I can’t use shore power with my isolation transformer in two marinas in Mexico (so far)due to most marinas seem to have 131 volts to 133. Hotel Coral in Ensenada and Puerto Los Cabos don’t allow me to use shore power. Both marinas read 131v at the outlet. I am headed to Mazatlan and Puerto Vallarta in the next few weeks, so will post if this is an issue there as well.
Seems like someone at victron should weigh in on a more formal solution, or should warn users that a Victron isolation transformer will leave them powerless outside of the us. I have read a few cruising forums where others haven’t been able to plug in and get power due to this issue.
Is there a way to re-wire the isolation transformer to lower the volts 5 percent to resolve this issue?
Something to ponder.
I had an iso transformer on my old boat that was never used at full capacity of 16amp.
With the primary voltage at 230v the secondary would be at 240v with no load. Even with my maximum load 8amps it only dropped a volt or so. Whist this was ok at 230v when encountering 249v which is common over here it would give 259v out, which was outside the acceptance voltage of my Victron combi.
The solution was to reverse the primary and secondary so with 249v in I got 239v out. Yes I lost some of the regulation but the voltage drop was minimal and at least I had power.
Eventually I wired in a change over switch so I just switched for low or high voltage.
However you do need to know how it all works in order to wire the grounds correctly to preserve the isolation on the transformer.
We were able to connect in Marina Coral, but that may just have been the particular dock we were on was not quite as hot. We have been in Marina Mazatlán (Pier 6) for a week now however and are dealing with this issue. Pedestal reads 131-132V, isolation transformers are boosting to ~143V, snd MultiPluses are rejecting the power.
What I would do, but this is me and I don’t encourage others to do the same if they don’t feel confident…
Being an 1:1 isolation transformer, you connect them other way around.
Meaning connect pier power to output of transformer and get the power for boat from the input of transformer.
If this is true and the transformer slightly is raising the voltage, you will get then a slightly lower voltage than the pier voltage.
This is wrong with the Victron isolation transformers because they are not simple isolation transformers. The soft start will be on the wrong side of the device for one thing. Secondly, you will loose your galvanic isolation on the ground line leaving your boat open to galvanic corrosion as the case is connected to the output ground and to the boat ground.
Alex, please only give advice on equipment you know the detail of not what you think it is.
I’ve already said that this is what I (as in myself) would do and not encourage others to do.
As per the rest of your points, those are details and any person which has passed through a high school will know what to do in order to reverse the wires inside the equipment, moment in which all your worries will not hold anymore.
Otherwise is just a tax paid for “ignorance”, to put it mildly.
I am fully aware of the post I linked to swapping the transformer coil connections, I have looked inside my IT as one marina was close to limit. However, doing this preserves the soft start and galvanic isolation so is correct.
Just swapping the input and output connections per your post is not going to work without further wiring mods which are not obvious. Do not assume people understand what to us are basics.
OK. Sorry that I didn’t make myself understood better. English is not my primary language.
I was referring to the transformer windings, when I’ve said “connect the pier to output of the transformer”. Didn’t say output of the device.
I had in mind the transformer inside by itself as a single component and the transformer windings and their swapping.
Yes… that did the trick! It’s a small world… Mike is actually a good friend of ours who has sailed with us previously. I did not know their new boat had the same isolation transformers and that he had solved this issue.
Thanks for this, I am in a new marina in the UK and my incoming is 250V (max allowed is 253V, 230V + 10%) so my IT is 263V outlet at low load, the Multiplus isolates at 270V. I think I will get around to doing this, I had an idea what to do, you have confirmed it.
