mrkjamesbb avatar image

Multiplus shuts down while plugged into shore power on “charge only” mode


I have a Victron Multiplus Compact 12/2000/80 inverter/charger.

I use it in my travel trailer with solar panels and battleborn batteries.

I wired the inverter’s “AC out” into the trailer’s breaker box and the shore power cord on the trailer into the inverter’s “AC in“ in order to take advantage of the built-in automatic transfer switch.

I only plug into shore power when I need to use the trailer’s air conditioner. When plugged into shore power, I switch the Multiplus to “charge only” mode as my battery bank and this Multiplus will not power the air conditioner if shore power is lost. It’s start up requires around 4,000 Watts.

However, sometimes when I’m plugged into shore power, the Multiplus will turn off for a few seconds, killing the AC power, and then turn back on again even though shore power was not lost.

This is inconvenient when trying to sleep as I have to jump up and turn off the air conditioner before the Multiplus turns back on and is suddenly tapped for the large load required by the air conditioner. This results in a loud buzz from the Multiplus and the error light flicking on for a second before it returns to normal functioning.

I’m guessing this happens because the Multiplus has parameters to shutdown temporarily when the shore power current, voltage, and/or frequency drops below a certain amount—something one would not notice if the shore power was not entering the trailer via the Multiplus. I do understand these parameters are in place to protect whatever load device you have plugged in, but for me, it’s a inconvenience.

I’m wondering if there’s a way to change these parameters in order to prevent this from happening.

Please point me in the right direction so I can fix this. I have the VE bus. If you could help me with this, I would be very grateful.

Thank you,


MultiPlus Quattro Inverter Chargershorepower
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3 Answers
harold avatar image
harold answered ·

@mrkjamesbb 3 idea's:

- Did you try to connect you airco at the AC2OUT?

- Keep the Multi on, so for the peak is can 'assist' (and maybe programm an alarm via Asistanst for when the shore power realy is lost)

- You could allso programm assistants for switching on a certain load.


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JohnC avatar image
JohnC answered ·

Hi @mrkjamesbb

It's likely gagging on the aircon 'start spike' because you've removed the ability of it's own inverter to cover it. It will honour it's own passthrough limit, and won't tolerate the spike.

Try leaving it turned just 'on', the functionality will be the same, and that spike will be covered by it's own inverter, right up to it's passthrough limit plus it's own inverter spike capability.

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rickp avatar image
rickp answered ·

If losing shore power isn’t a concern, the MP in the “On” setting will assist sagging shore power to keep everything happy. It’s likely that other high inrush loads, maybe other ACs, are causing the shore power to sag outside acceptable voltage for your MP. The factory setting will accept anything from 94-143 volts, so it sagging (or surging!) outside that range might damage your AC, so it might be a blessing in disguise.

There is also a WeakAC setting for badly distorted incoming voltage. I have not messed with that, but it might be worth reading up on. Also, check to make sure the factory ranges haven’t been narrowed by whoever set the device up initially.

Factory settings are in Section 5. Configuration on page 17 of the online manual.

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There’s no way I’m leaving the MP in “inverter” mode while plugged into shore power with the air conditioner on. If there is a power outage, the inverter will attempt to run the air conditioner with the batteries. This will immediately blow one of my fuses. I’ve had a 250 amp fuse blow before doing that, and now I always stick it in charge only if running the aircon.

I rarely plug into shore power and only need to if I wanna run the air conditioner. The only loads I use are AC fans, AC phone chargers, and a toaster. Everything else is DC. It’s a small trailer.

The turning off while plugged into shore power and on charge only mode happens without the air conditioner on. It’s definitely not turning off because the aircon’s load. The MP is picking up on a sag (or surge) in the shore power and automatically turning off for a few seconds in order to, like you said, protect my load appliances.

It mainly happens at campgrounds out in the boonies and happens less if I use my adapter and plug into a 50 amp plug rather than the 30. I’ve experimented at the same campground.

I’m on the road right now for the next six months and don’t know how to change these settings or what settings to change.

I did recognize the “weakAC” setting as possibly something that may fix this issue while researching today, but I’m not sure exactly what it does. I understand that it works for a dodgey generator but not sure if it’ll also work for a dodgey campground. It sounds like turning it on will allow AC shore or generator power to flow through the MP on charge only mode and into my trailer’s breaker box even if it sags. In other words, there’ll be no need to change any parameters as the weakAC will allow voltages outside of the factory parameters to flow without cutting the MP and, therefore, the power. I think?

Will the weakAC override the 94-143 volts and allow voltage lower than that to flow into my AC breaker?

I installed and set it up. I changed the battery charging settings per battleborn’s instructions. Everything else is factory.

Thank you for your help