Easy Ac/Dc attempts to answer your questions about boat wiring and marine electrical techniques, concepts, and products. We get lots of mail from folks in mid-project or who are just curious about their boat’s electrical setup.

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Hello,

I purchased the VSR Smart Battery Switch from your partners at EzAcDc and now I am a tad bit confused. I removed my old battery switch, which had a lead from the Starter which is tied into the alternator.

The old switch was between the battery and the starter on that red wire, then it branched out to the batteries and both batteries went to ground. Simple.

Looking at the drawing that came with the system, I’m confused as to where the “charging” feed comes in? I’m assuming that is the left side of the diagram indicated as the engine Positive Cable. However I’m not sure where to hook up the outbound side into my boat harness Ala boat harness ground and boat harness power. Perhaps I got the wrong diagram?

Thanks so much for the help!
Tim

Hi Tim,

I’m sorry for the confusion.

Your 3.0L engine’s charging circuit is fed to the cranking battery through your engine start cable. The Orange alternator output wire runs from the alternator to the starter. It is connected to the same lug on the starter as the engine positive battery cable.

Your engine negative battery cable and your boat harness ground will both connect to the ground bus that came with your kit. Your boat accessory harness positive wire will connect to the back of the battery switch to the same terminal as one of the VSR wires.

If all of the accessories on your marine electrical system are powered up through the red/purple power lead that runs from your engine up to your dash, you will need to run a separate power wire from your new battery switch to the fuse block/breaker panel to separate these two circuits. Add circuit protection at the battery switch to protect this new wire.

Please let me know if you have any questions,

Kevin

Kevin,

Thanks for the response.

Just so I get this right

1. The red of the start lug (which also has the alternator orange wire on it) would attach to Lug number 1 on the switch.
2. Can I assume since the harness is already grounded that i don’t have to mess with grounding here?
3. Finally the red/purple. You’re saying to just disconnect the red/purple at the 20 amp fuse (page 5) and run a new wire from the lug into that fuse?

Thanks

Tim

Hi Tim,

You are correct on the first two assumptions above.  

As for the third question about the red/purple, you will need to run a separate wire to power your fuse block. The Red/Purple in your engine harness that runs up to your helm provides power for your key switch and instruments. Do not disconnect this wire. You will want these items to be powered by the engine battery.

Your existing red/purple probably connects to a fuse panel at the helm. The ignition switch gets it’s power from this fuse panel also. Disconnect the red/purple from the fuse block and connect it to your ignition switch. There is usually some form of circuit protection on this boat wiring. Please use it. Run a new wire (10 awg at least) from LUG number 2 on the battery switch to the fuse block under your helm. Install circuit protection (40 to 50 amps) as close as possible to the battery switch.

I hope this helps. If you are not sure on how to connect the red/purple, send me some digital pictures of your helm fuse panel and I will mark them up.

Kevin

Kevin,

I need to change out the pump on my shower sump. I will need your help to rewire it.

The pump has two wires. What is the best way to stop the power to the pump? I do not see any breakers,fuses etc.

Thank you for any help.

Dan

Hi Dan,

If you cannot find the breaker, go back to boat wiring basics and disconnect the battery.

Kevin

Kevin

Thank you for your reply and patience.

This is my first cruiser. I have two “house” batteries and one for the motors. If I disconnect their grounds will I screw up any of the marine electrical system when I reconnect and need to reset any systems? (i.e.. motors,generator,computers,gps etc)

Dan

Hi Dan,

The pump runs on 12 volt DC and there is no real danger if you short out the wires.

Make the connection one wire at a time. The worst thing that will happen is you find out where the shower sump circuit protection is.

Kevin

Kevin,

We have three AFI wiper motors on our boat wiring. We have three switches and three fuses for the motors but they are all connected to the same circuit breaker.

Two of the wipers do not work at all and the third will come on sometimes but won’t stay on. The circuit breaker light stays on and the fuses are not burned out.

Are the motors getting the right amperage or any idea of what the problem might be?

Maureen

Hi Maureen,

Each wiper motor will three wires: Ground, On, and Park. If you are missing any of these wires, your wiper will not function properly.

1. I would inspect the wiper motor grounds first. This is the only wire that all three motors have in common. The metal case AFI wiper motors are grounded to one of the motor housing bolts. The plastic case AFI motors have an internal ground.
2. Next, check for constant 12v power to the park terminal on each wiper motor.
3. Finally, check for switched 12v power to the On termianl on each wiper motor.

If all the wiring is correct, then you wiper motors may be dead. Before replacing, I would do one last bench test with separate leads to the wiper motor.

Hope this helps,

Kevin

Hello Kevin,

My marine electrical system currently includes one maintenance free starting battery (Group 24) and one AGM maintenance free deep cycle battery (also Group 24). I have the Guest 2611A battery charger attached to these two batteries for charging at the dock.

I was considering putting in a second deep cycle battery to provide more accessory time while out on the water and my plan would be to configure the boat wiring to connect it to the other deep cycle battery ‘in parallel’.

Would my 2611A charger be capable to charging these three batteries?

Thank-you
John

Hi John,

YES, but it will take a very long time to completely recharge.

The 2611 only puts out five amps max on each leg. Two dead batteries connected to one of the legs will take close to 2 days to recharge. Guest makes excellent products, but you may want to consider one of their larger units for your marine electrical system.

Kevin

Kevin,

Thank you for your response.

Generally when our charger is on it has a couple of days between uses so I’m not as concerned about the time it would take to recharge. And I would think that making the 5-6 mile run back to the marina with the Switch in the “All” setting would give the batteries a bit of a charge from the alternator as well.

I just wanted to make sure there were no safety issues. So if I put a third battery (a deep cycle) in the boat and connect its positive to the other deep cycle’s positive with a jumper and similarly connect up their negative terminals – when I put the switch on “2” the accessories would pull from both deep cycles and, in theory, I would get more accessory time?

I guess I just want to see if I can get by with my current switch and charger or do I need a more robust switch and charger to have three batteries.

Thanks again (and I will make a contribution via PayPal)

John

Hi John,

Adding a third battery in parallel to your second is a very common boat wiring practice.

When you do this, make sure that you use cables that are at least as large as the largest cables that are currently used on the battery switch system.

Kevin

Kevin,

Thanks again.

I was hoping to get the cables this week and won’t have access to the boat before then so I may have to guess. Do you think four AWG would be safe for a basic speedboat (24’ Malibu Wakesetter)?

John

John,

It’s really funny that you should ask that!

I’m just finishing a downloadable Battery Cable Calculator. I’ll post it in the next day or two for all of our readers.

Kevin

Kevin,

I am installing the EzAcDc marine shore power system. Could you please clear something up for me?

Is it OK to have the AC and the DC panels in the same area as long as you don’t group the wires together?

I had read to keep the AC and DC apart in marine electrical systems, but I am not sure if that meant just to space wires apart so they don’t chafe through and connect systems or if they needed further separation.

Thanks.

Mike

Hi Mike,

Yes. It is OK to have both panels in the same area.

Per the American Boat and Yacht Council, if the AC system and DC system are on the same panel, then the AC system needs to have an enclosure to prevent accidental contact when you are working on the DC side. Even though it is not required, the EzAcDc Easy Add AC panel has rear safety enclosure.

When installing AC and DC boat wiring, it is a good practice to separate the AC and DC wiring because most AC HOT wires are black and most DC GROUND wires are black. Accidental swapping would be very dangerous.

I hope that this is helpful. Please let me know if you have any other questions about your project.

Kevin

Barbara writes on solar panel kits and 12 volt systems in her personal hobby blog, 12voltsolarpanels.net.  Her efforts are centered on helping people save energy using solar power to reduce CO2 emissions and energy dependency. And, to further those efforts, Barbara generously offered the following overview to those of us in the marine electrical community.

What’s solar power?

Solar energy is radiant energy which is produced by the sun. Every day the sun radiates, or sends out, an immense quantity of energy. The sun radiates more energy in a single second than people have used since the beginning of time!

The energy of the Sun derives from within the sun itself. Like other stars, the sun is a big ball of gases––mostly hydrogen and helium atoms.

The hydrogen atoms in the sun’s core combine to create helium and generate energy in a process called nuclear fusion.

During nuclear fusion, the sun’s extremely high pressure and temperature cause hydrogen atoms to come apart and their nuclei (the central cores of the atoms) to fuse or combine. Four hydrogen nuclei fuse to become one helium atom. But the helium atom contains less mass compared to four hydrogen atoms that fused. Some matter is lost during nuclear fusion. The lost matter is emitted into space as radiant energy.

It takes an incredible number of years for the energy in the sun’s core to make its way to the solar surface, and then just a little over eight minutes to travel the 93 million miles to earth. The solar energy travels to the earth…Please click here for Barbara’s complete article.

Kevin,

I bought a four-position switch to replace my four-position/four-terminal switch on my Mercury Marine 5.0 MPI’s boat wiring. 

The problem is the new switch has arrived and has six wires. The extra two say 5 and 6 position are for the battery and ignition – as shown in the attached picture.

Should I ignore these and cut the wires off or should I connect them to 1 and 4? 

Do I need a different switch?

Dan

Hi Dan,

This switch will work fine.

Ignore positions 5 and 6. They are internally connected to 1 and 4. You can either cut them off or tape them up.

Kevin

Kevin,

How do I install dual fuel guages on my boat wiring?

I want to add a second fuel guage on my boat’s upper flybridge helm station. There is an existing fuel guage in my lower helm station.

Thank you,

Mark

Hi Mark,

A fuel gauge needs three wires to function.

• Power
• Ground
• Signal.

For the first two, use your flybridge ignition as the power and ground the gauge at your flybridge.

For the signal use an ON-ON switch similar to this one from Carling to switch your fuel tank sending wire from your upper to lower station.

• Remove the existing sending wire (usually pink) from your gauge.
• Connect this wire to the center terminal on your switch.
• Run a new wire from the lower terminal on your new switch to your upper gauge.
• Run a second new wire from the upper terminal on your new switch to your lower gauge.

Install the switch near your lower helm fuel gauge.

Hope this helps,

Kevin

Kevin,

Wow…the world’s greatest site for boat wiring ever…thank you for your contribution to the boating world!!!!

Here we go…2002 Harbor Master 440W. Flip on the navigation lights at either helm, up or down, and within 10 seconds…pops the breaker and no nav lights.

I own a Multimeter…damn fine one at that…but have no idea how to use it, where to start or what to do to chase this down. Thought I would take the logical approach…hire the boatyard to fix…but they have had the work order now for 7 months and have just not had a chance to get to it.

I know I can chase this problem down with your professional guidance.

Help.

Warmest Regards…

Walt

Hi Walt,

First:

• Test the breaker.
• Check the rating on the breaker.
• Remove one of the wires from the breaker.
• Connect one of your meter wires to the open breaker tab and the other to the wire.
• Select AMPS on your meter.
• Turn on the switch.

If the current that trips the breaker is less than the breaker rating, replace the breaker.

Second:

• Reconnect the breaker.
• Most individual navigation lights draw less than 1 amp. Remove one of the nav light wires from either nav light switch (gray/green for nav lights and gray/blue for anchor lights). Connect your meter using the same method used above.
• Turn on the switch. Do this for each output wire on each switch. This will determine which wire has the short.

Once your determine which wire is causing the breaker to trip, follow the wire to the light it is associated with. The problem will be between the switch and the light.

You should be able to determine which wire is causing the problem in a few minutes. Finding the short may take a while, but it will be a simple fix.

Let me know if you have any questions,

Kevin