step up transformer to run air con

[greensail]

I have worked on many ships operating 50hz fridges, washing machines, aircon etc on 60hz. It works fine. Washing machine cycles are quicker. I would suggest though, the life expectancy is shorter.

If the Air Con units are already fitted, I would buy a transformer and use them until they die. A stepup transformer are not overly expensive or heavy. Definitely much cheaper than changing the Aircon units or buying a large inverter to change the frequency.

[smac999]

Originally Posted by Adelie

The OP did not mention Hertz in any post here and they are in Hawai’i which runs US standard so I don’t understand how there started being a discussion of a frequency mismatch.



Is there a post in another thread where the OP indicates European boat using 50Hz?

Op said 230v. Which implies 50hz. 120/ 240 would be 60hz

[redneckrob]

Originally Posted by smac999

Op said 230v. Which implies 50hz. 120/ 240 would be 60hz

Exactly.

Additionally, I was specifically referring to the advice to "If you do use the step up transformer you’ll a 230c inverters that can synchronize with shore power and provide the amperage boost needed to avoid popping breakers." This is spectacularly poor advice.
a. The OP stated he would be using U.S. mains 120v, which is 60hz.
b. As far as I know (again absent some crazy Korean inverter since they use 230V at 60hz), all 230v inverters are 50hz because they are designed for and used in the rest of the world that uses 230v/50hz mains.
c. If one steps-up 120v, 60hz AC to 230V it will still be 60hz.
d. If one tries to synchronize a 230V, 50hz inverter from item b. above with the 230V, 60hz stepped up power from item c. above to "boost" power one will not get the results one seeks and will almost certainly get detrimental results one does not seek.

The fact that neither the OP or @Adelie mention hz in no way mitigates the bad things that will happen to either of them or anyone else if they fail to take hz into account! TLDR, don't under any circumstance try to use a 230V/50hz inverter to "boost" 230V/60hz power!

[Jammer]

Most larger yacht marine A/C sold in the USA and most of the Americas is 230v 50/60 hz. Most smaller marine A/C sold in the USA and most of the Americas is also 50/60 hz and is either 120v or can be field converted between 120v and 240v. Check defender.com or Fisheries Supply and you can see for yourself.



I've run 27,000 btu on 30 amp 120v service (barely). I wouldn't necessarily recommend that. 24,000 would be workable in the absence of other loads.


Finally I will point out that many things that are technically possible are not necessarily good life choices.

[Jweyndling]

With regard to the issue of 50Hz v 60Hz, some AC units are designed to run on either and should be clearly marked as such. I recently called Dometic on this issue. My 230 V AC units are marked for 50Hz only. Dometic said that they will run OK on 60 Hz but you will probably shorten the life of the compressors. As I only use the units occasionally, that does not bother me too much.

If you are starting from scratch, the way to go is the Mabru 12V units. Super efficient and will run all night from lithium battery.

[Nicholson58]

Most dock and marina power is provided to the pedestal by 220. The legs are split to two 115 volt circuits. These are anti phase since they came from a 220 main. You can confirm this with a volt meter at the pedestal outlets. Use a combiner to put the two 30 amp circuits back into one 50 amp 220. Hubble makes the combiner as a Y junction. They also make a souped up version with a brain box in the junction that prevents making a mess of a badly wired shore pedestal.

[svkatface]

Unless you are planning a trip to europe you should seriously consider a 120v ac unit. I bought a small one from Flagship marine and it has worked well for many years. If you only plan on using it at the dock then a residential unit in the companion way or hatch works wonders. I used a Sears unit in Maryland summers. It was about 200 dollars. I could run my small Flagship A/C off an isolation transformer in Europe. It was OK at 50 hz. But it is not as big as your unit. Cost for a replacement A/C is not going to be too different from that of all the new kit to deal with the voltage. Transformers are heavy, fairly large, and can get hot as well so consider carefully the hidden costs of installation and loss of space.

[wingssail]

Originally Posted by Jweyndling

With regard to the issue of 50Hz v 60Hz, some AC units are designed to run on either and should be clearly marked as such. I recently called Dometic on this issue. My 230 V AC units are marked for 50Hz only. Dometic said that they will run OK on 60 Hz but you will probably shorten the life of the compressors. As I only use the units occasionally, that does not bother me too much.

If you are starting from scratch, the way to go is the Mabru 12V units. Super efficient and will run all night from lithium battery.

Mabru units cost $USD5000, plus installation.

The Mabru uses 22-28 amps which is around 300 watts, quite low, but it is only 7000BTU. 7000BTU is enough for only a small cabin. In an 8 hour night it will use 2400Wh, quite a big lithium battery will be required to supply that, and recharging it every day will be a pain. The cost of the unit, plus the Lithium batteries and associated equipment and infrastructure, plus enough solar to recharge it, will add up to quite a lot of money.

Considering that my 8000TBU units has a max power usage of 700watts, (much less in energy saving mode) and costs $323 with zero installation costs it was really not worth considering the Mabru for me. I won't try to run it on batteries.

[DeValency]

These are available but most probably the a/c runs on 50Hz and the 115V shore power typically go with 60Hz. This may either damage the compressor or significantly effect the efficiency.

[OS2Dude]

What is your current inlet? Are you at your current marina for the foreseeable future? 220 is just two opposing phases of 110. If your marina's power pedestals have two outlets, it is possible (probable) that together they would be 220. They make a combiner that will combine two opposite phase 110 outlets into a single 220 cable. The only potential drawback is if the pedestal is 30 amps, even combined to 220 it will still be 30 amps.

[GrowleyMonster]

Originally Posted by captianjuan

Any recommendations for a transformer to run the AC onboard. I just purchased a boat and the air con is set up for 230. Dock only has 120 available (U.S.). I intend on keeping the AC or buying another with equal capacity (seems to be all 240 after 16k BTU) so not looking for musings on sailing without AC and the joys of the wind blowing through the cabin. Ive been there plenty. I see Victron makes a transformer. Im also converting to Lithium and contemplating buying two Victron inverters, one for 240 dedicated to my high usage systems and another for 120. any thoughts on that?
thanks in advance,
fair seas

If you are talking about a window unit then the proper transformer will cost more than a 120V A/C unit.

My Charles isolation transformer can be wired to provide either 120 or 240V output from either 120 or 240V input, 50Hz or 60Hz. Connected for 240V output, it can still provide 120V from Neutral tap to either hot leg. However it is pretty heavy and it wasn't cheap. And of course the obvious... 60Hz in, 60Hz out. 50Hz in, 50Hz out. Some appliances don't do well when connected to the wrong frequency. Some transformers can't handle full rated load at lower than spec frequency so a transformer that will or might be used for 50Hz must be rated for 50Hz.

The separate inverter setup would work but wow you are gonna want a serious big bank for that, even if you don't mind running the generator a lot. An inverter with the correct frequency for your A/C would solve the frequency issue if there is one, of course.

Have you ran the A/C from shore power? If you have the capability of doing that, I suggest you check the startup current and operating current draw of the unit, and crunch the numbers before you decide on what to do. If you can get a professional electrician, better yet a marine electrician, to go over the figures with you, so much the better.

The higher voltage is more efficient. Lower copper losses due to lower current required to get the same work done, or else smaller wire permissible, again, due to drawing half as much current. Still I suspect switching to a 120VAC unit or maybe swapping out the motors would be your best move unless you have a pretty big boat with a lot of space to cool. Oh but I see you only have 120V available at the dock. Wow, that's kinda strange. At my marina some slips only have 120V but there are plenty of slips with 240V connection, too. You really need to run the unit from shore power and check the load, You can't just go by nameplate data on the unit.

Whether you use a transformer or inverter, plan ahead for the cooling required for your conversion equipment. Either one will generate significant heat, and without adequate ventilation you could have a meltdown. Electrical fires are easily extinguished if caught in time, but the lingering smell will take a long, long time to eliminate.

Unless you are very familiar with electricity I would not DIY this without some oversight from a pro. This isn't like adding cabin lights or hooking up a VHF.