Easy Ac/Dc

Boat Wiring and Marine Electrical

Archive for the ‘Voltage Drop’ Category

Memory Loss

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Hello Kevin,

I have a Wellcraft Portofino that I have owned for several years.

When I bought the boat it had an AM/FM CD player in the cockpit that worked fine. I added a car style radio to the salon about three years ago. I wired the unit properly and attached the “memory” lead to an empty, fused position on the same 12 volt bus as the cockpit radio.

From day one the salon radio would lose it’s memory on engine start while the cockpit radio did not. In between engines starts is not a problem. I double checked my wiring, which seemed good and wrote the problem up to buying a cheap radio on sale.Sony marine radio

Midway through last season I replaced the cockpit AM/FM radio with a new Sony Marine unit. I now have the same problem with this radio! The tuner memory holds until I start engines. I just don’t get it!

The marine electrical is set up with two battery banks. The starboard bank is a 4-D and starts that engine and navigation equipment including the cockpit Sony radio. The port bank is a bank of four 6 volt deep cycle batteries wired series/parallel for 12 volts that start the port engine and also supplies the house.

I have checked all of the radio connections. I have switched the memory lead from the original fuse panel to different bus bars. Nothing has helped, as soon as I start an engine with the same battery bank the the AM/FM radio memory leads are attached to, the memories go blank.

I am starting to think that this is a surge problem. I believe I have confirmed this by using my master boat battery switches to start engines on the battery bank that does not have the radio memory. If I do that there is no memory loss. Starting and running my boat in this manner is not practical for me and leaves open the possibility of draining the wrong battery bank.

This situation is really starting to drive me nuts, I’d greatly appreciate any recommendations you may have.

Thank you,

Michael

Hi Mike,

Stereo memory circuits are sensitive to low voltage and you are suffering for a voltage drop “stack up” and will reset after only a few milliseconds of low voltage. This is very common with newer, higher draw, higher tech stereos.

The power feed to your helm has a drop. The more current that you draw through it, the more the voltage drop in the circuit. When higher draw devices such as bilge blowers, cockpit lights, stereos, the voltage drop is even higher. Slightly corroded connections induce voltage drops. When you start the engine, the source voltage (the battery) drops lower which makes the stereo input voltage that much lower.

Solution:

  • Increase the size of the power feed wiring and ground to your helm panel.
  • Run a dedicated power and ground lead from the battery to the stereo.
  • Make sure you use circuit protection at the source of power. An increase of 0.1 volts will mean the difference between the stereo memory resetting and remaining.

Hope this helps,

Kevin

Four Winns Wiring

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Hello Kevin,

I have a 1989 Four Winns Liberator 201 with a 350 OMC motor. I pulled the boat out of winterization today and wanted to check everything before I put the boat in the water.

When I went to hit the boat horn to test it, the horn sounded weak and eventually faded and did not work.

Next the navigation lights would not turn on. But when I hit the horn, the lights will turn on until the horn is released then they go off. Not sure if it could be a bad ground or short in the wiring.1989 Four Winns catalog for 201 Liberator

I removed the access cover and found someone has cut and spliced wires on the boat before. There are also some wires disconnected and zip tied up and others just cut.

The boat blower motor did work when starting the boat but now it also will not turn on. I’m not an expert in marine electrical by any means but would like to find the issue my self. I have a voltmeter but never used it other than checking glow plug relays on diesel engines. I have used a test light on trailers – checking for power and such so I do have a little knowledge but not where to start on this project.

Any help would be great.

Thanks

Mark

Hi Mark,

I’m a HUGE Liberator fan. I worked at Four Winns during the era after their production.

There are few marine wiring items to check since several things have quit working.

  • Main engine plug – round plug 1 1/4″ diameter on the starboard side of the engine. Unplug and check terminals
  • Boat harness ground – check ground connection on rear bell housing of the engine
  • Helm fuse block – check ground and power leads on the main fuse block under the helm

Once your find the corroded connection, replace as necessary.

Good luck,

Kevin

The Missing Fuse Mystery

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Kevin,

My boat is a 1990 Wellcraft Corsica 37′ Cruiser and I need help with the boat wiring.

The problem is that I have lost power in two circuits. I have checked all known fuses and can not find any blown. I have checked the breakers and none are tripped.

There must be another set of breakers or fuses I can not find. Is there anyone that might own a similar Wellcraft that might know if there is a hidden fuse or breaker box hidden somewhere on the boat? Wellcraft 37 Corsica

If it’s of any help, one of the circuits went to the factory installed radio.

Bill

Hi Bill,

Even though the fuses are good, they may have corroded wires or connections.

I would start with any connection that the two circuits have in common. For example, if they are powered by different breaker panels, but their grounds connect at the same point, check the ground. If they are powered at the same panel, check the feed wire to the breakers.

Wellcraft is currently owned by Rec Boat Holdings and they are built in Cadillac Michigan. They may have some information on your boat, but it is doubtful. I believe they are the third owner since your boat was originally built in Sarasota Florida.

We will also post your question and wait for a response for another reader,

Kevin