question

pondee avatar image
pondee asked

Multiplus see's AC in, but doesnt 'latch'

I have a multiplus which see's the AC input (voltage and frequency) when it 'clunks' about 10-15 seconds after ac is turned on the power doesn't pass through? It then tries again several times but still doesn't work.

The unit works fine in invert mode but I haven't been able to charge the batteries or use the supply input to pass through the unit?


multiplus ve.bus
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kevgermany avatar image kevgermany ♦♦ commented ·
What's the source of AC in? Grid or generator?

What are the AC input settings on the multiplus?


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pondee avatar image pondee kevgermany ♦♦ commented ·

It's on a boat so shore power/ grid.

The boat is 230v 50hz, but it's in the US


Settings wise the input is restricted to 19a as the boats wiring is CB'd @ 20A

20231215-195552.jpg

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5 Answers
snoobler avatar image
snoobler answered ·

U.S. shore is 120/240VAC split phase with a center tapped neutral and bonded ground.


230VAC/50Hz has a single L and N with ground bonded to N.


I don't know the EU stuff well enough to say for certain, but I suspect THAT's the issue - the ground is generating current where it shouldn't.


I know for certain that attaching 230VAC single phase power supplies will NOT function properly when connected to L1, L2 and G on U.S. split phase.

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kevgermany avatar image
kevgermany answered ·

I think you'll have to fit a transformer. As @snoobler points out, you're playing with your life here

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pondee avatar image
pondee answered ·

The units removed were Victron phoenix inverters and separate 'other' brand chargers. These have all been removed and replaced by these multiplus units.

There are 2 of these multiplus units working in parallel; I've gone back to basics and just trying to get one of these running to confirm it works, then I will parallel them back together... again one unit is working successfully as an inverter.

Even using the generators input this doesnt latch the pass through power?



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snoobler avatar image snoobler commented ·

Even using the generators input this doesnt latch the pass through power?


Why are you asking us? Does it work or not?


Again, EU spec equipment isn't typically compatible with North American split phase.


The only way you can guarantee it to work is to ONLY connect grid L1 and L2 to inverter L and N with no ground or neutral connected. Unfortunately, this is dangerous as your system isn't grounded. You could be electrifying the water or have dangerous voltage on any ground-connected metal.


IMHO, you need a separate charger compatible with north america power.

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pondee avatar image
pondee answered ·

So... I found the generator L1 and N had been incorrectly wired from day 1.


Then once this was resolved I removed the rcd from its output, to leave only the rcd after the multiplus. Voila!


As mentioned above we can't seem to run these inverter chargers from the dock power supply, guess that's just one of the quirks of the system really?

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snoobler avatar image snoobler commented ·
Glad you got that part sorted.


I would not call it a quirk. It's the result of trying to power one system with an incompatible power supply.


US residential power is 240V/60Hz - similar to EU 230V/50Hz, BUT it's center tapped neutral for two legs of 120VAC as well, AND that's where the ground is placed - halfway between the 240V legs. EU power requires N-G @ 0V and L at 230VAC.


Again, if you can connect to ONLY the L1 and L2 of the shore power (no ground or neutral) , I expect you can configure the inverter to connect, pass through and charge... but I can't say what that would do to safety associated with a "hot skin."

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pondee avatar image pondee snoobler commented ·
Tomorrow I will check through the shore power cable and inlet into the boat. I'm thinking similar to what you've said above


US L1 to Live

US L2 to Neutral

US ground to Earth

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snoobler avatar image snoobler pondee commented ·

The above is highly unlikely to work, and if it does, it may not be safe. Your equipment expects N to G of 0V. In your proposed config, there will be ±120V between ground and N due to the aforementioned center tapping of North American power.



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pondee avatar image
pondee answered ·

You guys are correct. It doesn't work with US power.

What's weird is that the Skylla-I charges the batteries, same spec voltage and frequency wise as the other kit. It's not a complaint as here in the US I can use this to charge the batteries and use the multiplus units to give me inverted battery power.


I basically rigged the shore inlet power to the output of the generator and proved that the shore inlet cabling is correct through the rest of the boat.

I'll put this to bed and thankyou guys for your input, its appreciated.

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snoobler avatar image snoobler commented ·
GUESS: It probably works because it has no internal N-G relationship and is only grounded at the case, i.e, there is no internal circuitry associated with the ground, and it's happy with the L1/L2 input.
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