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Josep morancho avatar image
Josep morancho asked

MPPT RS & PV power

I am going to upgrade my pff-grid system as I will need more power for my heat/cold pump.

Of course this will affect PV production, battery capaxity and inverter power.

On the PV production side I am thinking to use a MPPT RS 200A charger and I have a doubt.

According to tech specs, the mppt rs 200A charger has 4 tracker and every one of them can support a maximum of 7,2Wp. This means that if all 4 trackers have the maximum PV power connected, the total input power would be 28,8Wp. On the other side the maximum charge capacity output is limited to 11,52W.

I want to understand that MPPT RS will limit input power from the PV to match with the maximum output power of 11,52W

Am I right?

I also want to undestand that PV input is oversized to allow to get maximum 200A charge in winter when PV production decreases. Correct?

Thanks




mppt rs
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3 Answers
nickdb avatar image
nickdb answered ·

It is best to use the MPPT calculator to verify any config.

Rule of thumb for over panelling is 30% beyond that it has diminishing returns, but ultimately you need to be within Voc and Isc limits, and the 8x float V restriction.



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Josep morancho avatar image
Josep morancho answered ·

I do not know the 8xVfloat restriction. Why 8 or not 7x or 9x? Where is this restriction documented?

Thanks

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nickdb avatar image nickdb ♦♦ commented ·
Its in the datasheet specs
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Matthias Lange - DE avatar image
Matthias Lange - DE answered ·

It's in the datasheet (footnote 1) and the manual.

https://www.victronenergy.com/media/pg/SmartSolar_MPPT_RS/en/installation.html#UUID-a96ec91b-a21c-0536-1a40-278fd7f9410d

It's a hardware limitation due to an internal transformer with a fixed ratio of 8:1.

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Josep morancho avatar image Josep morancho commented ·

Apologies. I had not read the footnotes.

By the way, the mppt excel calculator does not support yet the MPPT RS 200A. Only the 100A.

Do you know if it will be updated?

Thanks

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Josep morancho avatar image Josep morancho Josep morancho commented ·

I have seen that a new mppt tool was releses today. I tested and works quite well

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