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Michael Timler avatar image
Michael Timler asked

CCGX - DVCC -> How to Limit Charge Voltage using ModBus-TCP

I've noticed the addition in DVCC the ability to limit the managed battery charge voltage to a value of my liking. I am very happy, that this is finally possible now.
Now, I would like to set this maximum charge voltage using Home Assistant.

Inside my Modbus TCP services, I have access to com.victronenergy.systems.
According to CCGX-Modbus-TCP Register-list.xlsx, the only writing-enabled registers com.victronenergy.systems are the CCGX-relay-states.

Is there any possibility set the Maximum Charge Voltage per Modbus TCP from Home Assistant? If yes, what is the register of this service?

ESSCCGX Color ControlModbus TCPDVCC
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Michael Timler avatar image Michael Timler commented ·
Nobody out there?
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netrange avatar image netrange Michael Timler commented ·

https://www.victronenergy.com/support-and-downloads/technical-information ... There You get the modbus-tcp list ...

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mrhappy avatar image
mrhappy answered ·

Did you try this one?

chargelimit.png


chargelimit.png (80.7 KiB)
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shaneyake avatar image shaneyake commented ·
Address 2705 is charge current, 2710 is Limit Managed Voltage.
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Michael Timler avatar image Michael Timler commented ·

Thank you for this hint! The voltage solution works meanwhile perfect for me, but for my personal interest I will test, if one can work with limiting the current in a similar way.

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shaneyake avatar image
shaneyake answered ·

@Michael Timler It was just fixed, it was a read only register. It is now writable.
It will take sometime to reach the public release for GX firmware but it is in the works. Not too long now. It is address 2710 with a scale factor of 0.1V
https://github.com/victronenergy/venus/issues/849

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Michael Timler avatar image Michael Timler commented ·
Thanks, this answered the question!
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shaneyake avatar image shaneyake Michael Timler commented ·

Fix is now available. Firmware v2.80~17
https://community.victronenergy.com/questions/101754/venus-os-v28017-available-or-testing.html

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Michael Timler avatar image Michael Timler shaneyake commented ·

For those who are interested: I finally managed to write to adress 2710 with Home Assistant.

I use this to prevent my Pylontech US2000 stack to load to 100%. F.e a Maximum Charge Voltage of 51.4 V stops charging at around 95% BatterySOC.


Here an example to set the Maximum Charge Voltage using a slider type input_number

(https://www.home-assistant.io/integrations/input_number/)


First step:

Create an input_number helper.

Call it f.e. "Limit_Powerwall_Voltage_Helper", Min. 50, Max. 52,4, Step 0,1


Second step:

Create an Automation in config>automations


The automation should later show up in automations.yaml like this:


- id: '1645987579415' # Created by Automations GUI, can't do it by hand

alias: Limit Powerwall Voltage

description: Begrenzt die maximale Ladespannung des Victron MPPT-Verbundes

trigger:

- platform: state

entity_id: input_number.limit_powerwall_voltage_helper

condition: []

action:

- service: modbus.write_register

data:

address: 2710

unit: 100

hub: modbus_hub #depends on your defined modbus hub

value: '{ { states(''input_number.limit_powerwall_voltage_helper'') | float * 10 }}'

mode: single


READING WORKS LIKE THIS:

- name: "Limit Managed Battery Voltage"

data_type: uint16

unit_of_measurement: "V"

slave: 100

address: 2710

scale: 0.1

precision: 1

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lsgv avatar image lsgv Michael Timler commented ·
Just for my information why do you want to limit full charge to 95%? I also have Pylontech stack and am interested in understanding your reasoning. Thanks.
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Michael Timler avatar image Michael Timler lsgv commented ·

Just for lifetime reasons. If you hold a Lithium-Battery always on 100%, lifetime span will decrease significantly. For my stack is big enough to hold a 2 day current supply, during summertime my PV-system produces more than enough energy for my whole electricity consumption. There is no need to hold the whole possible battery capacity all the time.

Therefore I limit the max. charge limit to 80% during sunny periods.

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shaneyake avatar image shaneyake Michael Timler commented ·

Degradation at 100% SOC doesn't really happen with LFP batteries.
With most LFP battery systems it is actually better/even required to go to 100% most days to keep the cells balanced.

Pylontech US2000 is a lithium iron phosphate or LFP battery not NMC or other chemistries that suffer from 100% degradation. Just don't push the cells over 3.6V and they will be happy at 100%.

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Michael Timler avatar image Michael Timler shaneyake commented ·

Uuups, didn't know that, actually. Thanks for sharing that. In my particular battery, the Pylontechs are a mixture from US2000 and 3000 from different building dates.

The stack is running on 80% since months now, however, have not watched any degradiation which could come from unbalancing.

Will measure that now using the Pylontech software, because the master-slave-system does not work properly in such a constellation. (You can not get US 3000 and 2000 from different years to work in one master-slave stack, no matter, if you use their Hub or try other constellations. Have a good compromise working here, but can't get the data correct for Victron CCGX. However, that's an other tale....)

From reading, this article

https://www.torquenews.com/15475/battery-charging-behavior-tesla-recommends-charging-lfp-models-100-key-voltage-0

I have understood your point more clearly now.

Interesting point, thank you very much for that hint.

Michael


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Michael Timler avatar image Michael Timler shaneyake commented ·

Thank you very much for this hint! I actually could monitor Pylontechs in several PV arrangements meanwhile and have established a new way to set the voltage limits in order to not override the 3.6V per Cell at my customers systems while charging. Really great improvement, thank you very much.

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