question

thamesrichard avatar image
thamesrichard asked

multiplus 3000/12 ac output wire over heating.

Hello, I have about with the multiples fitted in it, when the boat is plugged in on shore power everything performs normally on the 230v side! but when away from shore power and the 230volt system is used the a/c output wire gets very hot. There are no bad connections and the battery bank running it is 6 x 150amp lithiums, I have checked all the wiring sizing and connections and everything is within spec? any thoughts on what may be causing the wire to get extremely hot?

multiple inverters
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5 Answers
Alistair Warburton avatar image
Alistair Warburton answered ·

That sounds dangerious... The only thing electrically that will heat wier is exess current. Your overload devic should always stop that happening, no matter the cause.

I mean no offence but if you dont have the tools or knolidge to test and diagnise this issue you should get somone qualified to check it ASAP and not use the 230V, at all, untill you have found the issue.

I suspect the last place you want to be when an elsctrical fire starts is off shore on a boat.

In theory, the wire between the inverter and your distribution board should not be able to get hot at all because the inverter would shut down on overload long before that happens. Something is very wrong and is sound serious.

With respect to diagnosis....

Check the current in the wire.
Output voltage and power of the Multi.
Do this with no loads and then all possible loads, individually.

Monitor the temperature carfully when testing, have an extinguisher to hand and do it in port but configured for motoring.

DO NOT do any of this if yu are not 100% comfortable with 230V testing or have to ask what the results shouls be.

Sorry to be blunt but this stuff can kill you in several ways, it isnt something to mess with unless you know what you are doing.


2 comments
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thamesrichard avatar image thamesrichard commented ·
Thank you, I have the tools and knowledge for the 12volt part but I won't get involved in anything 230v as I haven't got the certificates for that and know the harm it can cause, thank so much you for your reply and I don't mind you being blunt at all as its a safety issue.


It is odd that on shore power there is no heat and everything works perfectly! it sort of points to the inverter, I'm going to check all the settings in victron connect later today as this was all set up by the previous owner! if they are correct I will get the marina to check the 230v system out for me.

many thanks for your reply



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Alistair Warburton avatar image Alistair Warburton thamesrichard commented ·
Check the shore voltage is roughly the sme as the voltage the inverter is set to. Supplying devices, other than simple loads, with a low voltage can draw exess current but to be fair it would have to be a huge difference and even then unless the wire is very undersized getting noticible heating is a stretch.


Please post what they find, I am interested to know the cause.

1 Like 1 ·
ludo avatar image
ludo answered ·

You might have a ground loop between the 12v dc and 230v ac wiring, so that maybe part of your dc-current is running over the neutral wire of the ac circuit. Change the ground relais setting in the multiplus and check if you see some change.

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Alistair Warburton avatar image Alistair Warburton commented ·
Good point, I didnt think of that but it is far more likely than a low voltage issue. It would also explain why it isnt happening on shore power when DC currents would be low.
1 Like 1 ·
thamesrichard avatar image thamesrichard commented ·
thank you, I will go through the settings and try and post some screen shots of them.
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ludo avatar image ludo thamesrichard commented ·
I think the problem is foremost in the wiring, only disabling the ground relais ( if set) might have some influence.
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thamesrichard avatar image thamesrichard ludo commented ·
I will re check all the wiring and get the 230v system checked by the marina, its just odd that no matter what is turned on and operated in the boat on shore power is totally fine and the wiring stays cool.
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ludo avatar image ludo thamesrichard commented ·
Not really, as Alistair already noted, on shore power there is only minimal DC usage.
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ludo avatar image
ludo answered ·

Did you find the fault?

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thamesrichard avatar image
thamesrichard answered ·

Hi, I had all the 230v system tested and re checked! all ok and tests passed. Next we removed the inverter and checked all internal connections. Re installed and managed to get the unit to re set to factory settings. Checking the settings they were all the same as factory. Now the unit runs perfectly and no heat is generated on the output wire. Thank you for all your help and advice.

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ludo avatar image
ludo answered ·

Not finding a fault is always bad, it might return. But, glad to help any time

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