What are the modbus register values of the cerbo gx gui-v2 item DC Loads?
I think this item cames up after a firmware update of my PYTES V5 batteries.
Hint: The 625W shown in the screenshot are the power of the PYTES V5 heating pads.
That will only appear if you have enabled “has DC loads” in system settings.
It is a calculated value by the GX.
It means, only the local gui has access to this value
or
can I access via modbus to this value, or values like V and A and compute the power by myself?
And the PYTES V5 heating pads are a battery internal devices. How can the gx device “see” what happens inside the battery?
It is not a BMS CAN protocol information that is published to the gx device?
Do you have a shunt? If so what role is it configured to.
If you check settings → system is “has DC loads” enabled?
If so turn it off and the box will disappear.
This setting behaves like so (from the manual) :
Enable this for boats, vehicles and installations with DC loads and
chargers - in addition to Multi and MPPT chargers. This won’t
be applicable to most off-grid installations; and any discrepancy
between the DC current measured by the Multi, and by the BMV,
will be attributed to a 'DC system’.
As far as I am aware it cannot be sent via CAN, but can be provided by a shunt set in a DC load role.
No shunt.
Now I check the settings. Yes, if I disable the switch “Display DC Loads” the box disappears.
My idea was: Read the “DC Loads” value via modbus and show it in my Home Assistant Overview. So I never had to call the gui-v2 extra in the browser.
Now it fluctuates back and forth within a narrow range.
So this is only a DC current discrepancy value.
My cerbo gx’s power supply is connected to the Lynx. This load is also a part of the DC Loads value.
Normally, when you check the “Has DC System” option, the DC Load value is calculated automatically by the Cerbo. These calculations sometimes match reality, but sometimes they are completely wrong.
If you actually have DC-side loads and you care about accurate current consumption measurements, you need a dedicated SmartShunt connected to those loads and configured as “DC loads”. Only then will the values shown in this field be accurate.
Now, the system runs on battery, the DC Loads value is around 25W. This should be the power consumption of the cerbo gx device.
Could be the right value. 
But the main problem is, I cannot read this value via modbus. That’s a real shame.
You can calculate it yourself by subtracting the current (A) readings between the battery and inverter
, then multiplying by the bus Voltage for power.
Yes, I will inspect the relevant modbus registers. Then I’ll see what happens next. 
A little problem is the fast fluctuation of the current (A) values. The results from the modbus become very inaccurate. But the level (~50W or ~700W) gives me the information I want.
My problem of understanding is: Why is the inverter voltage higher than the battery voltage while discharging mode?
The battery voltage of the gui is the correct value; I checked this within the pytes software. Mhhhh, what meaning has the inverter voltage?
Checked the gui-v1…
The gui-v1 shows the same.
In the morning, the batteries reached my Minimal SOC of 30% and gone into state IDLE, the voltage difference remains.
Hi @MSl1
The Modbus register for DC Loads it’s register 860, DC System Power.
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Thanks!
I will check it.
Register 860 is only active if the “has DC system” option is enabled.
Glad that I could help. 
Now you can properly mark the solution for the initial question, in order to help others that are looking.
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