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wolfandy avatar image
wolfandy asked

MPPT and Pylontech - do I need a BMV?

Hi all

I am currently running a non-Victron integrated MPPT/inverter together with 2x 3.5kWh Pylontechs and 9 panels. I have a Raspberry Pi solution in place that connects both to the inverter and the Pylon BMS and controls the inverter modes according to the BMS SOC (rather than voltage reading).

As the built-in MPPT is of older generation, I am now contemplating adding a Victron MPPT 250/85 to the system and moving my panels (and using my current unit purely as inverter).

What I do not fully understand yet is if I need to establish some form of communication between the Pylon BMS and the Victron MPPT? I've read about VE.Smart Networking but do not understand what the benefit of adding a BMV (or SmartSense) would be.

Can anyone here please help me understand?

Thanks in advance

MPPT ControllersPylontechVE.Smart Network
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1 Answer
JohnC avatar image
JohnC answered ·

Hi @wolfandy

There's a little about interfacing Pylon here: https://www.victronenergy.com/live/battery_compatibility:pylontech_phantom

This is sorta all Victron can 'support'.

What you'll need is a GX box, a number of varieties available. Or even indeed an rPi, which can handle the open-source Venus OS firmware.

So no, you don't need a BMV or any Smart kit.

The trouble is Victron have parallel types of systems, each with a purpose, and you need to select which from the confusion. Then add in the options you want.

The GX is the premium end, but give it some www, and the free VRM portal, and you'll likely want more of that..

Keep researching until you know enough to justify the spend on anything. You're doing that already of course, keep it up.

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wolfandy avatar image wolfandy commented ·

Thanks for the feedback, @JohnC

But I still do not fully understand the benefit of having the MPPT and the Pylon communicate (via GX or any other system). What is the benefit? What information actually gets passed between them? How is it better than setting the charging voltages on the MPPT initially via Bluetooth app and then having it measure the battery voltage at its terminal (cable between MPPT and Pylon will be less than 1m)? How would knowing the SOC from the Pylon BMS change the MPPT behaviour compared to standard voltage measurement? I don't need to worry about the Pylon's temperature as I live in a place where it never freezes...

I understand that knowing the BMS SOC will allow an inverter to more accurately switch between battery and grid mode (rather than voltage which might not accurately represent the actual SOC due to sudden drops from higher loads being switched on). But I do not understand if a similar advantage exists for the MPPT.

The other challenge is that I will not be able to also connect a GX to the Pylon as the Pylon's CAN port is already used for the connection to my rPi controlling the inverter. The software currently running on the rPi is also capable of reading performance data from the Victron MPPT and post it to Emoncms. If I ever go fully Victron and also replace the inverter, then I understand that a GX will be required to run ESS.

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