Add total PV power sensor

[canton7]

Discussed in #128

^{Originally posted by andrewmooreio April 6, 2023}
Hi. I've just switched from the StealthChestnut integration and have noticed there is no total power sensor for PV output. e.g. current total solar generation PV1 + PV2 in W.

I've created a template sensor for now {{ (states('sensor.pv1_power') | float(default=0) + states('sensor.pv2_power') | float(default=0) ) * 1 }}, just wondering if it's possible to hard code it into the integration, as it's a really useful metric that I'm sure a lot of users would appreciate.

There may be other sensors that are provided by templates here, but the total PV power is a particularly useful one.

Cheers.

---

We probably need a new sensor type which adds two registers together?

[nathanmarlor]

Possibly extend the functionality you just added to combine multiple registers? I'm thinking something along the lines of a flag SUM, EXTEND?

[canton7]

Well it starts getting tricky -- what if we want to sum two 32-bit registers? They're separate concepts.

Another way would be to just create a template sensor ourselves and let HA handle things, but that feels needlessly wasteful...

[canton7]

I think a perfect solution might be a new sensor type which takes the two sensors to sum as inputs, rather than working directly on the registers? That way we don't have to worry about things like the two source sensors having different scales or post-processing steps, etc. They can just do their thing, and the summation sensor (which can even take an array of input sensors and apply a lambda to them) takes the results and combines them.

[canton7]

Looks like it shouldn't be too hard? async_track_state_change_event lets you subscribe to changes from multiple other entities. The integration sensor does a bunch of stuff we should be able to just copy

[ProtoxiDe22]

Does it make sense to also have a PV power total that sums the PV1 Power Total and PV2 power total values in KWh? i'm thinking having a single sensor in the energy dashboard would make sense especially if you want to do stuff with the forecast.solar estimates, working with a single value seems easier

[canton7]

The inverter provides that already, we call it "Solar Generation Total"

[ProtoxiDe22]

Damn i missed that, thank you.