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Old 21-04-2011, 20:18   #16
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Re: Isolation Transformer Victron vs Mastervolt vs Charles

I have the Victron 7000W isolation transformer and can confirm like jedi that it is very quiet even when fully loaded.

One thing to consider is that it does put out a lot of heat, so install with very good ventilation.
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Old 15-08-2011, 19:29   #17
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Re: Isolation Transformer Victron vs Mastervolt vs Charles

We finally got the Victron 3600 installed last week. The unit is quiet and so far hasn't put off much heat. We have air on the boat, so I know there are good amps pulling down. no issues with start up and I am getting a 4 - 6 volt boost. When my air is running, the power used to pull down to 109 volts, Now the with the air running, the voltage is around 114.
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Old 17-08-2011, 11:59   #18
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Re: Isolation Transformer Victron vs Mastervolt vs Charles

I have a basic quesion about isolation transformers: If they convert 220v to 110v, but don't convert from 50hz to 60hz, what effect will this have on my electrical system?
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Old 17-08-2011, 12:16   #19
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Re: Isolation Transformer Victron vs Mastervolt vs Charles

That depends very much on the system. Most systems can handle the different frequency. It's mostly for systems that utilize synchronous motors that will give you problems as these motors have a speed that is related to the frequency. Not many of those on your average boat I'd say. You can have a look at the specific systems to see what the input specifications are. Things like boilers, light bulbs, coffee machines are perfectly capable running on the alternate frequency.
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Old 18-08-2011, 18:39   #20
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Re: Isolation Transformer: Victron vs Mastervolt vs Charles

I have been continuing to research / work this trade off. So far, here is the information I have found:

I need about 30A at 230V to carry all of my needs, still working around the issue that US docks are either 120, 208, or 240V. 50A at 120 stepped up might be enough especially if I have an inverter which can carry some of the peak load for a short while and/or offload the chargers and hot water heater when the loads are high.

Charles Marine: HEAVY and Noisy, I don't have room and don't want to be installing a 230lb item. Don't have a good place to put it which can handle the heat.

Victron Energy:
3600 watt toroidal transformers: would need two of these. Victron says these CANNOT be paralleled even at reduced load. I was considering two of them pulling a combined 50A @ 120V for 25A @ 230V which would be well under the rating for the units (i.e. 3000 watts max per unit). By stepping up 120 this completely avoids the 208v vs 240v dock power issues which seemed attractive. Additionally, if in a 230V region could rewire for 1:1 and continue to have isolation. I even looked at putting them into parallel victron inverters and then combining after that point but could not get victron to "support" that configuration either. Unfortunately, while I have two busses one of them can pull more than 3600 watts by itself.
7000 watt toroidal transformers: Looked like a good solution, however, cannot step up 120V power and will not let ANY power through below about 205V (the soft start circuit and fans will not activate) so on a 208V dock power a bit of loss on the dock and it would go away. Also can't use this unit in front of a wide voltage power acceptance battery charger as the transformer is more limited than the charger...

Mastervolt:
Mass GI 3.6kw: Nice unit, based upon converting to high frequency then using an isolation transformer at high frequency and then converting back. Some have suggested that there is no transformer thus only silicon as an isolation. This does not appear to be the case, there is a "winding and core" isolation just much smaller as higher frequency needs a smaller transformer. Will only do 1:1 voltage but will accept 90V - 260V and output the same so can be used before a wide voltage battery charger. Can be paralleled for more power (up to 4 of them!)
Mass GI 7KW: same as above but twice as much amperage. This would get me 32A at 208V - 240V and when hooked up to 120V would pass through 32A also so could run a wide voltage battery charger.

Mass GI Multitap 7KW: This unit is described in the manual for the previous two units. However, while in the books for a couple of years I have not managed to determine if/when the unit will surface. The manual claims it can absorb 90V - 260V and output 230V +/- 5%! It appears the input / output would each be limited to 32A maximum so if running on 100V input it would be able to produce 3200Watts, if the input is higher than 230V it would be limited to 32A output and somewhat less on the input. Two units can be paralleled for up to 64A of power! Two years ago I thought this one was right around the corner and have been holding out for it. Unfortunately I think this one may not make it out of the design room...

A possibility is to have the capability to switch in a "boost" transformer to kick up the 208 to 230 and perhaps an autotransformer to boost 120 -> 230 prior to the isolation transformer (this would allow up to 64A of 120V power to be boosted to 32A of 230V power). However, all of these have the risk of plugging into the wrong power and letting the smoke out of the electronics! I reallly like the concept of the integrated device but don't know how much longer I can hold out.
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Old 19-08-2011, 02:16   #21
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Botany Bay,

How did you get to that 30A @ 230V requirement? Did you take the sum of every AC powered device you have aboard? We do fine with half your requirement....

Ciao
Nick.
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Old 19-08-2011, 09:29   #22
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Re: Isolation Transformer: Victron vs Mastervolt vs Charles

As a long term live aboard I prefer to not run power systems heavily loaded compared to their specification (seen too many live aboard boat fires in the last 20+ years), however, this is the list of equipement which automatically cycles and can all be active at the same time:

Fridge: 7A @ 230V
Air Conditioner 1 in reverse cycle heat mode: 10A @ 230V
Air Conditioner 2 in reverse cycle heat mode: 10A @ 230V
Washer / Dryer: 8A @ 230V
Hot Water Heater: 7A @ 230V
Battery Charger (30A @ 24V) -> 7A @ 230V

Other loads:
Microwave: 4A @ 230V
Misc Electronics: 3A @ 230V

So the total for the "automatic cycling" equipment is 7+10+10+8+7+7 or 49A @ 230V, running on a 208 circuit would be 54A. This does not include the 7A - 10A of "controlled loads" nor does it include creature comforts like a blow dryer (ok, soI have no hair but friends do) so the total could easily be 60A if you turned "everything" on.

Now, you are correct it is unlikely that everything will cycle on at the same time, however, a likely configuration in the winter is both heat pumps running because the boat is cold (ok so I live in So Cal now but my blood has gotten thin also), turning on the washing machine and because that is pulling hot water the hot water heater kicks in. That alone is 35A of load at 230V.

Now if using a inverter/charger it can be programmed to limit the charger function when large loads are being pulled so I don't count that and it could add to the AC for the short term larger loads.

So, it just depends on how you use the boat. I am looking for a bulletproof live aboard where I don't have to run around telling friends "don't turn this on at the same time as that or you will trip a breaker". This tends to make people fearful and not want to touch anything. Probably the difference is having lived aboard for over 20 years I find that trying to make sure manually that systems are not overloaded by not turning something on will eventually result in a higher than desired failure rate, just do it right the first time.

I am definitely not saying that my solution is good for everyone, just the design point I am trying to achieve.

Thanks for the input, I really appreciate people poking at the basic assumptions to make sure I am not missing anything.
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Old 19-08-2011, 15:35   #23
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How can your fridge pull 7A at 230V? Mine only at maximum pulls 5% of that; 7A at 12V and most of the time not half of that.

Also, you can switch the water heater so count it as a controlled load. My 18kBTU air conditioner pulls 7A at 240V... how big are your two units? You always need to run the two of them? You must be running 40-50 kBTU at that 4.6 kW draw!

The battery charger is also a controlled load like you write. I must admit that I don't know how big your boat is but I always thought that we used a lot of power on our 64' boat with all the gadgets and A/C and washer/drier etc. but you more than double it :-)

ciao!
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Old 19-08-2011, 17:14   #24
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Re: Isolation Transformer: Victron vs Mastervolt vs Charles

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Originally Posted by s/v Jedi View Post
How can your fridge pull 7A at 230V? Mine only at maximum pulls 5% of that; 7A at 12V and most of the time not half of that.

Also, you can switch the water heater so count it as a controlled load. My 18kBTU air conditioner pulls 7A at 240V... how big are your two units? You always need to run the two of them? You must be running 40-50 kBTU at that 4.6 kW draw!

The battery charger is also a controlled load like you write. I must admit that I don't know how big your boat is but I always thought that we used a lot of power on our 64' boat with all the gadgets and A/C and washer/drier etc. but you more than double it :-)

ciao!
Nick.
Hi Nick!

Part of the problem is older equipment which is not nearly as efficient as modern equipment. The Air conditioners run about 1.8KW when in air conditioning mode (18,000 btu units) but pull about 2.1KW each when in heat mode and then there is the water pump which pulls another 200 ish watts. Unfortunately the startup surge for these units is very high.

The vessel is an Oyster 55 and with the very large windows in the saloon and originally teak decks the heat load on the boat in the tropics was substantial. However, since the boat was setup for two independent AC systems I can't just run one and keep the temperature consistent through the boat. One unit caries half of the saloon, the galley, aft stateroom, aft head. The other unit caries half of the saloon, the forward stateroom the forward bunk cabin, and the forward head. Because the vessel is so heavy (55,000lbs) all of the bulkheads, cabinetry, etc provide a significant thermal load so if I come home and it is very cold or very hot I turn on both units and it will take them about an hour to pull the boat down to the point where they start cycling. Perhaps newer units would be more efficient.

The fridge / freezer is an old holding plate system with a single 16,000 btu compressor pulling down two huge freezer plates and a single fridge plate. It does not run very much (about an hour per day) so the average power use is about 1/20th of the running power but the nominal running load is rather large.

The boat was originally setup based upon running a generator for an hour in the morning and a hour in the evening to keep the fridge / freezer cold and at the same time charge the batteries / run the microwave, etc.

For example the current charger consumes about 5 amps ( 1150 watts) peak is 7A (1600 watts) to output 30amps @ 26V (780 watts) which is less than 70% efficient! (The peak is at 29V just before the amperage drops).

I have definitely thought about putting a "load sensor" on the input line and if the input load exceeds XXX watts (pick a number) open a relay for the hot water heater to shed the load. But, like your house, I generally don't turn the hot water heater on and off but just let it cycle on it's own.

She is definitely an "old school" boat from 1990.

There are times I wonder if it would be simplier to rip everything out and start over with more efficient / different systems.

For example, I could easily go to 24V constant cycling fridge compressors and evaporator plates rather than the holding plate system. More modern AC units would be nice (although try to find AC units now that can handle 50hz and 60hz in the states! The claim [which I don't know that I believe] is that when everyone jumped to the new refrigerants they made them in 60hz only and 50hz only not combined frequency for the hermetic compressors)

Luckily the average power draw of the equpment is not too bad, I normally run about a $40 - $60 / month electric bill which in southern CA (high electric costs) is not terrible.

Interestingly the boat was setup with dual shore power inputs when the boat was in europe, each was a 32A line at 230V. All of the GFIs in the power panel are rated at 64A. It's interesting, there are 3 GFIs in the main panel, Generator, Shore 1, Shore 2.

This has been the most "interesting" jigsaw puzzle of the boat since I bought it. I had thought that the mastervolt mass GI multitap 7.0 was going to be along shortly and I would buy one, if it was not enough I would parallel a second.

Several of these boats have been retrofitted with an A/Sea system which takes in 10KVA of anything and outputs 9KVA of whatever you program it to output. The 10% loss I can stand, the $18,000 cost for the box which is not a battery charger or an inverter just the converter is a bit steep and it weights about what the charles isolation transformer does (220lbs).

I did find another isolation transformer company in the states who I am contacting that makes a toroidal marine isolation transformer in 2KVA, 3.6KVA, 6KVA, 9KVA, and 12 KVA sizes. Weight for the 9KVA unit is about 100 lbs and can take either 120V or 240V, 50 or 60hz and output 240V power. I have a call into them about if there could be a 208V tap added since they wind them semi-custom. I could run it off the 120V circuit but that would limit me to 50A of input so the 6KVA unit would be the largest. The 9KVA unit would draw about 75A at 120, I would rather run it off of 208 which would draw about 43A...

I wish there had been more standardization of the US docks, the 208 vs 240V issue makes everything a bit of a mess!

Have a wonderful weekend!

David
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Old 12-04-2012, 17:59   #25
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Re: Isolation Transformer: Victron vs Mastervolt vs Charles

Hi
I am fitting out for 18 months in the Med with my US Spec boat and need a switchable 240 VAC/120 VAC, 2.2 - 4.0 KVA isolation transformer. Wilsodf - did you go with the Victron and how did it work out for you?
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Old 12-04-2012, 18:04   #26
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Re: Isolation Transformer: Victron vs Mastervolt vs Charles

Quote:
Originally Posted by kellyp08 View Post
Hi
I am fitting out for 18 months in the Med with my US Spec boat and need a switchable 240 VAC/120 VAC, 2.2 - 4.0 KVA isolation transformer. Wilsodf - did you go with the Victron and how did it work out for you?
The Victron 3.6kW is pretty good, I can recommend it.

ciao!
Nick.
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Old 12-08-2013, 11:32   #27
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Re: Isolation Transformer: Victron vs Mastervolt vs Charles

Sorry to dig up an old thread but I've got a question about isolation transformers. Do they take 220v 50hz European power where it is one leg at 220 and the other at 0 and convert them to 240v 50hz where both legs are 120v?
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Old 12-08-2013, 12:58   #28
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Re: Isolation Transformer: Victron vs Mastervolt vs Charles

Palarran

I just got back from the Med and used a Victron 3.6W for conversion of 220VAC (50hz) to 110VAC (50hz). There's no easy way to convert 50hz to 60hz ( one could use the shore power to run a 220V 50hz European electric motor to power a 60hz American alternator/generator that then supplies 110/120 VAC 60Hz power to run your US 60Hz appliances: compressor motors for refer and airconditioning, etc. This sounds good but I never encountered anyone who actually did this.).

However, the AC and Refrig motors WILL run for a while on 110VAC 50Hz. They are just a bit noisy, get hot and may trip the breaker. As time went on, I found myself using my trusty old 12.5 KW Westerbeke generator to charge batteries and cool down the refer/freezer.
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Old 12-08-2013, 13:49   #29
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Re: Isolation Transformer: Victron vs Mastervolt vs Charles

Thanks Kelly,
I've been using my trusty Northern Lights for two years also. The problem is that my wife is starting to complain about no a/c when we are at a quay. It's not a problem when anchored as we typically get some breeze. Also my refrigeration would benefit greatly from more run time.

The problem as I see it is that my boat is wired as two buss's. Similar to a North American home, you have 120 volt breakers on each leg and when the two legs are combined you end up with 240v. In order to operate the equipment on 240v single leg, I'd need to rewire the buss system or turn off all the 120v breakers when plugged in, and my inverter/charger.

It would be so much nicer to be able to modify my NA shore power socket for a EU power cord that goes into a transformer and comes out like NA power except at 50hz.
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Old 12-08-2013, 14:04   #30
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Re: Isolation Transformer: Victron vs Mastervolt vs Charles

Here are two pictures of my selector switch and distribution panel. I don't know if this set-up is similar to others on the thread. What is nice is being able to select which power source to use for which buss.
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