Wiring Advice

[Baxter]

I realize with 12V systems there are a million different ways to do things, more than one right answer. But I want to ask a question, and get some advice on how you guys have your boats wired, specifically when it comes to accessories.


I have posted a pic below, apologies if it is confusing

Current Situation
There is a hard wired 10ga wire going direct from the battery into the sounder, bypassing the switch etc. There is an inline fuse.

In addition, all negative leads from all the stuff tie directly to the one battery. Sure it works, but it is a mess and I don't like it. I want to clean this up with a busbar.

(If it matters, the boat currently had dual 12v batteries. The kicker charges as well as the main. There is a 1/2/1+2/off switch that almost everything goes through with the exception of the Lowrance and the Bilge)

Planned
I want to run the sounder through the switch (no idea why last owner didn't do this, everything else on the boat goes through the switch). To do this though, I need to replace the 10ga wire that is currently run as it is too short to reach the switch. I figure, while I am at it, I will upgrade the gauge of the wire to accommodate future add-ons.

Planned additions include a compass, interior lighting (probably just led strips, but unsure), and a stereo (basic marine grade car-type stereo, nothing fancy, no amp or anthing).

Question 1: is 10 gauge likely enough? Should I go 8? or other?

Plan:
- Add a bus bar at the rear of the boat for all the negative leads (bilge, washdown, motors, etc).
- Add a pair of bus bars at the front of the boat, one for positives, one for negatives for all the stuff up there (sounder, radio, vhf, compass, sounder, etc).
- Replace power cable with higher gauge (if a good idea)

Question: Does this plan (also see pic) make sense? Is this a good idea? better idea out there? (I have thought of adding a fuse panel instead of the positive bus bar - not 100% certain YET on how all that connects, but I know I can figure it out if it is really the best way to go.

That is the gist of it. I have an electrician friend who is happy to help me with this stuff, and I plan to run whatever I come up with past him before going for it, but really wanted to get the opinions and ideas from other boaters who may have a similar situation. Of course I am also about to scour YouTube for ideas also, so telling me to just reference YouTube is pointless


(Edit: In my "current" drawing below, there is an inline fuse for the sounder, so no need to call me out on that, just forgot to draw it )

 

[zurk]

i go 2 guage from the battery to a blue seas dualbus hub whereever i want to put accessories. then i go 12 guage to those accessories with a fuse on the dualbus hub. it works out much cleaner that way and you can use 2 guage to connect dualbus hubs together in a large string.
so none of that big mess of wiring required.
battery --2 guage -- dualbus hub ---12 guage to accessories or 2 guage to another dualbus hub.

DualBus Plus 150A BusBar - 5/16"-18 Stud 5 Gang - Blue Sea Systems

Combines negative and positive buses on one block.

www.bluesea.com

 

[Baxter]

Actually, thinking this may be the answer, battery to this fuse block (https://www.bluesea.com/products/5025/ST_Blade_Fuse_Block_-_6_Circuits_with_Negative_Bus_and_Cover) , then to accessories
As Zurk suggested:

battery > 2 ga > Fuse Block > 12 ga > 'accessory'

 

[Brando]

Use a fuse block for the front, you likely do not need a 2ga feed to the front of your boat that seems outrageous for a small boat.. 4/2 or 6/2 should be sufficient. size the fuse accordingly at the battery side based on your wire choice. I would invest in a blue seas ACR and isolate your main battery for starting that would eliminate your 1/2/off switch and simply be on/off one battery becoming a “house” battery which runs your electronics. The charge relay will then regulate between the 2 automatically worth the investment while your at this!

there are 12v charts online to help you calculate the wire size. Add up all the electronics based on their fuse size and refer to the chart leave some extra room for additions and voltage drop.

 

[Sharphooks]

I agree that 2 guage is overkill. It will also create fishing issues (as in wire fishing through tight quarters) and connection issues (as in ring terminals perhaps being too large for the busbar connectors)

THat BlueSea wire gauge chart that Brando posted with wire gauge/wire length/volt drop etc should be your bible. Calculate all the amps your various accessories will require, then the distance of the run, and you can see the proper gauge you’ll need to be consistent with ABYC standards (or Canadian equivalent) . I usually go up a gauge from what the BlueSeas chart stipulates as a safety factor and that gives me the flex to add another accessory or two at a later date and still be compliant

The BlueSea ACR is also good advice (Automatic Charge Relay) , but you should be cognizant of the downside of that unit so you can be prepared to troubleshoot if you have issues

Case in point: if the ACR, once installed, senses a voltage imbalance between your house and start batteries, you can sometimes run into voltage issues which might effect voltage-sensitive electronics, like chartplotters and fly-by-wire for your outboards.

When I first installed my BLueSeas ACR, I was paranoid about the parasitic voltage draw it uses (very small but can add up over time) So I placed a switch in there that could isolate it from the batteries. Then of course I forgot to turn it back on one day while running the boat and lost my Furuno chartplotter when the house battery voltage got beat up ....I was running duo-Scotty downriggers on the house battery (which weren’t getting replenished by the main outboard alternator because the ACR was in “off” position), resulting in 11 volts, not enough to run the Furuno and it crashed.

I also lost fly-by-wire one day, leaving me dead in the water...my Suzuki ran, but it wouldn’t shift because voltage dropped below 12 volts on start battery...fly-by-wire is also very sensitive to voltage drop

I’d left my VFH radio on all night. When leaving Bamfield harbor, I knew the house battery was in a weakened state because the wipers were sluggish. But I figured my Suzuki alternator would juice the house battery back up while I was underway to the fishing grounds. It would of, eventually, but once the ACR saw the voltage imbalance, it started replenishing the house battery voltage.... unfortunately, that was at the expense of the start battery voltage.

Boom, I lost fly-by-wire once out of the harbor. I was adrift. I finally got squared away letting my kicker run with the Suzuki which got all the voltages back to where they should be. Just something to keep in mind when installing ACR....it works fine...until it doesn’t

 

[Baxter]

Good notes from everyone. Thanks for the feedback.

As for the chart, I discovered it recently as well. Realize now that 2ga is way overkill. Will likely go with 8. Maybe 6. But from the looks of it 10 may even be fine. We shall see.

I did manage to get my negative terminal cleaned up today. It’s a start! Before and after in the pics.

I want to replace the terminals on all those wires too. They don’t look great, but I didn’t have the hardware. Will be picking up new ends and cleaning it up further probabkybtkmorrow

 

[bigdogg1]

Actually, thinking this may be the answer, battery to this fuse block (https://www.bluesea.com/products/5025/ST_Blade_Fuse_Block_-_6_Circuits_with_Negative_Bus_and_Cover) , then to accessories
As Zurk suggested:

battery > 2 ga > Fuse Block > 12 ga > 'accessory'

Some great answers in this thread. BTW, why not use the Blue Sea 12 circuit block? Only a slightly larger footprint not overly costly and doubles your potential lines.

Where are you located?

 

[Baxter]

Some great answers in this thread. BTW, why not use the Blue Sea 12 circuit block? Only a slightly larger footprint not overly costly and doubles your potential lines.

Where are you located?

I’m in Comox. May go that route. Undecided exactly just yet. Cleaning up other wiring then will tackle the fuse block.

 

[zurk]

2 guage seems overkill until you decide to put a 55A bow mount trolling motor in front of your boat.
also its a kingfisher. you can literally fish two guage from back to front and still have enough left over for another 3 2 guage runs.

 

[Baxter]

2 guage seems overkill until you decide to put a 55A bow mount trolling motor in front of your boat.
also its a kingfisher. you can literally fish two guage from back to front and still have enough left over for another 3 2 guage runs.

Ya, I was planning on adding 6 more chart plotters, 3 electric trolling motors, two big screens, and a forced air electric furnace. So 4 2ga runs may be necessary.

 

[casper5280]

I went with the Blue Seas fuse blocks, 1 up front and another 2 in the back. One fuse block in back is 24 hour power the other is switched. The 24 hour is bilge pumps and kicker so I can tilt kicker when sitting on trailer and LED lights that are controlled by a key fob for dark morning walking down to boat that can be turned on before getting to boat. 10 gauge wire to all run though a Blue Seas ACR.

 

[bigdogg1]

Ya, I was planning on adding 6 more chart plotters, 3 electric trolling motors, two big screens, and a forced air electric furnace. So 4 2ga runs may be necessary.

 

[Corey_lax]

I have 6 ga running from my switch to a bus bar at the helm. Downriggers are direct to battery 2. The kicker charger is direct to battery 2. 18’ boat

 

[Corey_lax]

Also, use tinned wire for marine items. Not regular 12v wiring.

 

[prodjsaig]

Good notes from everyone. Thanks for the feedback.

As for the chart, I discovered it recently as well. Realize now that 2ga is way overkill. Will likely go with 8. Maybe 6. But from the looks of it 10 may even be fine. We shall see.

I did manage to get my negative terminal cleaned up today. It’s a start! Before and after in the pics.

I want to replace the terminals on all those wires too. They don’t look great, but I didn’t have the hardware. Will be picking up new ends and cleaning it up further probabkybtkmorrow

how long is the run to the finder?

 

[prodjsaig]

hold on here whats the length of the run.

 

[prodjsaig]

i would use 4 gauge to the helm if its 18feet. depends on amps say 50 amps. 4 gauge. sound system 2 gauge 18' x2 for the negative 36'. how many amps

 

[Baxter]

how long is the run to the finder?

Haven’t measured but somewhere around 12’ or so.

 

[Baxter]

hold on here whats the length of the run.

Total run from switch to helm is approximately 12 to 14’.
I haven’t measured it just yet. Could be as long as 16’ but would be surprised

I have a handy chart now to assess gauge vs load.

 

[prodjsaig]

4 gauge for 50 amp. use 2 gauge is adding amplifier speakers. wire is not bad harbour chandler has free shipping and tinned wire. I ran 18' with 2 awg to blue seas 12 circuit fuse block.