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carlos007 avatar image
carlos007 asked

Volts and hertz with Victron + pylontech

Hello. I'm new to the forum and I would like someone to help me with a question.


I have a Victron Quattro + Pylontech US2000C batteries. These batteries have a maximum charge voltage of 53.5 volts.


On the other hand, Victron says that the voltage at which the frequency starts to rise, in order to control an AC-coupled fronius inverter, is 54 volts.


The question is how can that system work, with these different tensions? it is impossible!!


Is there any way to modify the voltage at which the frequency rises, to adapt to the charging voltage of the pylontech batteries?


Thanks

frequency
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3 Answers
nickdb avatar image
nickdb answered ·

I suggest you open a free account at professional.victronenergy.com and follow the training.

Then carefully read the Fronius implementation docs.

https://www.victronenergy.com/live/ac_coupling:fronius

If this doesn't clear things up, you will have a better foundation for asking questions and receiving guidance.

There are many, many of these combinations in the field, it works just fine if you follow best practice.

No need to start adjusting settings if you aren't properly familiar with the ecosystem.

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carlos007 avatar image
carlos007 answered ·

Thanks for answering.


I have read and re-read everything the internet can offer me about it. And I have not found an answer to my question.

And yes, I am familiar with the system.


The problem is not from fronius, nor from victron.....but from pylontech, which has "low" charge voltages, in the US2000C model. Voltages impossible to modify.


The question is very specific, and the answer should be too.

Is it possible to modify the voltage at which Victron modifies the frequency, to reduce the power delivered by an AC coupled inverter?

If the answer is true, the question is how?


Thank you

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nickdb avatar image nickdb ♦♦ commented ·
Can you please provide a link to this information you are referring to.

If you follow the setup steps in the doc I linked to, for your use-case, it will work fine with any battery combination.

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carlos007 avatar image
carlos007 answered ·

https://www.victronenergy.com/live/assistants:pv-inverter-support#q1_the_system_is_locked_to_53_hz_and_does_not_resume


https://b2b.technosun.com/web/image/259084?unique=c0bdcd525e3ccf338ba5b2381bc4e571f0ced3e2


There you can see that the maximum charge voltage of the pylontech batteries is 53.5 volts.


And you can also see that the voltage from which the frequency increases is 54 volts.


In this case, it is impossible for it to work correctly, since when there is an excess of power, the charging voltage of the batteries will exceed the maximum.


Thank you

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nickdb avatar image nickdb ♦♦ commented ·
I think you may be misunderstanding this.

As I understand that, it is a secondary protection for overshoot, primary frequency control is determined by the battery settings.

Just follow the documented steps for battery configuration and the fronius. I think you’re creating a problem where there isn’t one.

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carlos007 avatar image carlos007 commented ·

3. Frequency control details

The Assistant will use the AC-output frequency to keep both the charge current and the charge voltage within limits.

To prevent DC and AC voltage overshoots because of varying solar irradiance and/or load fluctuations, it will limit the charge current already before battery voltage has rised up to the absorption voltage. It will derate the maximum charge current from 100% at 13.5 / 27 / 54V to 10% at 14.4 / 28.8 / 57.6V. These thresholds are not related to the configured absorption voltage.


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carlos007 avatar image carlos007 commented ·

Pylontech
1673357854375.png

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1673357854375.png (181.0 KiB)

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