Carver Owners Forum

So, following up a bit on this...

I have a friend with a "240" boat, but his has an isolation transformer. In the wiring for the boat, they actually do not connect to the neutral on the 120/240 50A shore connector, so there actually is no 120VAC going into the boat. The two hot leads for the 240VAC go right into the transformer and on the output of the transformer it is center-tapped, which allows you to feed 120VAC circuits as well as the 240VAC circuits. This is the reason why the 120-240VAC adapter would not work on his boat.

However, if you don't have an isolation transformer, then the neutral should be connected in the shore cable, and the adapter should work. I'm curious if the folks that are having issues know if they have an isolation transformer or not on their boat.

A little more complicated than one thinks it is. Power comes in on a single cord @ 240 volts. 2 hot 120v leads. a neutral and a a ground. It then splits into 2 separate 120 volt panels which makes it sound rather simple as if I feed only a single 120v line why then cannot I simply power one side of the panel to get some needed power on board?

Carver uses an isolation transformer where the 240 volts is introduced and this transformer splits it into dual 120v lines which are now isolated. This is the best and safest way to avoid galvanic corrosion from happening.

I have one of these on board, probably weighs 250lbs or more. This is factory from Carver by the way. Not an easy task to bypass and supply power to one side plus the galvanic corrosion protection would not exist any more. https://www.pysystems.ca/resources/arti ... ansformer/

Why an isolation transformer? https://www.pysystems.ca/resources/boat ... -isolator/

km1125 wrote:So, following up a bit on this... I'm curious if the folks that are having issues know if they have an isolation transformer or not on their boat.

I have an Isolation Transformer on my boat and I require 240V for anything to work.

My friend has a 46 Cruiser and he does NOT have an Isolation Transformer and he also needs 240V coming into his boat for anything to work as well.

Not sure what all this means or if it results from the Isolation Transformer, however, it is not a real issue for me as I have a way around it. It is just the way it is.

It would be nice to be able to plug in while I am on the hard to charge my batteries for convenience, however, I just use a battery charger.

As for the fridge, it runs off my batteries, but normally don't need the refrigerator while on land. My house battery is charged while on land with my solar panels.

Greg

Problem is it would be nice to charge the batteries while on the hard in times when one has work to do on board and require a little lighting and maybe listen to some tunes while working. Also a good idea to top all the batteries up before leaving her for winter not to mention topping things up before launch come spring. I ended up installing a NOCO 4 bank charger permanently connected to all 4 banks with a 120v inlet by my shore power where I can plug in a standard 120v cord for supplying the power to the NOCO unit only. I only use this temporarily on the hard by the way.

Capable of independent battery type outputs which is ideal for my incoming Lithium house bank mixed with standard wet cells.

Charger........https://no.co/genpro10x4
120V Inlet....https://no.co/gcp1e

Tireless wrote:Qr Bbpost
My friend has a 46 Cruiser and he does NOT have an Isolation Transformer and he also needs 240V coming into his boat for anything to work as well.

Yea, I'd definitely like to know more about that one. I'll see if I can track down some wiring diagrams for it. Should not be an issue for his boat.

km1125 wrote:Qr Bbpost

Tireless wrote:Qr Bbpost
My friend has a 46 Cruiser and he does NOT have an Isolation Transformer and he also needs 240V coming into his boat for anything to work as well.

Yea, I'd definitely like to know more about that one. I'll see if I can track down some wiring diagrams for it. Should not be an issue for his boat.

I spoke with my friend and he confirmed what I said to be true. He requires 240V into his boat for anything to work. He does NOT have an Isolation Transformer.

He is of the understanding that the 240V coming into his boat is split at the panel into two separate 120V circuits for use in the boat, much like your home.

I dont think the Isolation Transformer is the answer to the issue and I am of the view it only ensures that the boat is protected from dirty power, surges and polarity issues. Not all Carvers come with the Isolation Transformers and it was an option at the time of purchase. I know that there are Carvers out there that don't have Isolation Transformers that require 240V to run anything.

I am not sure why that is, and I wish it wasn’t the case for convenience sake.

km1125, if your able to figure it out let me know. My friend is going to look at his wiring diagram and to see if he can figure it out. The conversation has sparked his curiosity as well.

Greg

With no isolation transformer the it should be rather easy to introduce 120v to one side of the panel via an adapter plug of some sort. Assuming you already have a dual 30 amp adapter, using only one of of the 30a should introduce 120v on one of the panels. If one just wanted to run the charger then this would more than suffice. If only 120v 15a is available then another adapter on the 30a side will work as well however one would be limited to the 15a circuit. The above is what I tried when I got Midnight Sun and she was on the hard only to find out there was an isolation transformer which must have 240v in oder to split into dual 120v panels.

A regular existing 120V 15A outlet inside the boat or cockpit can also be an inlet to power up one side of the panel from a 120V source. Shut the mains at the panel off so you don't back-feed the transformer but any circuits on the load side of the main for that outlet that are turned on would power up. You'd be limited to 15A but it's an easy way to get power into the boat if all you have is a 120V source. Swap the female end of an extension cord to another male end to go into one of your outlets. Use a good 12 AWG cord.

Viper wrote:Qr Bbpost A regular existing 120V 15A outlet inside the boat or cockpit can also be an inlet to power up one side of the panel from a 120V source. Shut the mains at the panel off so you don't back-feed the transformer but any circuits on the load side of the main for that outlet that are turned on would power up. You'd be limited to 15A but it's an easy way to get power into the boat if all you have is a 120V source. Swap the female end of an extension cord to another male end to go into one of your outlets. Use a good 12 AWG cord.

Hmmm, something I have done many a time at home to power up using a generator in desperate times. Backfeed! Never thought of this for the boat though, thanks for the tip.

Viper wrote:Qr Bbpost A regular existing 120V 15A outlet inside the boat or cockpit can also be an inlet to power up one side of the panel from a 120V source. Shut the mains at the panel off so you don't back-feed the transformer but any circuits on the load side of the main for that outlet that are turned on would power up. You'd be limited to 15A but it's an easy way to get power into the boat if all you have is a 120V source. Swap the female end of an extension cord to another male end to go into one of your outlets. Use a good 12 AWG cord.

On a lot of GFCI-protected outlets, that won't work. You'll trip the GFCI. There might be some GFCI's that will tolerate it, but I haven't run across one yet.