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atarlecky avatar image
atarlecky asked

Help with Isolation Transformer and Quattro Voltages

We are in a marina in the Dominican Republic that provides a very clean but high voltage of 135.6 volts at the pedestals. Obviously, this is higher than spec but they say they do it so that everyone on the docks has the voltage needed for their vessels.

The problem is that our Victron Isolation Transformers take that 135.6 voltages and add an additional 5% per its specifications. This new voltage of about 142 volts is obviously quite high and exceeds the Quattro maximum input voltage by two volts - having the result that it won't then start the charge our batteries.

Looking for solutions here.

MultiPlus Quattro Inverter ChargervoltageIsolation Tranformer
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3 Answers
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sharpener answered ·

I don't know the product but can you turn the trafo round so it gives you 5% step-down instead?

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pwfarnell answered ·

There are quite a few threads on here about this. These say that you can swap the primary and secondary coils around. This is also stated as a service centre change. There are no details posted for diy swapping of the coils.

In my marina, nominally 230V the supply is around 253V so with the step up at low load I have 265V which just sneaks in so I have not changed mine around.

The downside to changing around is if you also hook up in other locations when you travel. The transformer is +5% voltage at low load, but when it is at high load the voltage drops down by 6% or so. If you ended up somewhere with a low voltage and you had reversed the coils you could be down to 90V under high load as you have 5% plus another 6% step down. This is why I have not changed mine. However, if you only hook up in the one place then this would be a valid change.

I do not know the Quattro range as I have a Multiplus, can you change the max voltage setting up by 2-3V.

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sharpener answered ·

Sounds like the OP is permanently based in the marina that has the high voltage, so swapping the trafo round would give a max drop under load of 11% which will still be within the limits.

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pwfarnell avatar image pwfarnell commented ·
I believe it is not as easy as just connecting the device in reverse as the Victron IT has other circuitry such as soft start and I am not sure that the earthing internally would be correct although it would still be isolated. This is why it is recommended that the coils are reversed within the device.
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