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.

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

Hello Kevin,

My question is regarding marine wiring.

On my marine electrical, I’m using an isolation transformer in order to transform 220V to 110V.

Recently, the boat’s reverse polarity indication light is on. I’ve opened the circuit to see how this indication is measured and saw that there is a diode and led connected between the neutral and the ground.

I’ve realized that in the current situation the output of the transformer is basically floating, therefore the neutral line can have any voltage. One of the solution that I’ve seen online is connecting the neutral line at the output of the transformer to the boat’s ground (that is not connected to the shore’s ground). So I have several questions about it:

1. Is there advantage in connecting the neutral to the boat’s ground over working with floating voltage?
2. Is it ok to make this connection?
3. For about a year, the indication was off, what can be the cause for it to be on now?

Thanks in advance,

Ilia

Hi Ilia,

At the source of power, the neutral must be connected to the ground. With an isolation transformer, this is on the output (boat size). Please connect the output neutral and ground together immediately. It is an extreme shock hazzard as is.

The reverse polarity indicator is connected to the input side of your transformer. With an isolator transformer, the light is more of a nuisance than a concern. It is telling you that the polarity is reversed (Neutral is hot) on the input. Since you have an isolation transformer, you really don’t care as long as the neutral and ground are connected together on the output side.

Hope this helps,

Kevin

Hi Kevin,

I have a 1978 30′ Tollycraft sedan. My question is in regards to bonding.

My boat has a fiberglass hull, twin gas motors, two stainless steel fuel tanks, twin direct shaft drive, twin rudders, battery charger, isolator, four batteries with two boat battery switches, electronics (VHF, GPS, Fish/Depthfinder), 120 volt fridge, 120 volt water heater, 12 volt lighting.

When working on the boat, I noticed a lot of the marine wiring that appears to be old bonding wires is old and has either bad connections or has completely broken away from the parts it was connected to.

The boat was recently hauled out and new zincs and a new grounding plate were installed. What is the best method for bonding (wire size, methods for attaching, one main bond wire that others are connected to, or each individually bonded, etc.)?

I’ve seen various articles on bonding but remain not completely clear on the correct way to bond the boat and make sure all grounding has been done correctly.

Please explain.

Thanks,

Chuck

Hi Craig,

Here are the current ABYC standards for marine electrical systems. Please check out Page 31 and 32 which spell out how to bond your system.

Once you’ve checked the specs, please let me if you have any other questions.

Kevin