Notices
The Boating Forum

Tips on re-wiring boat electrical

Old 01-20-2018, 12:05 PM
  #1  
Senior Member
Thread Starter
 
Join Date: Nov 2017
Location: South Florida
Posts: 403
Received 55 Likes on 34 Posts
Default Tips on re-wiring boat electrical

I have a 2002 Sea Fox 230 CC with a Mercury 150. It has a dual battery setup with a Perko (1-2-BOTH-OFF) switch and both batteries at the stern. Battery 1 on port side and Battery 2 on starboard side.

I just installed a new Perko switch, and all new battery cables. The only thing connected to the Perko switch are the big 4-gauge cables for starting.

Everything else is hot wired to Battery #2, which in some way makes it up to the console switches, or directly to the accessory itself.

I want to run all new wiring at some point. I figured 14-gauge?

These are all the accessories. What would be the most sensible way to wire? Should I still keep everything off of battery #2? I'm not 100% sure how it's currently wired. Just know theres a handful of positive and negative small gauge wires going to battery 2. About 4-5 pairs.

Panel switches with circuit breakers:
Nav lights (3-way switch, On/Off/Anchor)
Bilge Pump (2-way switch, On = automatic float switch, and off)
Aerator (does not work)
6.0 GPM Saltwater washdown pump at stern
4.0 GPM Freshwater washdown pump inside center console
Horn

Accessories with in-line fuses (hot):
VHF radio
Stereo
Small spotlight on T-top
Depth/Fish finder
Old 01-20-2018, 12:13 PM
  #2  
Senior Member
Thread Starter
 
Join Date: Nov 2017
Location: South Florida
Posts: 403
Received 55 Likes on 34 Posts
Default

Battery is located beneath that hatch, on their respective sides.







I don't like the idea of multiple cables grounding or getting power from the tachometer, or is that normal? It appears some gauges are daisy chained, which I guess makes sense, or using the tachometer post just as a ground like the cigarette lighter shown. The tachometer currently does not work and am in the process of troubleshooting that. The loose wires came off of the tachometer.




I believe the previous owner installed this, as it doesn't seem factory. It's a small junction box that would use barrel fuses. There are no fuses installed, but instead has a bunch of ground wires on one side, and hot accessory wires on the other side. As mentioned above, all accessories either have their own inline fuse, or a circuit breaker if panel switched.

Old 01-20-2018, 12:22 PM
  #3  
Senior Member
 
Join Date: Mar 2017
Posts: 162
Likes: 0
Received 11 Likes on 9 Posts
Default

One tip on connections. Many people like to weatherproof connections with silicon RTV. Unfortunately, when RTV sets, it gives off ascorbic acid (vinegar), which corrodes copper, leading to high resistance connections. If you wish to use it, solder the connector on to the wire first, then apply the RTV.
On wiring, I would use a large conductor, at least 10 gauge, for a common instrument bus ground, possibly one per battery in your case. All connections should trace themselves back to this ground. I also like a lightning rod with a separate 10 ga conductor to the water.
Old 01-20-2018, 12:39 PM
  #4  
Senior Member
Thread Starter
 
Join Date: Nov 2017
Location: South Florida
Posts: 403
Received 55 Likes on 34 Posts
Default

Originally Posted by BruceEdward View Post
One tip on connections. Many people like to weatherproof connections with silicon RTV. Unfortunately, when RTV sets, it gives off ascorbic acid (vinegar), which corrodes copper, leading to high resistance connections. If you wish to use it, solder the connector on to the wire first, then apply the RTV.
On wiring, I would use a large conductor, at least 10 gauge, for a common instrument bus ground, possibly one per battery in your case. All connections should trace themselves back to this ground. I also like a lightning rod with a separate 10 ga conductor to the water.
Thanks for the reply. That's kind of what I was thinking actually. I like the idea of having a heavier common ground, as I have had grounding issues in the past.

Would you run one ground wire from each battery to a single post in the console?
Old 01-20-2018, 12:40 PM
  #5  
Admirals Club Admiral's Club Member
 
Join Date: Apr 2014
Location: Apollo Beach, FL
Posts: 3,719
Received 1,234 Likes on 607 Posts
Default

Go to Bluesea.com and look at their schematics, great people to deal with too.
Old 01-20-2018, 01:20 PM
  #6  
Senior Member
 
Join Date: Mar 2017
Posts: 162
Likes: 0
Received 11 Likes on 9 Posts
Default

No, I would tie all three batteries' negative terminals locally to your common ground. You don't want one "floating" off of the ground potential of another due to a high resistance connection, most probably at a battery terminal. That single common then becomes your ship common ground, run to the console equipment, and any remote devices that use a ground. This avoids instrumentation problems, especially if a light or sensor remote from the console has the potential to "see" a floating ground potential, different from the console.
Old 01-20-2018, 02:56 PM
  #7  
Senior Member
Thread Starter
 
Join Date: Nov 2017
Location: South Florida
Posts: 403
Received 55 Likes on 34 Posts
Default

This is the current battery wiring diagram. Not shown, but battery #2 is the one with small gauge accessory wires attached to both negative and positive terminals.


Old 01-20-2018, 03:14 PM
  #8  
Senior Member
 
Join Date: May 2017
Posts: 148
Received 36 Likes on 23 Posts
Default

Never seen a switch mounted in the open like that. Personally, I'd change that ASAP.
Old 01-20-2018, 03:22 PM
  #9  
Senior Member
 
Join Date: Jul 2011
Posts: 7,715
Received 1,349 Likes on 1,040 Posts
Default

Originally Posted by rrhyne View Post
Never seen a switch mounted in the open like that. Personally, I'd change that ASAP.
Interesting, had a thread on that recently:

Battery Switch and Charger plug on outside of transom

I certainly wouldn't do it with a Perko; might end up like this:

Name:  11c8q4i.jpg
Views: 5216
Size:  95.2 KB
Old 01-20-2018, 04:19 PM
  #10  
Senior Member
Thread Starter
 
Join Date: Nov 2017
Location: South Florida
Posts: 403
Received 55 Likes on 34 Posts
Default

To be honest, it hasn't caused a problem in 10 years. The only reason I replaced it is because we had one lying around, and the knob rotates smoother. It was like that when my father bought the boat in 2008.

Didn't bother to disassemble the old one before we threw it away, but the terminals didn't look bad.
Old 01-20-2018, 05:14 PM
  #11  
Senior MemberCaptains Club MemberPLEDGER
 
Join Date: Feb 2001
Location: SE LA
Posts: 5,526
Received 492 Likes on 237 Posts
Default

I read these books several years ago. They really helped me design my first electrical system. Since then have completely redesigned electrical systems in 5 or 6 boats.

The 12-Volt Bible for Boats (my favorite)

Boatowner's Illustrated Electrical Handbook

Replacing Your Boat's Electrical System
Old 01-20-2018, 05:20 PM
  #12  
Senior Member
 
Join Date: Sep 2004
Location: San Francisco Bay Area
Posts: 1,078
Received 118 Likes on 79 Posts
Default

Originally Posted by Sonic04GT View Post
This is the current battery wiring diagram. Not shown, but battery #2 is the one with small gauge accessory wires attached to both negative and positive terminals.


This is what I would do, space permitting:

NEG: You have connected all the battery negative terminals together. Now connect a 8 or 10 gage black wire from a battery terminal to a buss bar mounted on the inside transom. To this buss bar you will also connect a 10 gage black wire that runs to your helm, the negative leads for your washdown pump, bait pump, trim tabs, any component that is mounted in the stern. This eliminates longer negative wires running to/from the helm and reduces wire mess.

The negative wire end at the helm will also connect to a buss bar or Blue Seas fuse panel mounted inside the helm. Some Blue Seas fuse panels also provide for NEG connections.

POS: I would use the pos common lug of the battery switch as your starting point on the positive circuit. With the battery switch off, there is no power running anywhere in your boat (with the exception of the auto bilge circuit. That positive lead needs to connect directly to a battery. The negative lead can connect to the neg buss bar).

If you need POS distribution at the transom (downriggers or separate fishfinder for examples), you can add a buss bar here too. Otherwise, run a 8 or 10 red wire from the "common" lug to your helm. This run should be protected with a 40+ in-line circuit breaker. At your helm, I would use a Blue Seas panel with integrated plug in fuses. The fused circuits will include the cig lighter, and any electronics with an off/on switch. Your dash switches have their own C/Bs. Those can be powered in a daisy chain fashion (from C/B to C/B to C/B...) and connected to the non-fused side of the Blue Seas panel.

This is the panel I'm talking about: https://www.bluesea.com/products/502..._Bus_and_Cover
Old 01-20-2018, 05:42 PM
  #13  
Senior Member
 
Join Date: Mar 2017
Posts: 162
Likes: 0
Received 11 Likes on 9 Posts
Default

The reason for my direction is as follows: Consider what happens if one of the negative battery terminals is corroded, creating a higher resistance connection, and the load is dedicated to that battery. If there is a voltage drop across the terminal connection of that battery to the negative terminal (voltage drop = current x resistance), the ground potential will "float" off of true ground. You want to get your 10 ga ground bus wire as physically and electrically close to both negative terminals as possible, and keep them clean. The ground system wil take care of itself if you do this. WD40 is really helpful in this respect.
Old 01-20-2018, 06:14 PM
  #14  
Senior Member
 
Join Date: Aug 2016
Posts: 987
Received 1,132 Likes on 630 Posts
Default

I had a 2007 sea fox 226 bay boat. The tachometer fried, literally. The inside of the bezel was discolored from smoke. Everything in the instrument panel went dead, which included gauges and switches. The ground wire in the tach had lost connection somehow. A new ground wire was ran to the panel circumventing the tach and everything else in the panel worked again. My guages were silver and the tach had 4 idiot lights in it. I don't know why it was wired that way or if it had to be wired that way but it was.
Old 01-26-2018, 09:13 PM
  #15  
Senior Member
Thread Starter
 
Join Date: Nov 2017
Location: South Florida
Posts: 403
Received 55 Likes on 34 Posts
Default

I purchased one of these Blue Sea Fuse Blocks. How do I determine what size breaker to use between the battery and the fuse block as mentioned in this document?

I could not find that table mentioned. I see above a7ewizard mentioned 40+.

http://assets.bluesea.com/files/reso...-5026_5031.pdf

The only items I can think of right now that will go to this fuse block (everything else has their individual push-to-reset breakers with switches as shown in the picture) are:
VHF Radio
Stereo
Fish Finder
Small Rear incandescent light
Front 126watt light bar
I need to see how the cigarette lighter is currently wired, but probably that too

Max for the block is 100AMP, max per circuit 30AMP, per the manufacturer's product page.
https://www.bluesea.com/products/502..._Bus_and_Cover


This diagram shows a 30AMP but I don't know the source, as it seems fairly generic.


Old 01-26-2018, 09:16 PM
  #16  
Senior Member
Thread Starter
 
Join Date: Nov 2017
Location: South Florida
Posts: 403
Received 55 Likes on 34 Posts
Default

Originally Posted by BruceEdward View Post
The reason for my direction is as follows: Consider what happens if one of the negative battery terminals is corroded, creating a higher resistance connection, and the load is dedicated to that battery. If there is a voltage drop across the terminal connection of that battery to the negative terminal (voltage drop = current x resistance), the ground potential will "float" off of true ground. You want to get your 10 ga ground bus wire as physically and electrically close to both negative terminals as possible, and keep them clean. The ground system wil take care of itself if you do this. WD40 is really helpful in this respect.
Thank you, I will keep that in mind.

Originally Posted by R Days View Post
I had a 2007 sea fox 226 bay boat. The tachometer fried, literally. The inside of the bezel was discolored from smoke. Everything in the instrument panel went dead, which included gauges and switches. The ground wire in the tach had lost connection somehow. A new ground wire was ran to the panel circumventing the tach and everything else in the panel worked again. My guages were silver and the tach had 4 idiot lights in it. I don't know why it was wired that way or if it had to be wired that way but it was.
Ouch, that's no bueno. I really need to spend the time one of these days and trace each wire to see how things are routed through the tach.
Old 01-27-2018, 03:41 AM
  #17  
Senior Member
 
Join Date: Feb 2015
Posts: 3,465
Likes: 0
Received 134 Likes on 111 Posts
Default

The diagram shows a 30amp circuit breaker between the battery and fuse block which should be OK for your application unless you use the cigarette lighter with everything else on. (heating elements draw some serious current). Best way to determine the fuse/breaker capacity required is to sum the current draw of all loads from equipment specs and add 10-15%. Best, easiest, least expensive and most reliable way to protect that circuit would be a fuse holder rated for the load IMHO; you can size fuse to match load closely and increase size if necessary to avoid nuisance tripping.

Pictures indicate your boat was wired with automotive wire and terminal connectors for least cost and convenience not reliable service nor durability. If you want to rewire the boat then inspect every cable, wire and terminal for corrosion and replace all non marine wire, terminals, terminal blocks, switches, etc. with wire and/or cable and heat shrink compression terminals rated for marine use. Wire, cable and heat shrink terminals (heat shrink tubing sleeves for battery cables) rated for marine use are more expensive but will protect your electrical system from marine service corrosion and vibration are less expensive and aggravating in the long run and cheap insurance. The battery switch is fully exposed to weather and splash well and almost guaranteed to fail. I would also move batteries and switch under/into the console if at all possible for protection from the bilge and elements and better weight distribution.

Make a wiring diagram (graph paper helps) with length of each and every wire noted and use wire sizing tool at blue seas web site or similar to size wire and cable on circuits for full load (i.e. <5% voltage drop with everything connected to that circuit turned on). Most boats are wired with a common negative buss bar connected to all batteries and mounted as close as possible to loads to minimize the spaghetti effect. A fused switch panel for marine applications also reduces wire runs, provides appropriately sized fuse protection for each/every circuit and better/easier serviceability.

Last edited by LeakinLena; 01-27-2018 at 04:08 AM.
Likes:
Old 01-27-2018, 07:04 PM
  #18  
Senior Member
Thread Starter
 
Join Date: Nov 2017
Location: South Florida
Posts: 403
Received 55 Likes on 34 Posts
Default

Originally Posted by LeakinLena View Post
The diagram shows a 30amp circuit breaker between the battery and fuse block which should be OK for your application unless you use the cigarette lighter with everything else on. (heating elements draw some serious current). Best way to determine the fuse/breaker capacity required is to sum the current draw of all loads from equipment specs and add 10-15%. Best, easiest, least expensive and most reliable way to protect that circuit would be a fuse holder rated for the load IMHO; you can size fuse to match load closely and increase size if necessary to avoid nuisance tripping.

Pictures indicate your boat was wired with automotive wire and terminal connectors for least cost and convenience not reliable service nor durability. If you want to rewire the boat then inspect every cable, wire and terminal for corrosion and replace all non marine wire, terminals, terminal blocks, switches, etc. with wire and/or cable and heat shrink compression terminals rated for marine use. Wire, cable and heat shrink terminals (heat shrink tubing sleeves for battery cables) rated for marine use are more expensive but will protect your electrical system from marine service corrosion and vibration are less expensive and aggravating in the long run and cheap insurance. The battery switch is fully exposed to weather and splash well and almost guaranteed to fail. I would also move batteries and switch under/into the console if at all possible for protection from the bilge and elements and better weight distribution.

Make a wiring diagram (graph paper helps) with length of each and every wire noted and use wire sizing tool at blue seas web site or similar to size wire and cable on circuits for full load (i.e. <5% voltage drop with everything connected to that circuit turned on). Most boats are wired with a common negative buss bar connected to all batteries and mounted as close as possible to loads to minimize the spaghetti effect. A fused switch panel for marine applications also reduces wire runs, provides appropriately sized fuse protection for each/every circuit and better/easier serviceability.
Thanks a lot for the response. I'll take all of that into consideration when I start re-wiring next month.
Old 01-28-2018, 01:11 AM
  #19  
Senior Member
 
Join Date: Dec 2015
Location: Southeast Alaska
Posts: 187
Likes: 0
Received 3 Likes on 1 Post
Default

Originally Posted by LeakinLena View Post
The diagram shows a 30amp circuit breaker between the battery and fuse block which should be OK for your application unless you use the cigarette lighter with everything else on. (heating elements draw some serious current). Best way to determine the fuse/breaker capacity required is to sum the current draw of all loads from equipment specs and add 10-15%. Best, easiest, least expensive and most reliable way to protect that circuit would be a fuse holder rated for the load IMHO; you can size fuse to match load closely and increase size if necessary to avoid nuisance tripping.

Pictures indicate your boat was wired with automotive wire and terminal connectors for least cost and convenience not reliable service nor durability. If you want to rewire the boat then inspect every cable, wire and terminal for corrosion and replace all non marine wire, terminals, terminal blocks, switches, etc. with wire and/or cable and heat shrink compression terminals rated for marine use. Wire, cable and heat shrink terminals (heat shrink tubing sleeves for battery cables) rated for marine use are more expensive but will protect your electrical system from marine service corrosion and vibration are less expensive and aggravating in the long run and cheap insurance. The battery switch is fully exposed to weather and splash well and almost guaranteed to fail. I would also move batteries and switch under/into the console if at all possible for protection from the bilge and elements and better weight distribution.

Make a wiring diagram (graph paper helps) with length of each and every wire noted and use wire sizing tool at blue seas web site or similar to size wire and cable on circuits for full load (i.e. <5% voltage drop with everything connected to that circuit turned on). Most boats are wired with a common negative buss bar connected to all batteries and mounted as close as possible to loads to minimize the spaghetti effect. A fused switch panel for marine applications also reduces wire runs, provides appropriately sized fuse protection for each/every circuit and better/easier serviceability.
Hello,
I also was planning to move two batteries from transom to cabin.
So if my batteries are both up front, I would run the 10 gauge pos and neg cable back to a buss bar for each for my bilge,washdown,trim tabs . Correct?
Also the verado has a few fused components like power trim and power steering, are those allowed to be on a buss bar as well?

god Bless and happy boating
Old 01-28-2018, 04:37 AM
  #20  
Senior Member
 
Join Date: Feb 2015
Posts: 3,465
Likes: 0
Received 134 Likes on 111 Posts
Default

Originally Posted by Proline31 View Post
Hello,
I also was planning to move two batteries from transom to cabin.
So if my batteries are both up front, I would run the 10 gauge pos and neg cable back to a buss bar for each for my bilge,washdown,trim tabs . Correct?
Also the verado has a few fused components like power trim and power steering, are those allowed to be on a buss bar as well?

god Bless and happy boating
Power for tilt and trim motor is normally carried through battery cables and activated by a magnetic solenoid switch with OEM engine wiring. Trim tabs and power steering are usually wired on dedicated circuits; see trim tab and power steering OEM installation instructions for wire size recommendations or use current draw specified and select wire size accordingly (http://circuitwizard.bluesea.com/).

Moving batteries from stern to console requires a dry well ventilated location where batteries can be securely fastened (significantly more up and down motion forward than at the stern). Depending on configuration and how well boat electrical system is currently installed and maintained moving batteries forward may (not) also require a significant amount of (re)wiring for accessories, pumps, trim tabs, power steering, etc. I would be inclined to leave batteries in OEM designed spaces dedicated for the purpose if well ventilated, dry and secure regardless of location unless exposure to elements or water, serviceability and/or reliability are poor (e.g. mounted in bilge). Another consideration is you will most likely need new longer battery cables and terminal connectors rated for marine use. Use a tape measure and/or extension cord to find the correct cable lengths on the boat and add appropriate fudge factor for turns, terminals at battery switches, etc. Color coded (red and black) custom length cables one size larger than recommended with battery post terminals and lug terminals sized to match engine and switch(es) connectors with heat shrink tubing at all terminal ends and assembled by the cable supplier is money well spent and cheap insurance.

It’’s a lot easier to inspect, service and operate fuses, busses, switches, terminals, etc at console than digging around in the bilge or stern compartment (especially underway) so all should be mounted in/at console whenever possible IMHO. Some exceptions are bilge, live well and wash down pumps, etc. where relatively short length of OEM wire makes it sensible to mount a terminal block high in the bilge or a stern compartment with fork connectors on load for easier service/replacement then extend circuit wiring forward to switch and negative buss with appropriate size wire (heat shrink male/female spade or bullet connectors also work OK if it’s not practicable or inconvenient to gather wiring at stern busses).

A fused switch panel at the console for all accessories with a negative buss nearby allows you to tailor fuse and wiring sizes to individual loads and gives independent control and protection for each circuit. It requires some additional wire but avoids electrical interaction between different accessories and troubleshooting and service are easier. Some accessories current draw may exceed the carrying capacity of an accessory fuse panel and will require dedicated wiring, switches or fuses but are often functions you operate frequently with independent switches readily available at the helm (e.g. trim tabs, autopilot) or not at all (e.g. power steering) and not appropriate to be mixed into a multi switch fused panel.

Last edited by LeakinLena; 01-28-2018 at 05:16 AM.

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright © 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.