220VAC or 110VAC

Hello everyone, I have a question that I hope is simple for those of you in the know to help with. First of all most of the time the boat will be in the U.S. The question is: If you could chose between Option 1- one 220VAC, 50A shore power cable feeding a 220VAC electrical panel for the heavy power users like air conditioners, water heaters, stoves, pumps, etc. and then split off a separate 110VAC panel for small appliances and outlets or Option 2- two 110VAC, 30A shore power cables feeding two 110VAC electrical panels where there would not be any 220VAC equipment installed, which would you chose?

The 50 foot fiberglass hull is stripped down with all of the wiring and equipment removed and trashed so everything will be a new install. The boat will have a full array of air conditioners, refrigerators, freezers, washer/dryer etc. The power requirements haven't been fully worked out but I know at lease 50 to 60 amps will be required. I think the single 220VAC, 50A shore power cable would be best but I don't know enough to make a wise decision. The boat will have a 12KW generator installed and I don't know if that will be a factor in making the choice or not. Also I don't know which option would be best for setting the boat up for use in Europe for periods of time.

Thanks for your help. Steve.

 

Two 110V panels give you the option of using shore power when 220V is not available.

 

Thanks Gonzo. That is a good consideration. Most places I've been have had 220 and 110 hookups but I certainly haven't been around enough to know how widely that is true. Another reason I was leaning towards the 220V 50A option is that I thought it might be easier to connect to the European power grids but again that might not be the case.

Thanks for the reply.

 

I would use the US style split phase panel, which supplies both 220V and 110V. Add a transformer (220V to 220V, both sides center tapped) and you can plug in anywhere (220V split, 110V single, 220V single) and still have everything work (ignoring 50Hz/60Hz issues). Plus the transformer solves grounding issues.

 

Thanks Jonr. That's what I was thinking too. Do you know of a good transformer brand/model I should consider?

 

If you plan on traveling, skip the 110volt circuit and 110 gear

When you are on the road you will hard pressed to find 32 amp 220 and will most likely be running off 16 amp 220.

An isolation transformer is mandatory for any substantial ac power system.

50 60 hz can be an issue. Choose your gear wisely.

Mastervolt makes good gear...http://www.mastervolt.com/marine/products/isolation-transformers/

soft start is valuable

 

You make a good point. I haven't too much luck finding dual frequency hvac, pumps, refrigerators, microwaves, washer/dryers, etc. I hate to have to run a bunch of inverters around for different equipment. This has to be a common problem for U.S. boats going to other countries for long periods so there must be a solution.

 

You need to choose either 60 Hz OR 50 Hz (with related voltages). Resistive loads can tolerate both frequencies but inductive loads (eg motors) will not be happy, and may fail.

I suggest picking the one where the boat is located most of the time, assuming that is where repairs/replacements (and additions) will also be done. You can of course use a frequency converter, which can have an isolation transformer built in, as part of your solution. That way shore power where ever you are can be used.

But think through your loads. You really don't want to be limiting yourself, or dependent on, docks with 50A outlets. Even 32 A 220V wont be always available.

I have a 50ft boat and am in the final stages of a refit. I have ditched both generators. I have over 1800W of solar panels, a 200A alternator on each engine and a large bank of Odyssey PC 1800 batteries that can take high charge rates. Put a 5000W inverter in if you anticipate a lot of simultaneous high loads, otherwise 3000W will be enough for washer or dryer,microwave etc. Consider hydraulic alternatives for some high loads - eg davit/crane, windlass, bow thruster.

I decided not to have air conditioning, otherwise I would have needed to keep one of the gennies. But I see no other reason to have one.

For refrigeration, I have 5 units on board including the icemaker. It is the only one that isn't 12v/110v dual voltage. The other 4 use less watts running on 12v than they do on 110V, because they use the Danfoss 12 v compressor and 110V has to be dropped to 12v anyway.

 

Pretty much anything that says "inverter" on it won't care about frequency - microwaves, refrigerators, heat pumps, washing machines.

 

When I look at your power requirements the first thing that comes to mind is a nuclear power plant, but it is rather difficult to get it licensed.

So the alternative is a system with two 5KW inverters, a battery bank and a switch mode charger. The charger doesn't care what's on the menu and even digests DC between 90 and 260 volts, the inverters generate your favorite 120V 60Hz so you can keep using standard US appliances.
I know Victron makes the equipment, Mastervolt probably does too. Quite expensive stuff, but freedom never comes cheap.
An additional advantage is complete isolation between shore power and the ship's circuit, without a heavy transformer.

 

The design as described mimics a Caribbean Mono-Hull Charter boat flagged US. USCG T-Boat.

No really inexpensive way to provide UK / US compatibility.

CDK has provided a popular approach. Although, I would add an isolation transformer to meet ABYC requirements.

That is, shore power wide input battery chargers essentially float power across a large battery pack using inverters to run AC loads at a specific frequency. By using an isolation transformer on the front end you can adapt to almost any shore power available within the limits of the available power. This then feeds the chargers.

The are advantages to this setup.

To name a few:

The inverters are selected for specific AC loads. Addressing each load AC surge and steady state current requirements.

Switching between charger power sources does not upset or interrupt operation of the AC loads.

Mark Cat

 

I've never bothered about ABYC, but if they really require an isolation transformer before a switch mode charger the book should be rewritten.
By design, all such circuits have a high frequency transformer separating primary and secondary, providing 5 KV isolation.

 

I'll add that a properly sized charger/battery bank/inverter setup can start and run loads (for awhile) that shore power can't. Ie, greater burst output.

My guess is that any of the newer appliances that use their own inverters don't care at all about the waveform shape either. So the less expensive, modified sinewave inverter should be fine to supply them.

 

CDK,

An isolation transformer is one way to meet the requirements. Not the only way.

You have to take a look at the overall install (and liability of designers and builders) for connection to shore power, safety, aging and wiring layout. Under this overall consideration, I would never rely on charger isolation over a transformer.

Before showing such disdain towards ABYC perhaps you should see what the standards have to offer. I use many different references for vessel design, ABYC, ABS, IEEE - 45, USGC T-Boat, 33 CFR 183, ISO, IEC, I find that all have at least something useful to say.

Perhaps you could help me understand the regulations in your area. Which standard is recommending a switching charger over a transformer for shore power isolation?

Thanks,

Mark Cat

 

If mostly staying in USA then I'd suggest have 110 VAC as primary. But you can also add some 220 VAC capability, and have outlets for both on board.

Attached is my AC schematic. In my case 230 VAC (50Hz) is normal, ie what the sole inverter delivers. But I can operate a range of legacy 110VAC gear because of the second transformer.

With 110 VAC shorepower I have battery charging and 110VAC / 60 Hz power from the 110 VAC panel and associated outlets.

With no shorepower, or 230 VAC shorepower, I still have 110VAC available as above BUT it is at 50 Hz. Resistive loads don't care. Inductive loads might age prematurely or fail, but those few remaining pieces of gear will be replaced once I leave North American waters.

Another part of my strategy was to have only LED lighting, and most of that is 12V. But some is AC and can tolerate anything from 90 to 270 volts. Then use as much 12V systems as possible. Refrigeration on board was dual 110V / 12V, and I noted that rated power consumption was lowest for 12V so the 110 VAC are no longer connected. They use Danfoss compressors, and the AC was transformed. My davit is now a 12V powered hydraulic unit, not a high amperage AC motor.
Brian