Voltage too high for Victron Iso Transformer

[Mycroft]

I've run into a problem with my Isolation Transformer from Victron. If the shore power voltage is over 126, it fails to work because the voltage is too high. Anybody know of an inexpensive way to reduce the voltage to below 126?

[CarstenWL]

... how much power do you need on 110V?

Basically you need a step down transformer (like the 3kw here: https://tinyurl.com/ycyupx7c)

If you have 'heavy loads' like AC or so you will need bigger ones.

What type of Victron do you use? Normally they shut off at 130V ...

Carsten

[hellosailor]

You might check with Washington state and the power company. In the US, mains voltage is generally 117VAC plus or minus 10 percent, by law. That could mean 128.7 VAC is normal, predictable, legal power. And that if the Victron was unable to handle that, it should never have been sold in the US market. A good argument for a refund from Victron, regardless of the age or warranty status.

The local power company MIGHT be willing to do something about reducing the mains voltage anyway, because that's just pushing the boundaries of what should be expected. Among other things, every filament light bulb on the premises will be burning out too quickly. Anything over 120 is abnormal and unacceptable, IMO.

[GordMay]

“... Supply 88 V – 130 V: switches to 115 V supply ...”
➥ https://www.victronenergy.com/upload...formers-EN.pdf

[hellosailor]

Gord, you may have missed the context here. That Victron page actually says:

"3600 Watt Auto 115/230 V
This model will automatically switch to 115 V or 230 V supply, depending on input voltage. Supply 88 V – 130 V: switches to 115 V supply "

But there is no rating for the 2000W model. That may be what the OP has an issue with.

[CarstenWL]

... also the 'single voltage 110V' Victrons will switch off at 130V ...

Carsten

[Mycroft]

Actually, that is the model I have, the 3600W Auto. Yes, up to 130v, it switches to 115 but at anything above 126v, it will not stay on. I didn't run into the problem until about two years after install. Now consistently from Port Townsend on down the coast, we're running into marinas with >126v. Here in La Paz, it's 128v.

Needless to say, I'm very unhappy with Victron. I'm going to try talking to their support again, now that I've run into the problem more. But that is very difficult in the US. Their Charger/Inverter has no problem with 128v, but the ISO sure does.

[S/V Alchemy]

Originally Posted by Mycroft

Actually, that is the model I have, the 3600W Auto. Yes, up to 130v, it switches to 115 but at anything above 126v, it will not stay on. I didn't run into the problem until about two years after install. Now consistently from Port Townsend on down the coast, we're running into marinas with >126v. Here in La Paz, it's 128v.

Needless to say, I'm very unhappy with Victron. I'm going to try talking to their support again, now that I've run into the problem more. But that is very difficult in the US. Their Charger/Inverter has no problem with 128v, but the ISO sure does.

Good to know. I just installed the 3000Kva charger/inverter, but I have never seen input (mains/shore power, etc.) voltage about 124 V here in Toronto. I find 128V a little excessive and I wonder if that would damage some of my other gear were I to go "straight". I'm sure there's a solution to step down the AC to 120V to avoid this.

[Cadence]

Originally Posted by S/V Alchemy

Good to know. I just installed the 3000Kva charger/inverter, but I have never seen input (mains/shore power, etc.) voltage about 124 V here in Toronto. I find 128V a little excessive and I wonder if that would damage some of my other gear were I to go "straight". I'm sure there's a solution to step down the AC to 120V to avoid this.

I simple buck boost transformer And can act as isolation.

[Mycroft]

Achemy, I agree, and as I said, we've run into it on multiple occasions. I finally just bypassed the iso-transformer completely.

Cadence, if you could provide a link to a buck/boost transformer that can bring 125-130 down to 120 and also handle 30amps for months at a time, for less money than a new iso-transformer, I'm all eyes! Most transformers that I've seen are designed for 115v/15a stereo equipment etc. and not cheap or designed for short-term use with fans required to dissipate heat.

[Redline452]

Do you have a (or several) really long shore power cords? They won't reduce voltage without a load, but when we're at the far end of a dock needing all four of ours, there are definitely fewer volts reaching the boat.

[mrm]

Originally Posted by Mycroft

Anybody know of an inexpensive way to reduce the voltage to below 126?

An anti-parallel string of rectifier diodes should do the trick, but consult a professional electrician to assemble it. And yes, it is not a _proper_ solution, but will get you going until you find a better one.

[Redline452]

A Hammond 1182T12 transformer ( $106 CAD at Digi-Key ) with its two secondaries in parallel, then in series bucking the input, would reduce the line voltage by 12 at up to 25A. But it sounds like the voltage sensing in your Victron has gone astray.

Another thought - doublecheck all grounds, neutrals, and all connections. Perhaps a leakage condition or similar is causing just enough current at the higher voltage to cause a protection trip?

[hellosailor]

In theatrical lighting and a few other niches, an "autotransformer" common brand name Variac, is commonly used to dial back the AC voltage. Usually a red "can" with a voltmeter on it and a black knob on top, you just dial down the output voltage with the knob. The catch is, one side of the circuit is always hot so it is possible to have lethal fault. But that doesn't stop them from being used.

https://www.ebay.com/itm/20-AMP-110V...MAAOSw4A5YwiYD

Here's a cheap one rated 20A on ebay.

[BobHorn]

Neither a buck-boost transformer or Variac will provide isolation.