see the big red knobs and don't know if that's just for 2 bank battery switching or for a main breaker.
#2 how heavy of a wire should the main power cable be? from the battery to the bank of fuses/switches?

 

[BassBlaster]

I asked a similar question awhile back about the main power switch. I too was worried about sending current throough the lines during charging. I was told it wasnt neccissary, just make sure everything is powered off before charging.

Im interested in hearing the replies about useing solid wire as I havnt heard of that. I thought solid wire was reserved for higher voltage and AC current like in a house.

 

[RiverBottomOutdoors]

Pulling/fishing solid wire can kink it and sometimes stretch it if you're not careful. Either one will affect the electrical properties of the wire.

Not sure if you'll be fishing wire....if so, it's just something to be aware of.

 

[tsaints1115]

Why not go with a fine strand marine wire? I just ran 4 gauge in my boat and it very flexible and easy to use.

 

[user 10949]

moisture is inevitable and ruins the wire casing. when it fails the braided wire seems to allow moisture to wick inside the cable where a solid has no channels inside. 10 times I've found myself in some uncomfortable position, fishing for a wire trying to repair some electrical failure and 9 of those 10 it's been failure of the braided wire due to corrosion where I feel a solid wire would not have failed.

i feel like solid is much more reliable and terminates cleaner.

 

[tsaints1115]

The wire in marine cable is tinned for that reason.

 

[krawler]

Everything connects here, batteries to the main switch I used 4 gauge, wires going to both trolling motors I used 6 gauge and wires going to the switch box I used 10 gauge. There are circuit breakers on both trolling motors and a 30 amp fuse on the wire to the switch box. All grounds are connected here also.

 

[RivRunR]

You don't need to put your trolling motors or your fish finder on a switch...they have their own internal on/off switches.

Each trolling motor circuit should have a circuit breaker, as close to the battery as possible. Breaker size depends on amp draw of the motor and length of wire run (both directions).

The size of your "main power cable" to the fuse box also depends on amp draw, but you can't get too big. You can probably use the same gauge as whatever you get for the run to your trolling motors (maybe 6 gauge?) to save a few $'s. You should also install a breaker on that line between the battery and the fuse panel. Again close to the battery, and again breaker size depends on amp draw and length of run.

Here's a chart you can use to figure out what gauge wire you need based on amps and length of run: Blue Sea Systems

As mentioned above, use tinned marine wire, not solid...here's a source: Tinned Marine Wire. They also have duplex (and triplex) wire, which may have the properties of solid wire that you were looking for.

I wouldn't think you'd need a battery switch at all, but maybe I don't understand your set-up. You don't need one for charging.

 

[user 10949]

The wire in marine cable is tinned for that reason.

tinned wire you say? I'll look at that. somebody should call Skeeter, guess they didn't get that memo either :roll:
i could get to work on my own if i wasn't so busy pulling rotted wires on my buddies boat!

Krawler

That's a clean install there and looks just like what I have going on in my mind. i like the little ground bar you have going on under the red switch and wonder if / how it's insulated from the boat?

You don't need to put your trolling motors or your fish finder on a switch...they have their own internal on/off switches.

Thanks for the links! Think I was thinking of shutting off power to equipment while charging and also having a safety shut off right by the battery, in case of some kind of failure i could kill everything on my floating conductor.... but i wasn't really separating the 2 concepts in my mind #-o

Thanks everybody for the input!

 

[krawler]

When the gas outboard is off the boat the hull is not bonded, so I made sure the grounding buss is bonded here.

Now before someone gets their panties in a bunch about using the boat as a ground, just note that the hull is not an electrical ground this is just a bonding point.

Bonding is to ensure that all metal components, batteries, and trolling motor are at the same electrical ground potential to prevent corrosion. When you have a gas outboard with electric start attached to an aluminum hull then the boat, motor and battery will be bonded together.