Adding generator auto transfer switch

[Wdeertz]

I recently added an auto start generator to my boat. My shore/generator switch is manual so if I lose shore power and the generator auto starts nothing is powered. I want to add an auto transfer switch and am looking for recommendations on brands/model. I’m a 50 amp boat. I need to also swap out my 2 position Shore/Generator manual switch with a 3 position switch (Shore/Generator/Auto). Appreciate any inputs on brands/models used. I have tentatively found this model for consideration 50A Transfer Switch.

 

[EngNate]

For the manual switch

Rotary Cam Switches

Rotary cam switches ranging in size from 20 to 2000 amps. UL listed and American-engineered.

controlswitches.com

 

[Sababa]

A different way of coming at this that I am planning to implement is to add a second Victron Quattro inverter, with each supplying one leg of the 50 amp split phase power to my panel. The generator gets wired directly to the inverters with the auto start triggered by the Cerbo GX when the house bank dips below 50%. This setup eliminates the transfer switch at the panel and delivers uninterrupted power if the shore power goes out, with the inverter automatically selecting the active power source and taking up the slack until the generator powers on. Or at least, that’s how it’s been explained and sold to me.

 

[SIBERNUT]

All you guys are diesel, right ?

 

[SteveK]

@Wdeertz
Are you saying the new generator came with auto start and you are looking for something to command the auto start and another device to auto switch from SHORE to GEN.

 

[more]

I recently added an auto start generator to my boat. My shore/generator switch is manual so if I lose shore power and the generator auto starts nothing is powered. I want to add an auto transfer switch and am looking for recommendations on brands/model. I’m a 50 amp boat. I need to also swap out my 2 position Shore/Generator manual switch with a 3 position switch (Shore/Generator/Auto). Appreciate any inputs on brands/models used. I have tentatively found this model for consideration 50A Transfer Switch.

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[Wdeertz]

@Wdeertz
Are you saying the new generator came with auto start and you are looking for something to command the auto start and another device to auto switch from SHORE to GEN.

Negative, the auto start is part of the inverter/battery monitor system. The generator will start based on voltage, SOC, temperature, depending on what is programmed. On my electric panel there is a manual switch to select either shore or generator power. If on shore power while at the dock the power is lost when the generator auto starts on whatever parameter is set the power doesn’t go to the panel since the manual switch is set to shore power. I’m looking to add an auto transfer so when power is sensed on the generator inputs it powers the panel. See attached schematic.

 

[Wdeertz]

A different way of coming at this that I am planning to implement is to add a second Victron Quattro inverter, with each supplying one leg of the 50 amp split phase power to my panel. The generator gets wired directly to the inverters with the auto start triggered by the Cerbo GX when the house bank dips below 50%. This setup eliminates the transfer switch at the panel and delivers uninterrupted power if the shore power goes out, with the inverter automatically selecting the active power source and taking up the slack until the generator powers on. Or at least, that’s how it’s been explained and sold to me.

Yes your approach is using the transfer switch built into the inverter to accomplish the transfer. I’m not interested in adding a second inverter at this time.

 

[Greg QS]

Watch out for those super cheap transfer switches. I have tried them for residential system. Failure rate is super high. They are over rated. Meaning they do not handle the load they specify and tend to burn up.

 

[Wdeertz]

Watch out for those super cheap transfer switches. I have tried them for residential system. Failure rate is super high. They are over rated. Meaning they do not handle the load they specify and tend to burn up.

Hence the purpose of my original post. The example I posted is generally used in RV’s. If there are any better quality transfer switches out there I am all ears.

 

[SteveK]

My magnasine inverter charger aso has that capability through the remote control and an added component.
Yes then you need to auto transfer theshore to GEN to avoid backfeeding the shore power.
After I looked at the possibility I then wondered when it would be used as in my case only if marina power was lost for more than 24 hours, which happened twice this year.
How about you?

 

[tiltrider1]

For quality I would look here.

VE Transfer Switch - Victron Energy

The VE Transfer Switch automatically switches between different power sources: between a generator and shore power, between an inverter and a generator or...

www.victronenergy.com

 

[Wdeertz]

My magnasine inverter charger aso has that capability through the remote control and an added component.
Yes then you need to auto transfer theshore to GEN to avoid backfeeding the shore power.
After I looked at the possibility I then wondered when it would be used as in my case only if marina power was lost for more than 24 hours, which happened twice this year.
How about you?

Yes that is exactly why you need the auto transfer switch for when shore power is lost. When at anchor you leave the switch in generator mode and if the auto start engages the loads get power.

 

[Wdeertz]

For quality I would look here.

VE Transfer Switch - Victron Energy

The VE Transfer Switch automatically switches between different power sources: between a generator and shore power, between an inverter and a generator or...

www.victronenergy.com

Thanks, wasn’t aware Victron made a transfer switch. This Victron switch is only usable for up to 40 amps which would probably work when used in auto mode. Thanks

 

[tiltrider1]

Then there is this one on Amazon.

Amazon.com

This one sounds to good to be true but I've been surprised by some of these Amazon deals in the past.

 

[luna]

You noted that you are a 50 Amp boat. At 52' long, I would expect that your electrical system accepts a 4 wire, 125/250 V split phase, 50 Amp service.

The Victron VE transfer switch is a 3 wire design and will not switch North America's 240 V split phase power. It's desIgned for the rest of the world's 230 V, single phase, 32 Amp service.

The North American RV industry has lots of options here.

Esco LPT50BRD LYGHT 50 Amp 120/240v Relay Base Transfer Switch

The ESCO 50A 120/240v Relay Base is an electrical transfer switch that automatically switches between multiple power sources, such as switching from shoreline power to generator power. This auto transfer switch is capable of handling a 50 amp power cord and up to a 12KW generator.

www.rvupgradestore.com

Other options exist on the same site and others.

One thing I would ensure is that the switch will actually switch back from the genset to the grid power once grid power is restored.

 

[Greg QS]

My choice would be victron. They have everything you need to make the system work. Stay all Victron makes it easier to get all the pieces to talk.
They have auto inverters, transfer switches, gen start equipment, and monitoring equipment . Its on my list to add auto start to the gensets for protecting battery levels when on the hook. Or in the event of a power failure and again low batteries.

 

[Sababa]

Victron does not appear to have a whole-panel auto transfer switch for US split phase 50A power. I think the dual inverter setup that I am installing is their recommended setup for that use case.