question

jefndeb avatar image
jefndeb asked

MultiPlus drops offline 10 seconds when AC kicks on..

Looking for suggestions-

We have a Kohler 8k marine genset and while running our 16k dometic AC pack, (when at anchor,) i notice that each time the compressor kicks on, our Victron touch screen GUI indicates that our shorepower/Genset feed drops out for about 10 seconds and then comes back online.

The shorepower and/or generator feeds go thought the Victron Multuplus 3k Inverter/Charger as it normally is designed..

This "trip" seems to follow when the compressor cycles from off to on.

Is this an indication that the capacitors on out genset are going out?

Not really sure if these capacitors are used in a way to buffer a spike or not.

I'm not really to sure of I'm close on my thought pattern here but just wanted to ask for suggestions.

Would be glad to hear ideas but I do have the Dynamic Current LImiter set to On and it makes no difference.

Maybe its the water pump cycling on that doing this?

PS, Our Air Conditioning system is 240vac

Appreciate your ideas...

inverter current draw
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klim8skeptic avatar image klim8skeptic ♦ commented ·
Sounds like the input ac current limit has been reached, and the multi is going into power assist.

More information needed.

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1 Answer
Kevin Windrem avatar image
Kevin Windrem answered ·

Dropping the AC input is most likely due to a dip in voltage or frequency when the air conditioner compressor starts. The 10 second time is in line with how long the Multi takes to resynchronize to the incoming AC input. (Before it can again close the AC input relay the Multi's voltage and frequency and phase must match the incoming AC waveform.)

During this short period, you will be running on batteries which shouldn't cause a problem unless you are already loaded beyond what the Multi can supply on it's own.

You might look into a soft start unit for your air conditioner. I use the MicroAir version but there are others. A soft start will reduce the starting current try 60-75% (MicroAir's number). With it, I hardly notice the compressor starting.

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