question

jacola avatar image
jacola asked

Advice with ESS system, external control and phase balancing

Hello, i am new on this forum. Professional experience with Modbus/TCP, comms, energy, MQTT and all relevant technologies but new with Victron.

Yesterday my installer finished a larger ESS system for my farm (16 pylontech batteries, 3x multiplus 5000, i have 3 solar production systems of total about 15kw, plus many consumption points to control).
MY ET340 is hundreds of meters from the battery installation (this is a quinta), so i cannot really run RS485. But for fine grain control i rather want to use the ESS system "semi dumb" anyway in that i can just use it as a great battery management system and fine tune/control the carging/discharging of the battery by MQTT or Modbus/TCP.

I see there is Modbus/TCP but the amount of writeable registers is rather small ... and i cannot see how i can command the multiplus inverters separately to draw or produce a certain amount of power (to both use the batteries efficiently as well as to do phase balancing).

Can someone help me with those ?

Johannes


MultiPlus Quattro Inverter ChargerESS
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2 Answers
jacola avatar image
jacola answered ·

OK :) sorry for bothering. I found some of the answers. Easiest via MQTT, i can control the multiplusses per phase with commandline tools already:

mosquitto_pub -h 192.168.66.8 -t "W/0xxxxxxxxxxxx/vebus/261/

Hub4/L2/AcPowerSetpoint" -m '{"value": -4000}'

But now i still have to ask, with no meter being connected, can i provide the actual measurement data also via MQTT writes ?

Cheers
Johannes


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dayandnight avatar image
dayandnight answered ·

Hello @jacola,

what I think I got from your thread is, that there is an energy meter ET340 installed but it is to fare away that it would work? Was the communication between the ET340 and the GX-device tested? What GX device do you have? Cerbo GX? Color Control GX? GX??

In case your PV system is grid based and for doing any phase compensation it is essentially to have a grid meter, because the "controlling unit" needs to know how much energy is on the way in the system and in which direction? Based on my understanding what you wrote it is now only necessary to find a way for a long distance communication between the ET340 and your GX device. In case it is really not possible to do it by copper wire it will be possible by radio with Victrons Zigbee device, data sheet spec is speaking of 1.600m distance in open field. If you really want to control the ESS system on your own, you can do it in mode 2 or 3 but for the beginning it is much easier to do first ESS experience in mode 1 and you will need anyway a communication to the energy meter.

Success!

DayAndNight

3 comments
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jacola avatar image jacola commented ·

Hi DayAndNight, i got the control of the ESS working, it is actually working really well. i can read the meter about 5 times per second on a local controller and do the setpoint corrections for the ESS, but .. if i have a heavy load switch (pumps or heater with 5kw consumption jump on) the response of the ESS/multipluses is still quite slow, resulting in few seconds consumption from the grid worst case. I assume that is owed to the principle of operation of the multiplus, but i will see to get at least smaller load changes balanced out with split second accuracy.
Cheers

johannes


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wasolar avatar image wasolar jacola commented ·
Hello @jacola ,

is it possible to share your solution to control the ESS?

Thanks and regards
Flo

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jacola avatar image jacola wasolar commented ·
Hi, in the meantime, a lot happened.

For maximum stability, i switch my ESS to 'off-grid' during the day, and it works really well that way. During 8 months, i can usually get through the night with my batteries so it happens that for some days or even weeks if the weather allows, i do not go on-grid.
When on-grid, i use the scheduled charge function to charge the battery up.
Going to control the 'when' and 'how much' to charge via modbus/tcp in the next days. So far, i just change the charge limit and the on/off grid (via modbus/tcp) plus i read out all relevant data in a few seconds interval and save it to a victoriametrics/grafana cloud solution.

My recommendation: use ESS mode 2, not 3. Mode 3, is never going to be very accurate. It took me some effort to rewire all (to get ESS 'in the path' from public grid to the installation), but it solved all problems i had before.

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