# Victron / PV converter: available power ???

Forum solar photovoltaic PV and solar electricity generation from direct radiation solar energy.
dedeleco
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Forhorse wrote:Since I = U / R or (I = U / Z in alternative)
You will explain to me how with R (or Z) fixed, you manage to reduce I by keeping U constant ...

answer given to Forhorse who forgets to specify which R or Z he is talking about, because it all depends on the point of view, use or intelligent generator:

Forhorse, without explaining it, has a completely different model from that of Remundo, in fact.
He thinks a device of use requiring too much current with its resistance too weak and fixed, which prevents such a limitation, which breaks down by safety shutdown, the generator.
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Forhorse
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I'm talking about R or Z of the receiver ... in this subject it is a question of supplying an electrical resistance, no?
the internal impedance of the inverter who cares a little at the base (and since anyway the output voltage is regulated, it is normally negligible)
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Remundo
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Forhorse, Dede gave you some ideas.

You can continue to search, for example for the maximum transfer of power it is necessary to adapt the impedances between a generator and a linear load ...

And when the generator is not linear (example PV panel + variable sunshine), it is even more complicated to find the point of maximum power ... There are internal MPPT algorithms which make i and u evolve by trial and error successive and observe whether the power is improved or not. They must also respect the voltage / current ranges ...
Forhorse wrote:Since I = U / R or (I = U / Z in alternative)
You will explain to me how with R (or Z) fixed, you manage to reduce I by keeping U constant ...

Precisely, U is not constant ...

We call that a solar charge controller in isolated site. Example the Steca Solarix

Any off-grid inverter is a charge regulator, even more complex if it converts from DC to AC 220V ...

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Forhorse
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Remundo wrote:Precisely, U is not constant ...

It takes me for an idiot ... It's not you who said 5 posts above:
Remundo wrote:
Because it can also be content to limit its current to maintain its tension.

Remundo wrote:We call that a solar charge controller in isolated site. Example the Steca Solarix

Any off-grid inverter is a charge regulator, even more complex if it converts from DC to AC 220V ...

A charge regulator and an inverter are two totally different devices that do not have the same function at all.
We are talking about a off-grid inverter
There's no point in trying to do pirouettes to try to be right.
An off-grid inverter, commonly known as a voltage converter, simply transforms a low voltage DC into 230V / 50HZ
Il does not integrate an MPPT algorithm et don't lower her blood pressure to adapt to an overload that would be longer than a current draw.
If the connected load requires more current than it can supply, it goes into safety mode.
If the DC voltage source to which it is connected cannot provide the power that it itself must provide, and this voltage therefore drops, it also goes into safety.

The work of a solar charge regulator, even MPPT, is quite different and it was not mentioned in the original question of the subject, nor even in the debate which followed to know if an inverter of less than 2000VA could supply power. a load of 2000VA

And even somewhat hybrid devices like the sunny island SMA which integrate charge regulator, inverter and charger, do not have this behavior.
In stand-alone mode, either it can provide the requested power and maintain the voltage, or it cannot be cut.

It's a bit normal, it's a bit like ErDF saying, "well, the network is temporarily overloaded, you all go to 110V for a few minutes" ... I can't imagine the damage!
So I do not see why an inverter, supposed to replace the network, would have this behavior ...
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Remundo
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I gave you a possible operating scenario ...

Moreover, "maintaining your voltage" does not mean respecting it to the nearest mV, but maintaining it within an acceptable range. The EDF vacuum sockets are commonly between 215 and 240V efficient ...

And under load, there may be more than 10V ohmic drop, especially if it's pulling hard.

Inverters, whether injection or isolated, make the best possible balance between their load and their source; in principle, they seek an optimum.

You are as stubborn as a blackberry ... does this have to do with your avatar?

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Remundo
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Forhorse wrote:It's a bit normal, it's a bit like ErDF saying, "well, the network is temporarily overloaded, you all go to 110V for a few minutes" ... I can't imagine the damage!
So I do not see why an inverter, supposed to replace the network, would have this behavior ...

ErDF is effectively subjected to voltage variations.

But it is essentially the frequency of the network which is the sign of the instantaneous power mismatch between the total load and the sources.

If f> 50 Hz, then the rotating generators are racing, sign of an insufficient load
If f <50 Hz, then the rotating generators slow down, sign of an overload
If f = 50 Hz, it is the sign of the perfect equilibrium of the network.

On the isolated MPPT site, this link explains in simple words:
http://www.energiedouce.com/conseils-fa ... eurs-mppt/

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Forhorse
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Well, listen, if you can't tell the difference between a battery charge regulator (which doesn't necessarily include an MPPT) and an inverter, unfortunately I can't do anything for you.

Start by installing this kind of equipment in your home, and we'll talk about it ...
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Remundo
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Thanks, I have already installed quite a few kWp.

I repeat that isolated inverters have an MPP. This topic deals with charging an off-site inverter on a heating resistor.

This inverter works from PV panels and batteries. It therefore necessarily has an MPPT.

As no one here knows the MPPT management electronics / algorithm of this inverter, only experience can answer the question "does this inverter support being connected to resistance or not?"

I found some answers (unfortunately not precise enough) on the Victron Phoenix C24 / 2000 off grid inverter proposed by Chris:, see in this brochure page 27
Here are the reasons for disconnection:
4) Protection
a) Short circuit at output
c) Battery voltage too high
d) Battery voltage too low
e) Temperature too high
f) 230 V AC on converter output
g) Input voltage ripple too high

This isolated inverter can also withstand peak power up to 4000 W ...

Very smart the one who knows how long the 2000 W of the resistance are supported ...

Personally, I think it can withstand resistance for a few seconds, the rest is unknown.

For safe operation, it would be necessary to upgrade to the 3000 model (2500 W nominal).
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dedeleco
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Totally agree with Remundo !!
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Forhorse
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Remundo wrote:I repeat that isolated inverters have an MPP. This topic deals with charging an off-site inverter on a heating resistor.

Go give me some references
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