Measuring Energy in Home Batteries

[rjdalga]

Feedback

Note: The Shelly EM with CT's only measures alternating current (AC), NOT direct current (DC) which batteries generate. Furthermore, solar panels output DC current which can then be pushed directly through to the batteries (via a charge controller).

URL

https://www.home-assistant.io/docs/energy/battery/

Version

2023.9.3

Additional information

No response

[reedy]

I notice the page doesn't mention DC or AC at all, nor where the measurement is done.

These documentation seem definitely to be based on the fact (without stating it), that you're measuring on the AC side of the inverter/charge controller (which could be separate or different devices).

19330 seems to document this, duplicated against https://github.com/home-assistant/core/issues/55974

https://www.home-assistant.io/docs/energy/solar-panels/ seems to have the same flaws in wording/documentation

https://community.home-assistant.io/t/best-way-to-monitor-dc-voltage-from-solar-array-and-battery-bank/355739/19 and othes have solutions on how to monitor DC...

[rjdalga]

That is correct; however not all solar systems are designed the same. For example, Generac's PWRcell system (i.e. inverter and batteries) takes the DC output of the PV array and sends it directly thru the inverter to the batteries until fully charged. Any excess energy from the PV array is inverted to AC to supply the home (or exported to the grid). Although Generac has a well designed API to monitor their systems via a cell phone, there is no HA integration as of yet. The only workaround that I can see is to use a Victron shunt on the DC battery side of these types of systems (although I have not purchased one yet) or to scrape the Generac website directly.

On Mon, Oct 9, 2023 at 4:06 PM Sam Reed @.***> wrote:

I notice the page doesn't mention DC or AC at all, nor where the measurement is done.

These documentation seem definitely to be based on the fact (without stating it), that you're measuring on the AC side of the inverter/charge controller (which could be separate or different devices).

19330 https://github.com/home-assistant/home-assistant.io/issues/19330

seems to document this, duplicated against #55974

https://www.home-assistant.io/docs/energy/solar-panels/ seems to have the same flaws in wording/documentation

https://community.home-assistant.io/t/best-way-to-monitor-dc-voltage-from-solar-array-and-battery-bank/355739/19 and othes have solutions on how to monitor DC...

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