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tobyfw avatar image
tobyfw asked

External Control - logging and understanding

Dear community. There is a lot of "External Control" going on in my Victron system. The MP2 seems to be controlled by the Pylontech batteries, the MPPTs by the MP2, Cerbo or batteries or all three. Sometimes MPPTs switch off during the day, and I can only guess, why. Is there a log of external control messages, who controls what how and for which reason? Thank you

ESSMPPT SmartSolarPylontechexternal control
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1 Answer
nickdb avatar image
nickdb answered ·

You probably need to brush up a bit on how ESS works, the manuals and video training are quite thorough.

With a managed battery, the system is exclusively under control from the battery. Devices will permanently be under external control as long as the battery is connected.

Impossible to tell why chargers are powering down, could be many reasons but there is very little to go on in your post, so suggest you properly document your environment, any changes and support it with charts that show what is going on in the various areas.

First is to make sure your config is right from the setup doc:

https://www.victronenergy.com/live/battery_compatibility:pylontech_phantom

Ultimately everything is voltage controlled, so that is where you have to look.

The exception being ESS and SOC, some people make the mistake of setting optimised mode and 100% minimum SOC, which is not a good thing to do, and will power off chargers when the batteries are full, ignoring loads.

Posting may be challenging as forum uploads are broken, so rather try the new community site, detailed on the modifications section announcement.


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tobyfw avatar image tobyfw commented ·

Thank you. I intentionally left out details, as my question was not really about any specific issues, but on the existence or absence of a logging mechanism for external control. Yes, I can also guess what happens by looking at all the parameters, but I wonder how such a central mechanism would be implemented without proper logging mechanism. Can it really be, that when Pylontech BMS tells the MP2 or the MPPTs to change their behavior, this important event is not logged anywhere in the system for further analysis? At least in some CAN-Bus log on the GX?

Also: I somewhat figured that the battery has full control, but is the algorithm explained anywhere, or is it a "black box", which can only be guessed by observation? It is not in the Pylontech manual for sure. For example: Battery is full, and MP2 is reaching its inverting limits. Some MPPTs need to be shut down or limited. But how is the MPPT for limitation chosen, when does it start, and which form does it take? (only on/off, or gradually decreasing charging rate?) etc. Can you recommend a document which would spell this out?


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