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power factor

Can anyone explain why and how the 1.0 factor rule solves the AC coupling problem?

I have read the document "AC-coupling and the Factor 1.0 rule" carefully and I can understand the potential problem posed by AC-coupling but I have difficulty understanding how the "Factor 1.0" rule helps in this situation. This rule is simple: “The max PV power must be equal or less than the VA rating of the inverter/charger”. But I do not understand why this rule fix the problem described in section 2.2 “example and background” of the above document.

Let's assume that our installation has a MultiPlus II 5000VA connected to a battery and an AC coupled Fronius Primo 3.6 kW. Now let's apply the problem described in section 2.2 to this configuration. Let’s assume that on a sunny day you need to draw 4000 W from your system: 3.6 kW comes directly from the Fronius and 400 W from the battery through the MP2. Now let's assume that the battery is full and the load is suddenly cut off. The Fronius still delivers full power and the question is how fast the system regulates itself and where the power goes in the meantime.

I can understand that shutting down the Fronius takes time because it involves communication between the two systems: the MP2 has to change the frequency in response to the overload situation and the Fronius has to interpret it before shutting down. However, I find it hard to understand that the MP2 cannot cope with the overload situation because it is internal to the device and the electronics are supposed to react very quickly.

But suppose the MP2 is not fast enough to handle this situation properly, what does the Factor 1.0 rule change? There is no explanation in section 2.2 (or elsewhere in the document) as to why the PV power must be lower than the inverter power and how it fixes the problem.

I would appreciate if someone has an explanation as to why this rule solves the problem and why this factor needs to be 1.0 instead of 0.5 or 2.0?

drcoolzic asked
ludo commented ·

3 Answers

multiplus II 3000va avec installation PV 3,2Wp coupatible (vs règle du factor 1.0)


j'ai une installation de 8PV TrinaSolar de 405w, soit un total de 3240Wp (avec un onduleur Fronius primo 6.0-1 )

Je souhaite rajouter un système multiplus2 avec 2 batterie pylontech US3000c .

J'hesite entre un mutliplus2 48v/3000 ou 48v/5000 ? vu la différence de tarif et la puissance de batterie nécessaire pour le 5000, je me pose la question si peut partir sur une 48v/3000 ?

Si on suit la règle du factor 1.0, mes 3240 Wp est supérieur à la puissance du 3000v.

Mais y-a-t-il une marge de tolérance possible ? merci pour votre aide



damd22 asked
lalluyn answered ·

2 Answers

Is "Continuous Power" as specified in my Victron Manual the same as "Active Power"?

Is "Continuous Power" as specified in my Victron Manual the same as "Active Power", as in vs reactive power?

If not, how do I calculate the available ACTIVE power of my off-grid inverter?

Victron Easysolar 48/5000/70-100


michael-m-b asked
kevgermany commented ·

1 Answer

Phoenix 12/1200 underperforming in DC-AC-DC configuration

I have a camper van setup, with dual AGM vehicle batteries charged by high power alternators, and a separate house battery bank, which I also wish to charge from the vehicle alternators from time to time. I am trying to use a Phoenix 12/1200 to take the vehicle alternator power (Transit high power 250A dual alternator) to 120v to drive a Multiplus 12/3000 as "shore power" to charge the 4x100Ah Battleborn LiFePO house batteries. I was hoping for 7.5A of 120V from about 85A of DC input, but I cannot get anywhere close to that.

In testing, just driving a resistive electric convection heater, it will drive 500W, but in the 900W setting it goes into "overload" immediately. Even at 500W, it gets to thermal shutdown (two flashes on the red LED) after a couple of minutes - this with the inverter flat on the van floor in open space at 40F ambient.

In using the Phoenix to drive the Muiltiplus shore power 120V input, I can only get 3.5A x 120V reliably; at 4A x 120V the Phoenix goes into thermal shutdown after about 30 seconds, and at 7.5A it shuts down immediately in overload. I have of course verified that shore power from a household 15A or 30A outlet, or a campground 15A, drives the Multiplus just fine as expected.

Is the power factor of the Multiplus input so offset that the Phoenix is never going to work?

Why is the Phoenix going into thermal shutdown with a 500W resistive load (PF1.0, I assume)?

Is there a different model that might work to get me to the 7.5A x 120V lowest setting for the Multiplus charger input?

Does it help to use Multiplus "Dynamic Current Limit" and/or "Weak AC" settings?


neilhunt asked
neilhunt edited ·

2 Answers

High reactive power demand overloading inverter

hi Victronions,

I have the following setup: 3 x 15kVA Quattro inverters, 1 x Smartsolar MPPT and 1x Fronius 27kWp AC Coupled inverter.

The load is motors with a very high reactive power draw.

The total load is approx a total of 18kW over the three phases.

6000W phase A

6000W phase B

6000W phase C

The power factor of the load is very bad +/- (0.6)

i.e. a draw of

8000VAR phase A

8000VAR phase B

8000VAR phase C

Obvisouly the kVAR's is causing the inverters to overload.

Can a power factor correction unit be installed on the AC Output of the inverters?

What is best practice?

arjanbijker86 asked
michelg commented ·

2 Answers

Trying to size a Victron Phoenix for a bad power-factor load, how to proceed?

I'm trying to size a Victron Phoenix inverter to power a refrigerator. My power meter indicates it consumes around 700W peak (immediately after the compressor turns on, lasting less than 2s) then stabilizes at around 70W, *but* with a power factor of only 0.60.

I have two questions:

1) To what power should I size the inverter?

2) Would adding an appropriate capacitor in parallel to the compressor motor terminals (as explained here: https://youtu.be/qf_ZLIYT0Ro) allow me to use a smaller inverter?

Thanks in advance.

EDIT: just keeping everyone posted, I followed the instructions on the video above to calculate and add a capacitor in parallel to the refrigerator, and was able to correct its power factor from 0.60 to 0.98; as a consequence, the VA went way down and is practically identical to the Watts value now, and this made it much easier to size and buy my Victron inverter (and also allowed me to buy a much smaller one than I would have to). Thanks to everyone who contributed.

durval asked
durval edited ·

2 Answers

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