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journeyoutloud avatar image
journeyoutloud asked

Multiplus shuts down when trying to use Air Conditioner 24/2000/50

Hey all,


I just setup my Multiplus 24/2000/50 Compact and all seems to be working fine until I tried to turn on my AC.


while leaving the Multiplus in “on” position and plugged into 30amp shore power I turned my AC on and the surge when the compressor turned on made the multi shut down.


I have had my rig parked in the same place for the last 4 months and have had to run my Air con a few times before I setup the Multiplus.

I also tried to run it while my generator was running and that didn’t work either. But I used to run my Air Con off the generator no problem before.

I do have to switch on the “weak AC” setting to get the generator to work but still won’t allow the Air Con to work.

Should I be running the multi on “pass through”? (not sure how to set that yet)

Do I have something wrong in the settings?

does the Victron only allow me to use 2000 watts when I am connected to shore power? (Doesn’t make sense to me)

My generator is 4000 watts and still doesn’t let it happen.


I tried it with everything in the rig off except the Air Con and it still didn’t work.


I am running a 24/2000/50 multiplus compact and a 24 volt 206ah prismatic battery set from LYNX batteries out of Washington state. The battery connections use 4awg wire. Battery is rougly 2 foot away from the multi.

Is the only way to make this happen is to get a soft start for the air con?


MultiPlus Quattro Inverter ChargerHelpAutotransformer
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checkit avatar image checkit commented ·

@Journeyoutloud The Multiplus 2000 is rated at 1600W continuous and 2000VA, not 2000W. The inrush current on the compressor can be up to six times the steady state current.

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journeyoutloud avatar image journeyoutloud checkit commented ·

Sounds like you are telling me the multi I have doessupport an Air Conditioner compressor spike load... even when plugged into shore power?


what’s the point of this thing then.


The multi I have is the bottle neck? Only allowing a maximum flow through it?

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checkit avatar image checkit journeyoutloud commented ·

Those specs apply when inverting. When connected to shore power, the transfer switch is rated at 30A@230V or 50A@120V. If your compressor exceeds that rating at startup, it will overload the multiplus.

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journeyoutloud avatar image journeyoutloud checkit commented ·

Got it. This is helpful.

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klim8skeptic avatar image klim8skeptic ♦ commented ·

Multiplus generator FAQ. Some useful reading regarding generator usage.

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5 Answers
bjorn-n avatar image
bjorn-n answered ·

Air conditioning units are "notorious" for demanding a high start-up current. Even though the MultiPlus' 2000 VA rating is enough to run the airco in "steady state", it is apparently not enough to deliver the high start-up current.


I suggest you look for information on an "air conditioner soft start" device that will reduce the start current of the air conditioning unit.

Or, if you're knowledgeable enough in the area of electronics, do some measurements and get yourself big enough capacitors to deal with the short lived high startup current.

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journeyoutloud avatar image journeyoutloud commented ·

Thank you. I have looked at getting the soft start for the air conditioners.

Looks like an expensive try but worth it.

Appreciate everyones help. I will try all of these suggestions and update what i come up with.

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cleaver avatar image
cleaver answered ·

2000 w may no be able to run the A/C. especially if anything else is running. I had to start fan first and let it settle for 20-30 sec. then turn on a/c. If you have power assist turned on, you might want to turn that off and try.

I installed the easy start from micro air. And installed 4/0 wire for my 12/3000 multi. But mine is 12v and requires large wire.

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journeyoutloud avatar image journeyoutloud commented ·

So the Multiplus limits the amount of available power I have?


I thought it would allow the shore power and/or generator power to pass through as if it were just connected to the shore power or generator directly...

Perhaps I should turn off inverter and charger and give it a try?


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cleaver avatar image cleaver journeyoutloud commented ·

I originally had to small of wire. And I turned on power assist, thinking it would allow me to run my a/c on a 15 amp house breaker. It will help but I had too small of wire and it causes overload instantly.

Even though the multi was capable. The load was 100+ amp DC@ 12vdc and the power just couldn't get to the inverter from batteries. One other thing to check is. What is the power flow rate of your battery. I'm not familiar with prismatic batteries.

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journeyoutloud avatar image journeyoutloud cleaver commented ·


I will look into the batteries more. I will give it a try with power assist off and see if that helps.

I may upgrade wires an shorten the distance a bit at the same time. Probably tomorrow.

I have seen people talk about pass through mode on a few of these threads. Have you heard of this or turned on this feature?

Does this give you the ability to just bypass the inverter and battery charger to get full power to the rig?


thank you.

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seb71 avatar image seb71 journeyoutloud commented ·

Do you have any specifications for that air conditioner unit?

I am just curious.

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journeyoutloud avatar image journeyoutloud seb71 commented ·

The rear is 15,000 btu and the other is 13,000 btu in the front.


both are dometic.


I figured it all out though.

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cleaver avatar image cleaver journeyoutloud commented ·

Unfortunately I don't have a video of the A/C before the installation of a micro air soft start but I have 2 videos of it running with generator and one with battery alone.

https://www.youtube.com/watch?v=VCl4SFmn-Qw (with generator)

https://www.youtube.com/watch?v=EUdLrftA3EA (battery alone)

That is a 15k btu A/C dometic.

Almost a guarantee that you will need 4/0 cables if you want to run an A/C on battery alone. Like I said before, I'm not sure what the output of the inverter is. But Bjorn-n gave some details above.

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alan avatar image
alan answered ·

If the prismatic cells are LFP, they will give 2C discharge. So 412A. But are they individual prismatics linked in series? or run through a BMS? or even worse a built in BMS? What is the BMS's surge capability?



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journeyoutloud avatar image
journeyoutloud answered ·

Hey all, I found a fix.


thank you guys for all your help. Between this forum and calling tech support of the dealer I bought this from I have figured out what I need to do to make this work correctly

My rear Air Con is 15000btu and I have to get a soft start for it. No two ways around it.

The 13000 btu air con will run from both 30amp shore and 30amp generator without the soft start (although I will put one in it too)... but, you need to tweak some settings... to get the ac to start and through the compressor load I have to turn of the charger on the Victron and turn off UPS.

I have hooked up the Victron to my laptop using the Victron connect app (not the config app) and saved a few important setting profiles to easily switch on and off certain settings when I need to use them.


for instance, running the generator I have settings saved that turn on “weak AC” for my generator profile to use for normal generator operation. And then I saved another profile for running the generator and starting the Air Con.

And many others (make sure you save your baseline settings too)


all I did from there is emailed them to myself and opened them on the Victron connect app on my iPhone and saved them to the settings profile manager.


map now when I need to do certain things like start the air con I can flow all of the power to it.

One of the big things is that I had to many amps going to the batteries from the charger set. This was drawing a lot of power from my usable power. I have a setting to turn that down to like 15amps from 37amps.

This helped a lot too.


I think I have figured out how to make this work for me now. Thank you all.

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aaronca250f avatar image
aaronca250f answered ·

Image (3).jpegImage (4).jpeg

When my smart dongle shows AC in leg on my air conditioning unit will function. If the smart dongle doesn't show the AC in leg, but only displays wattage the air conditioning unit when turn on will shut off all AC 120v in the trailer. What does it mean when the AC in leg isn't lit up?



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