question

Hi,

Just an idea (not tested): As you say the ratio is 1,06, then you might change the input with the output side, and thus lower the output voltage.

According to the diagram of the datasheet, there are three points to consider:

1) You would have to remove your earth of the boat from the (removable) N to Earth connection on the (official) output side and connect to the N of the other side, maybe do this outside the transformer.

2) The soft start circuit is on the official input side. Maybe you just could try without the soft start, of your shore power breaker does not trip, otherwise try to add a soft start circuit somehow (or move the internal soft start circuit to the other side). I don´t know if the internal soft start circuit on the (new) output side will affect somehow the output, in this case find a way to deactivate it.

3) If you have sometimes also low voltage shore power, you might want to keep it "reversible", which might it more difficult to implement to have an easy "switchover".

As I said, this is just a thought. Maybe somebody else can comment if that might work or not (hopefully with explanations).

If it's always on the high side it might be an idea to use the IT in reverse...

I haven't dealt much with Victron IT's, but I know others often have multiple in/outputs for + or - 5% to adjust to local voltage.

Thanks tilo & Boekel

Its a brand new transformer, I'd rather not use it outside of intended use and void warranty; and inserting 240V circuit elements (e.g. making a softstart cct) without suitable certification can present as legal & insurance issue here in australia.

Re: using the transformer in reverse, as tilo alluded to there is more to the transformer than just the windings. The number of components on the circuit board indicates there may be some self test and protection functions in addition to the soft start circuit.

I think unless Victron says the 1.06 is outside of tolerances, the solution has to rest with the multiplus configuration. I did find a note that the AC high trigger has a max range of 270v. So a temporary workaround might be to set trigger to 270v.

This workaround would have the issue of no hysteresis and operating above the nominal max of 265v without official confirmation from Victron. Would still like a Victron tick of approval or at least experience from someone who has configured it this way and has a substantial up-time after the mod.

Cheers

If you think your IT might be a case for warranty, contact your dealer.

Here some tips for workarounds in the meantime (which shouldn´t cause warranty or insurance issues):

VEC3 will not let you raise the high voltage disconnect above 270V, those 270V are the limit. And the (re)connect high voltage limit can only be raised to 269V, that leaves you with 1V of hysteresis. This 1V sounds little, but if you really have consumption, for example to charge the batteries, then this consumption will produce a voltage drop, and thus has the effect of an additional hysteresis. The higher your consumption, the more "stable" it will be.

If your system doesn´t connect because you have the high voltage, you might connect a big consumer (water or air heater) before the Multiplus to lower the voltage below the 265V (or 269V), till the Multiplus starts consuming and thus lowers the incoming voltage itself, and then you can remove your "starter" consumption. You also can leave the additional consumer there if you need it, or if you don´t mind that it increases your electricity bill but stabilizes your system at this moment.

Additionally you can use a longer shore power cable with a low cross section to keep the incoming voltage a little lower once there is a current flow (with your "starter" consumer). But beware, don´t leave the "surplus" cable on a roll, because it can get hot and melt (as it happens with any power cable extension left on the roll). And use cables only up to their maximum current specification.