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maxtosea avatar image
maxtosea asked

Running water heater/ washing machine or Air con off batteries ?

I'm trying to use my water heater/washing machine/air-conditioning when not connected to shore power. Previous owner had a switch that combined both breaker boxes together so that when not connected to shore power it will run. But now it's just trips

I've recently added Four 330ah life-po4

2500w solar panels

Two 12/2000 80/30 multiplus in parallel

So it should have enough power to run off the batteries but keeps tripping the breaker

I've even tried to add assistance via main relay to turn on at 99% SOC and off at 94% SOC

It would work for a few minutes but ultimately it trips


Can someone tell me what am I doing wrong?




multiplus in parallel
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3 Answers
snoobler avatar image
snoobler answered ·

When on shore power, the inverters are in passthru mode, and they can pass far more power from shore than they can deliver when inverting.


What breaker is tripping?

What is the draw of the A/C?

What is the draw of the water heater?

What is the gauge of your battery cable?

What is the length of your battery cable?

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maxtosea avatar image maxtosea commented ·
Main breaker is tripping

Water heater is about 900w

Ac is about the samei( not running both at same time)

I would say battery cable is 16 gauge. They are really thick and is about 1- 1.5 meters long

Before I added the lithium , extra solar and extra Multi it was working. I was thinking that when I reconfigured the system I missed something.



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snoobler avatar image snoobler maxtosea commented ·
"Main Breaker" isn't helpful. Where is the breaker, and what is its rating?


If you mean 16mm^2 cable, that's woefully thin. If you're estimating the diameter of the cable as 16mm, that's probably adequate, but it would be good to know the actual gauge. It's usually printed on the wire.


With 2X 2000W MP running in parallel at max draw, you could easily pull over 400A. You need suitably rated cables and breakers or fuses.


It's very important that all of your connections are properly torqued and of high quality. It's very important that you've followed all best practices in wiring two MP in parallel per Victron's Wiring Unlimited.



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maxtosea avatar image
maxtosea answered ·

So i have 2 breaker boxes top 1 which handles the hot water heater washing machine and air conditioning and the bottom 1 handles the 220 outlets on the boat. If I'm plugged into shore or generator both work but when disconnected only the bottom works.The previous owner installed a breaker that combined the 2. I'm just trying to get both to work while being off shore.

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JohnC avatar image
JohnC answered ·

Hi @MAXTOSEA

I suspect something grounding related (especially with a hws).

Bear in mind that (by default) the Multi will make it's own Neutral/Earth link when ACIN is vacated. This can be turned off, and may well be related to your issue.

I'm unqualified to give AC advice, so don't..

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