110V AC in a 220V AC World!

[Redline4Life]

I am presently in New Zealand with my Newport 41. Of course, our boat is rigged with 110 AC but we want to plug into shore power. I am just here for a short while so I will not be permanently switching to 220. I understand all I need is a step down transformer is that correct? Our battery charger is 20 amps at 110v. The microwave which we rarely use draws 10 amps at 110v. We have never blown our 30amp 110v breaker so would a 15 amp 220v transformer work? We plan to run a heater off the ac too but don't have one yet. This is all a bit confusing to me so I appreciate the help. Thanks a lot.

R4L

[pschoonveld]

The larger dilemma is the hertz of the mains power. US is 60 hz and NZ is 50 hz. To change between the two requires more than voltage step down. It's more like a power conditioner than a simple AC->DC converter.

Devices to switch between cycles are large, heavy and expensive. If you have direct AC-powered gear (unlike DC gear such as laptops, etc.), the cost of compatibility likely rivals replacement.

To help:
Mains electricity by country - Wikipedia, the free encyclopedia

[Redline4Life]

All I really need is to be able to plug in to shore power to keep batteries charged so I don't need to run the engine once a week. Oh, and I'd like to plug in a heater because it's getting cold down here.

R4L

[rbarkas]

Originally Posted by Redline4Life

All I really need is to be able to plug in to shore power to keep batteries charged so I don't need to run the engine once a week. Oh, and I'd like to plug in a heater because it's getting cold down here.

R4L

pschoonveld is right - a 220v 50hz electric heater, portable battery charger and a good quality power lead will cost a lot less than a decent converter and your 110vac electrical equipment won't be at risk. Don't connect the boat system, just use the extension lead(s) - just make sure you get leads that are rated for the load they will carry.

[Stu Jackson]

I just returned from a land trip in New Zealand. The wimpy little converters we bought in the States were too small for even charging my laptop! We ended up at Dick Smith's, the New Zealand version of Fry's Electronics, and bought a converter. For the 65 watt (65 volt amps) required for my laptop's brick, the converter was a honking big monster, weighs a ton. It's Model M1163, 110V, 150 VA. They make one larger one, the Model M1164, good for 250-300 VA (watts). Do the math on volt amps and you'll find the model I bought was only good for 1.3 amps (on the 110V AC side)! You'll likely NOT be able to find a converter at Dick Smith's that'll work for you. And if you do, you'll find it incredibly HUGE!!!

They do convert 50/60 Hz, so that's not an issue and wasn't for me - my laptop brick took both, your charger may not be able to.

You'll need to go to a marine chandlery and/or talk to dockmates to figure out how to do that. You're likely not to be the first American who's had that issue.

Your most likely best bet is to invest your money in solar panels, rather than a short term use converter, unless there's someone near you who has the same problem and wants to "pass it along to the next guy."

[MarkofSeaLife]

Had the same probelm in reverse.

Needed to have a fan!

As explianed above buy a local power cable etension cord, small can battery charger, and a small heater

Costs much less


Can't fix your water heater though.

In hotter places solar panels are the go. I never have to plug in now!

[hellosailor]

Most heaters are resistance elements that don't care about Hertz, so a simple 220:110 stepdown transformer will make your heater work just fine. Those are also fairly cheap and if you've never blown your 110v-30A breaker, then yes, a 220v-15A transformer should be fine--but I'd look for 20A for a little extra safety margin there. And plug in the heater directly, or make Real Damn Sure that anything which might be insulted by the cycle change (like your charger) is totally off and secured first.

For the rest, I'd suggest as much 220V battery charger capacity as you can reasonably get, and then just use that to charge the batteries and run the rest off ship's power from them. There should be something available in a 'simple' charger that will do well enough if you're not going to be there forever.

[SVAuspicious]

I agree with hellosailor's first paragraph, but maybe not the second. Check your existing battery charger and see what it's input specs are. If you are lucky it is 50/60 Hz and a step-down transformer will do the job for you. If you're REALLY lucky the voltage range will be something like 95 - 250 VAC 50/60Hz and all you will need is connector adapters.

For heat, especially if you can run your existing battery charger, just run a construction-grade lead into the boat and a local heater.

Run your convenience outlets off an in-built inverter and you're set.

[LakeSuperiorGeezer]

Make sure your battery charger is a marine type, the type that isolates the DC from the AC ground; otherwise, you can have electrolysis that eats the metal on your boat. Do not use an automotive type battery charger. An isolation transformer also will prevent electrolysis and can be used with a automotive type charger. You have to see if the battery charger you have will work on 50 hertz so you can use an isolation transformer with it. Of course if the battery charger works on 50 Hertz and 230 volts and is marine grade, you do not need an isolation transformer. Also I agree that a local 230 volt heater and extension cord is a good idea so the isolation transformer can be much smaller. When you say the battery charger is 20 amps, is that on the 12 volt side or the 110 volt side because on the 12 volt side it will be almost 10 times smaller. If it says 110 volt 20 amp input that's a lot, then you need a 2.2 kVA (2200 watt) isolation transformer which is quite large. You may want to look at your actual 12 DC usage and buy a smaller isolation transformer or a smaller marine charger that works on 230 volts 50 Hertz. Are you just running a few 12 volt lights, or do you have like a 12 volt refrigerator and other high amperage 12 volt appliances. Need to make an estimate so you can size the charger or the isolation transformer.

[JimsCAL]

Note that most laptop power supplies today are 110/220V and 50/60Hz. No need for a step down transformer. Just check the specs on the brick. Ran mine fine with just a plug adapter when I was in Turkey last December.