Dear Kevin,

I am currently beginning my first boat wiring project, a total rewire of a small Owens cruiser from the late ’60s.

Here’s my problem:

The old wiring runs behind the original paneling and headliner. I could try dismantling everything to remove and replace the wires, but am concerned about damaging any of the woodwork. It’s old. It’s gorgeous. It would be a bitch to replace.

I don’t mind leaving the old wiring in place and just running a new harness, but that still leaves the problem of installing the new wires without causing any damage.

Any ideas?

RP

Dear Ron,

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Kevin.

Hello,

If a European built boat comes to the United States, what is the best way to connect to shore power, i.e., 24/240V Euro to 12/120V American?

Thank you,

Warren

Warren,

If all of your AC appliances are designed for 50/60 Hz operation, then you can solve this with a Step UP transformer that will take the American 120v and up it to 240v.

You will need to research the AC components on your boat to answer this best.

The only connection between your 24v system and shore power is the battery charger. If your charger can handle 50/60 hz, then the Step UP transformer will work for this also.

Hope this helps,

Kevin

Hi Kevin,

I’m an airplane guy who’s redoing the boat wiring on my brother-in-law’s 1972 22’ Reinell.

I have a couple of questions.

We ordered a boat horn and a Smart Battery Switch from EzAcDc yesterday. However, we only ordered the VSR thinking it was all we need but after looking closer I’m not sure.

The boat has two batteries and a manual 1/both/2 switch. Should I change our order to the complete Smart Battery Switch System?

This boat has an original one-wire Delco alternator. I want the following but I’m not sure how to achieve it:

• The ability to disconnect the alternator from the battery when the alternator fails (if this is not important than I’ll forget about it)
• The ability to turn on a warning light when the alternator fails (we removed the original ammeter but the 3 in 1 gauge we installed does have a volt meter)

Do you have any suggestions i.e relays or any other components I can use to achieve the above results? I wouldn’t mind upgrading to a more modern alternator if that solves the problem.

Any direction you can give would be greatly appreciated.

Kevin

Hi Kevin,

A VSR works best when you have a dedicated engine battery and a dedicated house battery. The VSR makes the connection between the two systems.

A conventional battery selector (Off, 1, 2, Both) controls which battery the engine is connected to but does not control which battery the house is connected to.

The key to our partner’s complete Smart Battery Switch System is the dual pole On/Off battery switch. This acts like two on/off battery switches combined into one body.

• When the switch is Off, only emergency devices are connected to the house battery.
• When the switch is On, the engine is connected to the engine battery and the house is connected to the house battery.
• When the engine is running, the alternator first charges the engine battery. When the engine battery hits 13.7 volts, the VSR connects the engine battery and house battery together and begins charging the house battery.
• When the engine is off, the VSR keeps the batteries connected until the battery voltage hits 12.6 volts. When it drops below 12.6 volts, the VSR breaks the connection and allows for enough reserve in the engine battery to start again.

I would not worry too much about a way of disconnecting the alternator if it fails.

In the event of an alternator failure, your system voltage would begin to drop. With the complete VSR system, once 12.6 volts is reached, the VSR will open the connection between the engine and house batteries. Your engine will continue to run until the battery voltage is below 10 volts. When the engine dies due to low voltage, you can turn the battery switch to the COMBINE position. This will manually parallel the batteries and allow you to start your engine and continue running until your battery voltage is to low to run the ignition system.

You will probably run out of gas before you completely drain two batteries running only a simple ignition system on a single stern drive.

Thanks

Kevin

Hi,

I was given your email address by a friend who highly reccomended you.

I’m just about to rewire my boat as it’s winter. There are a few things that I would like to know before I start.

What would you suggest as to the thickness of cable from the battery to the 6 gang switch panel? I’m only running the normal things:

• Fishfinder
• VHF radio
• CD player
• Bilge pump
• Lights
• Horn.

I am also wondering if I should put an inline fuse in the live cable between the battery and switch panel and what size fuse?

Any other advice you could give me on boat wiring would be much appreciated.

Many thanks for your help

Paul

Hi Paul,

I am posting a handy spreadsheet that will help you calculate all of your boat wiring sizes.

Once you fill in the blue boxes for total wire length, the sheet will calculate the correct wire size needed for each wire run and for your main panel feed.

You will want to put a fuse or circuit breaker as close as possible to the battery. The size of this will be dictated by the total draw of your panel (Cell C20)

Emergency devices (nav lights, horn, VHF radio, bilge pumps, and blower) are typically wired for 3% voltage drop.

All other devices are usually 10%. Some stereos cannot tolerate 10% and you will need to run them at 3%.

Please let me know if you have any questions,

Kevin