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phschubert avatar image
phschubert asked

Multiplus 2 weird behavior when running Ninja oven on inverter

Hi everyone, I'm using a Multiplus II in my RV and having issues when running a Ninja Foodi convection oven/air fryer on the inverter. The oven fan, display and light flutters for a few seconds and I can hear a weird noise at the MP2. Voltage at the MP2 goes also wild and the GFCI double socket where the Ninja is plugged in shows scary 109V during this strange behavior. If plugged to shore power, no problems.

The oven can draw up to 1800 watts, but I don't have this issue with other high-current devices like the air condition or when running a small space heater and water heater the same time, which easily draw > 2200 watts.

The MP2 is connected to a 4x100Ah lithium battery bank and wired with 4/0 AWG. The AC wiring is Romex 6/3, also more than sufficient. And nothing suspicious on the battery monitor.

Attached is a video from the VE.bus monitor with audio.

I'm somehow lost now and worried that the low voltage might damage something when I continue to use it off-grid. Any help is much appreciated.

Thanks in advance!

Philipp

Multiplus-II
victron-mp2-and-ninja-foodi.mp4 (757.8 KiB)
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2 Answers
Alexandra avatar image
Alexandra answered ·

@phschubert

The way the convection oven controls temperature does that. It is most likely triac based. It chops up the waveform of the power from the inverter. So the sound you are hearing is bad sine wave and a few other things. These types of electronic controls and victron don't play nicely together. Looks like the GFCI doesn't like it either.

The chopped waveform is the reason why the voltage does not look right. If you measured with a meter it will read differently.

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phschubert avatar image phschubert commented ·

Thanks a lot, @Alexandra ! Seems like I have to live with it then.

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kevgermany avatar image kevgermany ♦♦ commented ·
Is this likely to damage the MP2?
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Alexandra avatar image Alexandra ♦ kevgermany ♦♦ commented ·
@kevgermany

I cannot say for certain, there are too many factors at play. And I know nothing about the particular setup.

It is all about impedance though.(grid has less impedance then the inverter and can absorb the 'noise'). So good battery cables and crimps will reduce the noise. (The newer firmware are better at handling it too)

On my little 24v 3kva my hair dryer does the same thing. We oversized the battery cables running 95mm now and it was reduced alot.


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Alexandra avatar image
Alexandra answered ·

@phschubert

Your instincts are right with regards to the noise. Long term useage it would not be good for the inverter.

And really what would be cheaper? A differently controlled appliance or a replacement inverter?

Does the noise improve with running a higher heat/load? Maybe use it there instead in the meantime. Or just use it on grid only.

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