[Bug]: Why only exporting in the hour with the lowest price

[SimonYoungtree]

Contact Details

siempoot@gmail.com

VRM / Site iD

287956

Country / region

Netherlands (nl)

B max

40

TB max

6

FB max

6

TG max

10

FG max

10

Battery costs

0.04

Buy price

(p+0.02+0.13)*1.21

Sell price

(p-0.02)*1.21

feed-in possible

yes

feed-in possible

None

What happened?

Yesterday between 14:00 and 15:00 the price was at its lowest (+/- p=-0.02). Only during that particular hour the system decided to export

Relevant log output

No response

Screenshots

![DESCRIPTION](LINK.png)

[SimonYoungtree]

Turned Dyn-ESS off for now.

[PoolsideKelbi]

Hey @SimonYoungtree, thanks for reporting.

The response to this issue is the same as this, hence the fix is underway :).

In more detail, the issue here is that for the hour 14 the algorithm planned to charge the battery by 0.44 (which was the excess PV yield after consumption according to the forecasts at that hour). Since there is an internal process that makes the battery usage conservative (essentially only allows charging/discharging if the planned charge/discharge amount is above 10% of the maximum charge/discharge), the battery was set to be idle. We are planning to change how this conservative treatment is handled. However, this by itself is not the sole cause of this odd behaviour.

As it can be seen from your screenshots, the forecasts were off: there was 3.3 kWh excess PV yield. And since the battery was idle, all the excess ended up going to grid. It is important to note that the inaccuracies caused by forecasts will create situations that in hindsight could be handled better. And sadly, due to the nature of forecasting, there will always be some inaccuracies present. Thus, per hour Dynamic ESS might not always make optimised decisions, but over a longer period of time its planning promises for less costs made on the battery/grid.

I hope this satisfies your curiosity with regards to Dynamic ESS's decision-making :)

[SimonYoungtree]

Hi Ali,

Thanks for your answer.

I will continue testing as soon as there is any version update.

And I will provide feedback. If it is useful to you I can turn it on anyway. Let me now.

Greetings, Simon.

Op do 3 aug. 2023 12:30 schreef Ali Kalbiyev @.***>:

Hey @SimonYoungtree https://github.com/SimonYoungtree, thanks for reporting.

The response to this issue is the same as this https://github.com/victronenergy/dynamic-ess/issues/35#issuecomment-1658269242, hence the fix is underway :).

In more detail, the issue here is that for the hour 14 the algorithm planned to charge the battery by 0.44 (which was the excess PV yield after consumption according to the forecasts at that hour). Since there is an internal process that makes the battery usage conservative (essentially only allows charging/discharging if the planned charge/discharge amount is above 10% of the maximum charge/discharge), the battery was set to be idle. We are planning to change how this conservative treatment is handled. However, this by itself is not the sole cause of this odd behaviour.

As it can be seen from your screenshots, the forecasts were off: there was 3.3 kWh excess PV yield. And since the battery was idle, all the excess ended up going to grid. It is important to note that the inaccuracies caused by forecasts will create situations that in hindsight could be handled better. And sadly, due to the nature of forecasting, there will always be some inaccuracies present. Thus, per hour Dynamic ESS might not always make optimised decisions, but over a longer period of time its planning promises for less costs made on the battery/grid.

I hope this satisfies your curiosity with regards to Dynamic ESS's decision-making :)

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