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

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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

Hello,

I would like to add a smart battery switch system with VSR, but am not sure how to do it.

On my 2008 Yamaha F150TXR, there is a second battery plug under the engine cover. This is illustrated in the owner’s manual along with a wiring diagram for adding a second battery with optional part available from Yamaha.

I contacted Yamaha customer service and was told that the part’s suggested retail is around $70. I asked what it consisted of and the agent pulled the part and informed me that it is a piece of 10 AWG wire with a bare end and terminal to connect to the mating plug under the engine cover and a battery connector on the other end.

They further informed me the Yamaha’s regulator/rectifier actually splits the ac from the stator to achieve isolation. In effect, I have two charging systems with a common stator/rotor assy. Both batteries will charge when running and will be isolated from each other when the engine is turned off! It sounds like a wonderful innovation and a real no hassle rig to me.

Can you tell me if I even need a VSR? If so, how would I go about adding the smart battery switch kit from EzAcDc?

Kind regards,

Bryan

Bryan,

If I had a F150TXR, I would take full advantage of the dual output alternator. Most engines do not have this and then a VSR is the best alternative.

I would make sure you have circuit protection at the battery end of your 10 AWG wire.

Great question,

Kevin

Hi Kevin,

I’m about to add a second battery to my 23’ center console. My current set up is a starting battery with all the electronics panels tied into it. I want to add a second battery (deep cycle) for all of my electronics, leaving the starting battery solely for the engine.

I’ve read a lot about VSR or automatic switches vs manual switches and would like to go with an automatic setup. I’ve actually been to two marine mechanics so far, and neither has ever seen this automatic type of switch before. So I’m trying to gather some basic info in layman’s terms so that I can help them through it.

But, I’m having trouble visualizing what the setup will look like. I’ve basically got to move all my electronics over to the new deep cycle. I’ve seen many wiring diagrams using a VSR switch and most of them have isolators too. How are the isolators involved? I thought the VSR did everything.

Thanks,

John

John,

You definitely do not need an isolator when you are using a VSR. A VSR combines the benefits of a battery isolator and battery switch into one automatic box.

The logic behind the VSR is very simple. When one battery goes above 13.7 volts (the engine is charging the battery), the VSR completes the connection between the two batteries and allows the engine to charge both batteries. When the system goes below 12.8 volts (the engine is no longer charging the batteries), the VSR opens the connection between the two batteries and leaves reserve cranking power in the starting battery.

Here is a great graphical representation of the VSR system from EzAcDc.

Basic System

• Both batteries have a common ground - My preference is to have all grounds connected to a ground block and only 1 wire to each battery ground connected with lock nuts (not wing nuts)
• Engine positive battery cable connects to positive of battery 1
• All electronics connect to positive of battery 2 – My preference is to connect these to a power buss with in-line circuit protection as close as possible to the battery positive connection

VSR Cable Connections – all at least 8 AWG wire

• Short 8 AWG red lead (7″ or less if possible) from battery 1 positive to in-line circuit protection (70 to 100 amp)
• 8 AWG red lead from circuit protection to VSR
• 8 AWG red lead from VSR to battery 2 circuit protection
• Short 8 AWG red lead (7″ or less if possible) from circuit protection to battery 2 positive
• VSR ground reference – 16 AWG black – connect to ground buss

Hope this helps.

Let me know if you have any more questions,

Kevin

Thanks for your quick response Kevin!

I thought the same thing – that the VSR performed the function of the isolator. The wiring diagram from BEP shows three isolators or switches.

They also make a product that clusters these isolators/switches with the VSR.

Is the only purpose for these additional switches so that I would have the ability to completely shut down each of the batteries and override the VSR to manually connect the two batteries for emergency starting?

Thanks again for the basic system set-up you outlined as well!

-John

John,

BEP makes some great battery switch clusters.

Your understanding is correct on the additional switches. They allow you to completely shut down the system and perform an emergency, manual parallel if desired.

Hope this helps,

Kevin