Inverter Running Despite Absence of Load

[hummingway]

I went to the boat for a sail last week and the house batteries were drained. When I leave the boat I throw the main breaker for the 110 side of things so I presumed it was draining off of something 12v. I fired up the engine and went sailing bringing her back with full batteries. When I went back to check after two days the batteries were drained again. I ran the gen and charged them then began to go over things.

I noticed that despite the panel being off that the Victron Multiplus inverter was running. The 110v output from it goes straight to the main breaker which was off. I turned the inverter off. Then left things a couple of days. Yesterday I went out for another sail - the batteries had held their charge. I've been using the Victron for close to a year and hadn't noticed the inverter ever running without a load so presume that it "thinks" there is a load.

I haven't pulled the panel yet. Is it possible that corrosion could be causing this? Am I correct in believing that the Victron shouldn't be running when there is no load or do I need to be turning it on and off as required? Has anyone seen this behavior?

[S/V_Surya]

Not sure about the Victron but even with no load on 110 side the inverter will be pulling amps from batteries. Overhead from active circuits in inverter.

[hummingway]

It's possible I haven't noticed it before because the solar panels were able to keep ahead of it's draw. We're into the the short days of winter, low angle of sun and rainy season to boot. Not many amps being produced now!

[Blue Stocking]

Not sure about Victron, but the Hearts had a programable "load-seeking" feature. If it was switched on, you would see the amp gauge jump at a timed rate.

[CharlieJ]

What circuit breaker are you referring to when you state "...I throw the main breaker for the 110 side of thing..."?

Charlie

[hummingway]

The breaker that feeds my 110v system. It's fed the output from the Victron inverter.

[capn_billl]

I switch off the 12v side when not using. The sensor circuits use a little power constantly. My Xantrex uses 1 amp when in idle.

[btrayfors]

According to the Installation Manual, the MultiPlus draws about 7.5 watts (0.6A) DC when in a no-load condition. That's a bit over 14AH per day. In a week it would be over 100AH.

In any case, you should turn your 12V DC to the inverter off when you leave the boat. Or, you can turn the MultiPlus off using either the rocker switch on the front of the unit or the Remote Control, if fitted.

Bill

[capt_douglas]

My Heart 2000 manual said that as long as the unit was on, it drew about 100ma. The reasoning was that the inverter needed to sense when a load was applied and the electronic circuitry needed to be kept alive.

After reading that, I turned the inverter on only when I needed it. Sort of like turning the lights and fans off when you leave the boat.

[hummingway]

Thanks guys. It looks like that's what I'm doing from now on.

[capt_douglas]

We all make mistakes. The real trick is to make them once.

[djmarchand]

Originally Posted by hummingway

The breaker that feeds my 110v system. It's fed the output from the Victron inverter.

Are you sure that is the case. A proper inverter installation will feed shorepower to the inverter from that main breaker and then the inverter output will go to the subbreakers that are isolated from the main. The few loads that you don't want to be fed from the inverter- AC and water heater are tied to the main breaker but all others are fed from the inverter output.

Xantrex's site has a good installation diagram of how to do this.

So the inverter could still be seeing A/C load if it is wired as above.

Xantrex inverters and presumably others have a feature that lets the inverter start up briefly, if it sees more than a few watts of AC load it stays on, if not it turns off. My Xantrex inverter would pull about 1/2 an amp when on but no load and the load sensing feature not enabled.

David

[hummingway]

I'm sure that's how it's installed. There are no loads not on the inverter.

[gonesail]

my inverter has an ON/OFF button .. i have never turned it on while connected to shore power but i am guessing it would not work in that case.

[hummingway]

Originally Posted by gonesail

my inverter has an ON/OFF button .. i have never turned it on while connected to shore power but i am guessing it would not work in that case.

That's the way the Victron works. It's a charger and inverter, can be switched to charger only or turned off. It detects shore power and I mistakenly presumed it would detect a load as well. Apparently not!