Category Archives: Boat Wiring

test post


this is a test post about one of my products

Memory Issue

Hi Kevin,

I just purchased a 1986 Chaparral 235xlc, from a guy in Maryland. It was a salt water boat powered buy a 350 Chevrolet with a SEI (alpha) outdrive.

Alpine stereo

The problem...

I put a new battery into the boat, put it into the water, running for about a hour max. Took boat home, checked battery voltage...12.28 volts. Went back a few days later, battery was stone dead...4.3 volts.

Upon looking in the bilge area, I see that a lot of the boat wiring is just cut off, with no idea of to where they were coming from. I also noticed that there is five extra small wires attached to the battery terminal. I would like to trace their locations and remove them if possible.

To solve the battery drain, I added a battery cut-out switch to the boat.

Is there any way of getting a wiring diagram for my boat? Any idea what would be draining the battery in my boat?

Thank for the help,


Your best bet for a wiring diagram would be directly from Chaparral. Unfortunately, the problem probably has nothing to do with the original wiring.

The usual suspect for a battery drain is a stereo memory. I would trace this first. After running for an hour the battery voltage should be well above 12.28 volts.

It is possible that the alternator is not functioning properly. It may not be charging and also creating the draw down when the engine is off.

Hope this helps

Waterproof Switch Panels?

Hi Ez Guys,

I am building a wooden runabout and am at the stage where I need a boat wiring harness. I have a few questions concerning your snap-together systems...

EzAcDc marine electrical switch panel
  • Are your panels waterproof?
  • Are any of your panels black?
  • Are there other labels available for the breakers?

Thanks for your help.


With the breaker boots, the fronts of our panels are waterproof, but none of the panels are available in black. All of our snap together marine electrical switch panels come with the following switch caps:

  • Horn
  • Nav/Anc
  • Bilge Pump
  • Livewell Pump
  • Courtesy Lights
  • Docking Lights
  • Stereo
  • (3) Accessories.

The horn and nav/anc come pre-installed on their corresponding switches. All others are simply snapped on when you do your installation.

We do not have any other printed switch caps, but we do have blank one's that we would be happy to send at no charge.

Hope this helps.


Shore Power Battery Charging

Dear Boat Wiring Guys,

I am looking at your complete shore power system and it seems to be perfect for my boat.

Catalina 27

Could you please me if this is a 30 amp system or a 15 amp system?

Also, Does your unit come with some connection to the battery so that the batteries are charging while pluged into the shore power? I want to be charging my boat batteries while I'm plugged into shore power.

I have a 27 Catalina sailboat that has an outboard motor. The only thing the batteries provide power to are the stereo, interior cabin lights, running lights, ship to shore radio, etc. It does not power the outboard.



It is actually a 20 amp system.

The inlet is a standard Marinco 30 amp inlet that works with any 30 amp twist lock cordset. The main breaker is a 20 amp dual pole. All outlets and wiring are rated at 20 amps or higher.

To charge your batteries, simply plug in a marine grade battery charger to either one of the remote outlets or one of the outlets on the back of the panel. When the shore power cord is connected, the battery charger will be charging.

The battery charger is not included.

Hope this helps,


Boat Battery Charger Plug

Dear Ez,

I am going to be adding shore power to my boat wiring and I think your Complete Shore Power System will be perfect for my setup.

My question is about adding a battery charger after I install your product.

Boat battery charger plug

I’m planning on installing to add a ProNautic 1220P Series 20 amp on board dry mount battery charger on my boat. But, it does not come with an AC power cord with a traditional three prong plug. How would I connect it to your system given it only has traditional power outlets? Do you make an adapter?

My goal is to be able to run the DC system (lights, stereo) off the charger which will be hooked up to my new AC power source… everywhere I’m reading says that a dry mount charger is the way to go but these typically do not come with wiring that has the three prong plug the way a wet mount charger does.

Thanks for your help.


The simplest solution is to use an AC pigtail style cord when you connect AC to your charger

It will have a three prong plug on one end and bare wares on the other. If you cannot locate one at your local home improvement store, this is basically a 16 AWG extension cord with the female end cut off. With this cord, the charger can be hard wired at the charger and simply plug into the your new shore power outlets.

Hope this helps, Kevin

Switch Switches

Good morning Ez,

Blue Seas Boat Battery Switches

I’m interested in installing one of your Smart Boat Battery Switch Systems. Could you please tell me if it would work with my current battery switch? I have a dual batter that was built by Blue Sea Systems. It is their model# 9001E.



The system would replace your existing 9001 switch, but the change comes with a big advantage.

Instead of having a 1/2/both/off switch you would have an On/Off with the ability to emergency combine. This means that you can still start the boat if you should run down the starting battery. But, by losing the "BOTH" option from the switch, it makes running that battery down much harder to do.

Hope this helps,


Boat Battery Isolator or VSR?


My boat wiring question is simple.

Voltage Sensitive Relay or a Battery Isolator?

I have a 2004 PolarKraft 165SC with a single 50 HP Yamaha 2 stroke. I also use a Guest 2-bank onboard AC changer. I really hate having to drag my accessory boat battery out to recharge it when away for a two week vacation in Canada. so one or the other seems to be something I could really use.

Boat battery isolator and VSR

The VSR seems to be a more complex solution - at least from what I've seen on the net. The boat battery isolator seems to do the same thing quite simply.

I've seen some isolators that have large heat sinks and some that don't (which are smaller and more expensive - but reviewers say they are better and it's worth it..) I think I just saw something about an ACR - is that another option?

Can you offer any advice ?? I've read a lot of your online advice and I'm still not clear on this. I think I read that this idea is not applicable to my boat? Also saw a nice diagram of the wiring, but you used both a VSR and an Isolator. I'm confused.

Have I oversimplified the issue/decision, or perhaps I've missed something and it's more complicated.


I would definitely use a voltage sensitive relay system over an isolator in your application.

The VSR would connect between you battery's positive posts with a ground cable connecting the negatives. When either battery goes above 13.7 volts the VSR engages and both batteries are charging.

If you used an isolator you would need to first isolate the alternator output wire from you outboard engine. Usually this is difficult. It is not just the positive battery cable. Since the alternator on the outboard is connected directly to the battery, if you added an isolator you would need to account for the voltage drop induced by the isolator. This could be as much as 1 volt and will cause your batteries to not fully charge.

An isolator is much easier to install on an inboard engine. The alternator wiring is much easier to access.

As for the confusion in terminology, BEP Marine calls their device a VSR. Blue Seas call the device an ACR. Both do the same thing and connect the same way.

Hope this helps

Shore Power Outlets

Hi Ez,

Last summer, I bought and installed your simple snap together shore power kit on my 24' Bayliner boat. It works and looks great.

Bayliner 24 Trophy

For the upcoming season, I need one of your remote outlets that snap into the back of the breaker box.

What is a safe length for this remote mount? I have only a 15 amp system. The outlet will mount in top of galley counter for miscellaneous applications. I also want to run another outlet about 8 ft to use for wall mount small flat screen. 

Was looking for a link to what you have ready to ship. Or do you need to special order them?



We don't list the remote outlets as a separate item, but we often sell them.

They come with the black mating plug that matches the one's on the back of your panel on one end and an outlet on the other end. If you want 2 outlets, the second one will plug into the first one.

The standard length is 15' between the plug and the outlet.

Please let us know how you would like to proceed and we can deal with the order via email or phone.

Thank you,


LED Navigation Light Upgrade

Hey guys,

I have a quick boat wiring question.

Glastron 27 boat

I currently own a 2007 Glastron 27 footer and want to upgrade all of my navigation lights to LED. While I'm at it, I'm going to add a few others as the boat is currently a little dark.

Will I be easily able to connect your LED navigation lights to the existing switch on my helm to turn them on and off? Or, do i need some special switches to make this work?



No special switches are necessary.

Your current lights will have two wires and so will your new lights. The only thing to keep in mind is that unlike the lights you are replacing, LED lights are polarity sensitive. This means that when you connect them they will not work unless the positive wire is connected to the correct wire.

Our LED lights also have reverse polarity protection. So, they will simply not turn on if hooked up backwards as compared to burning up like some other lights.

Hope this helps.


Ground Game

Boat Wiring Guy,

Been at this for a few hours today and am frustrated.

Humminbird Fishfinder

Bought a new Hummingbird fish/depth finder, un-installed the old one and unplugged only the two places (one power, one ground) from the “power switch” on the dash. Installed new one (same brand but had to run all new wires because the new one has GPS), plugged the new wires to the SAME exact places the old ones were........nothing, I got nothing!!

Now the craziness begins...

The windshield wipers no longer work but when I hit the windshield wiper switch. The gas gauge works with the key off. When I hit the switch for the depth finder, nothing - except that the bilge switch light comes on. I get more lights to the switches with the ignition key off than on. I can only get the light of the depth finder switch to come on if the boat ignition key is in the off position. No matter what I do I cannot get the wipers to work anymore. What the heck?

All I did was unplug the wire for the depth finder switch, how can that have any affect on all the rest of this mess? I can assure you that I unplugged the old and plugged in the new to the EXACT same contact points.

Thanks in advance for any advice you can muster up.


The ground connection for your helm is bad. It was either inadvertently knocked off or it may just be making a poor contact. All of your symptoms point to this.

The bad connection may not be obvious. It may be a corroded connector.

Try running a test wire from the battery negative to any ground under your helm.

This will solve your problem


Hi Kevin,

We ran a test ground wire from the battery directly to a ground point under the dash and everything works like it is supposed to. So, yes, that appears to be the problem, but, how do we find the trouble spot?

We traced lines from each battery, nothing amiss. We checked the wires under the dash for all the switches, nothing amiss.

Any ideas where this mystery ground is that is giving us fits?

Thanks again.


You may never find the problem. It might just be easier to run a new wire through the boat and forget about finding the bad connection.



Are you saying we could just run a line from the negative post on one of the boat batteries to the ground post under the dash? Will that cause problems with the rest of the systems?

What you are suggesting sounds a lot like our test wire. It goes from the wing nut on the negative side of the boat battery and runs up to the spade under the dash near the switches.


If you cannot find the problem with the current wire, you almost have no other choice but to run a new wire.

This is a very common solution to the problem that you are having. Although, if you use this technique too many times, you will end up with a huge mess.


Hi Kevin,

We wanted to thank you so very much for helping us solve our boat wiring issue.

We ran the new ground wire today, hooked up the new depth finder and new CB radio and EVERYTHING works perfectly.

So glad to have found your website and "made contact" with such a wiring expert!!