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ettienne avatar image
ettienne asked

MultiPlus II AC-OUT 2

Could someone kindly please direct me to a detailed explanation of the functionality of the MultiPlus II AC-OUT 2.

I understand it is a direct pass through with sensor from AC Input and suggested use is for high demand items and there is a power assist function that will kick in when using ESS functionality, but will this source also consume from the available 3000w limit on the MultiPlus II 48/3000/35 unit when AC-in power is available?


Multiplus-II
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3 Answers
nigelfxs avatar image
nigelfxs answered ·

Hi Etienne

Unfortunately there does not appear to be a good overall description of the Multiplus-II (MP2). I was also looking for this information before getting this unit! I think this is partly because the MP2 can operate in many different modes, depending on the user's requirements.

A typical use case for the MP2 is as follows:

  • Grid connected to AC-IN
  • "Essential" loads on AC-OUT1
  • Non-essential loads on AC-OUT2
  • The "ESS Assistant" function configured to limit the amount of power that is used from the Grid (e.g. when battery/solar power is available).

Note: When the Grid is available on AC-IN, an internal relay directly connects AC-OUT1 to AC-OUT2. In this the MP2 sees AC-OUT1 + AC-OUT2 as a single load. If the Grid fails, then AC-OUT2 is disconnected and is not powered at all.

The total MP2 "internal" power (i.e. from battery/solar) available to AC-OUT1+AC-OUT2 is 3000VA or 2400W. If the total power required by AC-OUT1+AC-OUT2 is more than 3000VA/2400W, then the MP2 will import the difference from the Grid.

In practice this works nicely. if you have a high-power appliance (e.g. 4000W) connected to AC-OUT2, then the MP2 will use 4000W-2400W=1600W from the Grid. It is important not to connect high-power appliances to AC-OUT1 since these would trip the MP2 if they were used during a Grid failure.

I hope this makes sense!


See https://www.victronenergy.com/upload/documents/MultiPlus-II-to-MultiGrid-and-MultiPlus-comparison-EN.pdf for more info.

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ettienne avatar image ettienne commented ·

Thank you for the detailed explanation. So if I understand correctly you are not limited to 3kva or 2400W of power on AC-out2 while the grid power is available. This will be the same than using your normal distribution board. The only difference is that you have the option now to use power assist.

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nigelfxs avatar image nigelfxs ettienne commented ·

Correct, AC-OUT2 will not be limited to 3KV/2400W, but will be limited by the Circuit Breakers that are required on AC-IN and AC-OUT2.

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ettienne avatar image ettienne nigelfxs commented ·

Thank you Nigel. I understand that it will be limited to the breakers. I am not going to use AC-out 2 for now. I was interested to know for when I will be enhancing the system to add a solar charge controller. Just for interest. I am using a 32A breaker for AC in and a 62A earth leakage for AC out 1

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ettienne avatar image ettienne commented ·

Thank you Nigel. I understand that it will be limited to the breakers. I am not going to use AC-out 2 for now. I was interested to know for when I will be enhancing the system to add a solar charge controller. Just for interest. I am using a 32A breaker for AC in and a 62A earth leakage for AC out 1

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ejrossouw avatar image
ejrossouw answered ·

Hi Ettienne From below, I interpret it as being a "branch"off AC1 with the only functional difference in it disconnecting (zero supply) when switching to battery when AC is lost and best used for non critical loads / high consumers like water heaters. I stand to be corrected on my interpretation.

"AC-out-1

The AC output cable can be connected directly to the terminal block ‘AC-out’.

From left to right: “N” (neutral), “PE” (earth) and “L” (phase)

With its PowerAssist feature the Multi can add up to 3kVA (that is 3000 / 230 = 13A) to the output during periods of peak power requirement. Together with a maximum input current of 32A this means that the output can supply up to 32 + 13 = 45 A.

An earth leakage circuit breaker and a fuse or circuit breaker rated to support the expected load must be included in series with the output, and cable cross-section must be sized accordingly.

• AC-out-2

A second output is available that disconnects its load in the event of battery operation. On these terminals, equipment is connected that may only operate if AC voltage is available on AC-in-1, e.g. an electric boiler or an air conditioner. The load on AC-out-2 is disconnected immediately when the Quattro switches to battery operation. After AC power becomes available on AC-in-1, the load on AC-out-2 will be reconnected with a delay of approximately 2 minutes. This to allow a genset to stabilise."

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ettienne avatar image ettienne commented ·

Thank you very much for the detailed explanation.

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albert-vd-westhuizen avatar image albert-vd-westhuizen commented ·

Hi All Is there programmable control of the internal contactor on AC-Out-2 on the MultiPlus-II? Would be useful to, for example, keep closed and power connected loads as long as battery SOC > 80% but open when not.

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Daniël Boekel (Victron Energy Staff) avatar image Daniël Boekel (Victron Energy Staff) ♦♦ albert-vd-westhuizen commented ·

Hi @Albert vd Westhuizen

Yes on all but the oldest multiplus II models, you can program the behavior of the ac-out2 connection.

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frank-ster avatar image frank-ster albert-vd-westhuizen commented ·

hello, i would like to run the ac 2 out to a water heater, but only to have it activted when the inverter demand is less than 1600 watts . if any other house loads turn on the ac2 out should turn off and only back on if for more than 5 min of loads below lets say 900 watts .. could i program this ?

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trip-tracks avatar image trip-tracks frank-ster commented ·

@frank_ster, yes, this functionality can be programmed using assistants.


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frank-ster avatar image frank-ster trip-tracks commented ·

yep thanks ! i finally figured it out ..

used programmable relay,

--> start assistant

relay -1 progammable relay

use acout 2 relay

set relay on

ac load

when- load- lower than 900 w for 30 seconds

relay -2 progammable relay

use acout 2 relay

set relay off

ac load

when- load- higher than 1800 w for 5 seconds



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mobile-solar-consulting avatar image
mobile-solar-consulting answered ·

When using 2 Multiplus Inverters (specifically in this case the 12V 3000W Multiplus II - 2x120) Is it necessary to combine AC out 2 terminals in parallel?

Customer has a water heater (120V 15A) that runs only when shore is available. Customer is adding a second multiplus, but the total load on AC out 2 is only 15A @ 120V. Customer is combining AC out 1 from first and second multi, but was not planning to combine AC out 2 from first and second multi. Is this OK?

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