[Request] Add calculated output (battery) power & efficiency to mqtt

[alexz707]

Is your feature request related to a problem? Please describe.

I want to work (calc SOC) with the ouput power of the victron because I don't have access to my BMS.
Ofc I could calculate the power in HA but as the value gets already calculated on openDTU I thought it would be nice to also publish that value(s) over mqtt.

Describe the solution you'd like

Publish calculated battery power and efficiency over mqtt

Describe alternatives you've considered

Calcualte it in home assistant.

Additional context

BTW: Great work! appreciate it! :)

[schlimmchen]

Please specify in more detail what you want. What value in what unit should be published to what topic?

[spcqike]

if i understand correctly he wants to calculate the SoC in HA based on victron charging power and hoymiles discharge power.

this would be possible in firmware, too. but i see several disadvantages as the systems only query the data once in a while. for static discharging, that wont be a problem. but IMO the charging current wont be reported frequent enough to get reliable SoC values.

smartshunts and BMS have dedicated ICs that only monitor current/voltage/power and calculate energyflow and SoC based on that, with several measurements and updates per second.

@alexz707 i guess your best (or more reliable) option would be a dedicated smartshunt, either a victron original or a DIY one

[schlimmchen]

if i understand correctly he wants to calculate the SoC in HA based on victron charging power and hoymiles discharge power.

IMHO that's futile and a waste of time.

Still, I think it's valid wanting the MPPT charging power to be available through MQTT, if that's what is asked. For that reason I wanted a list that specifies what is wanted, regardless of whether or not it makes sense do to the calculations that we are talking about.

[swingstate]

my 2cents, using a dedicated shunt is much more convenient and integration into HA is very simple with an ESP/ESPhome and https://github.com/KinDR007/VictronMPPT-ESPHOME. I'D recommend taking that route.

However, @schlimmchen enabling onBattery to receive the SOC information that HA has available (through whatever integration, MPPT-ESPHome is just one example) through MQTT would be nice, as long as onBattery can use that information similar to the Pylontech CAN SOC readings.

[ele-dev]

Yes I would also very much appreciate a feature for openDTU on Battery to fetch SOC values over mqtt or http from any external source. In my special situation: I actually have a Pylontech Battery but for some reason that can't be explained, it's not sending out these valueable information from the internal BMS over the CAN port like it should and therefore I am not able to discharge the battery based on the actual SOC.
For all custom battery setups with other BMS than Pylontech it would be a very useful feature too if they could feed the SOC somehow into open dtu on Battery. For example over MQTT and ESPHome

[schlimmchen]

See #293 (MQTT as Battery Data Provider).

[alexz707]

Sorry for the late reply, I was on vacation :)

I was already thinking of buying a smart shunt for this but I was waiting on the JK BMS branch to be merged to have a look at it. I will use 2 BMS for 2 batteries in parallel so I'm not sure if openDTU can handle 2 jk bms's.

Currently with 1 battery I'm calculating the SOC in HA myself with the voltage and current values published by openDTU from the victron data. I saw that the power is already displayed in the GUI. So I thought it would be a good idea to just publish the output power as it is already calculated and I wouldn't need to do that in HA.
I know it's not accurate but since it is in the UI it why not just publish that value?

I would like to avoid to have severall esps running just for the battery, I would prefer to only have one esp which does everything. That's also a point which kept me from buying the smartshunt.

Is it already possible to get the data of a connected smart shunt out of the victron mppt directly?

[schlimmchen]

I'm not sure if openDTU can handle 2 jk bms's

Nope.

since it is in the UI it why not just publish that value?

Yup, that's doable and easy.

Is it already possible to get the data of a connected smart shunt out of the victron mppt directly?

No, but see #452: You can connect to a SmartShunt directly using a separate serial connection.

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