aWATTar binding: Beta and discussion

[masipila (Markus Sipilä)]

@Doug_Culnane

Currency exchange rate is tricky as this is dynamic. I would not add this to the scope of the binding. I would hope the prices are supplied in the local currency. If not then it is the job of another binding to get the currency rate (or an http binding get)… and a rule to calculate the local cost… that is how i would try to solve it.

Your hope is unfortunately not a safe assumption. Entso-E API returns the spot prices in EUR/MWh, just like the aWATTar API does.

@Wolfgang1966 or anyone else: Is it possible to update Thing configuration parameters programmatically from a Rule? I believe the easiest way to solve the currency exchange rate would be that the users of non-EUR currency would be responsible for fetching the current exchange rate by one way or another and storing that to an Item. Then they could have a Rule that when that Item changes, the new value is updated to our Thing configuration.

I actually need this capability (or similar that produces the same result) to be able to fulfill my current use cases which I mentioned in a couple of comments above.

@Doug_Culnane you might enjoy reading my current solution: Control a water heater and ground source heat pump based on cheap hours of spot priced electricity - #13 by masipila

I charge our electric vehicle so that I have one Item called “CarChargingHours” which I can manually update with a stepper widget. The cheapest consequtive slot is then calculated so that the end time is next morning at 6:00. The “how many hours will I need” math is very easy to count as 10% of battery is reasonably close to 1h so if the battery level is for example 40% and I want to charge it to 80% I would allow 4 hours.

Cheers,
Markus