Automatic evcc batteryGridChargeLimit and smartCostLimit adjustment / Automatisches und günstiges Netzladen

[ThinkEV]

For english translation: see next post

Hallo Leute,

das Netzladen der Hausbatterie kann durch evcc geregelt werden. Dafür kann man eine Ladeschwelle in evcc einstellen. Da sich die Strompreise bei dynamischen Stromtarifen täglich ändern, müsste man diese Schwelle ebenfalls täglich anpassen. Das erledigt das hier vorgestellte Skript automatisch.

Im Winter reicht der Ertrag einer PV-Anlage oft nicht aus, um den Hausakku tagsüber wieder voll aufzuladen. Mit dieser Automatik kann man den Hausakku in der Nacht zu den günstigsten Stunden nachladen.

Voraussetzungen:

• dynamischer Stromtarif (tibber, awattar, ...)
• Hausakku mit aktiver Batteriesteuerung und Lademöglichkeit vom Netz
• ggf. Freischaltung vom Hersteller erforderlich (z.B. bei Tesla Powerwall)
• jq (sudo apt-get install jq)

Manuelle Aktivierung in evcc ausprobieren:
Darstellung > Experimentell > Experimentelle Funktionen anzeigen -- aktivieren
Hausbatterie > Netzladen > Preisgrenze -- einstellen

Sobald das einmal manuell aktiviert wurde, kann man die Preisgrenze täglich über mein hier veröffentlichtes Skript per Cronjob anpassen lassen. Das Skript läd die Tarifpreise vom Netz (grid), sortiert diese nach dem Preis und erlaubt die $HOURS günstigsten Stunden.

---

Beispiel von heute mit HOURS=3:

0.2318
0.2404
0.2408 <-- dieser Wert wird eingestellt
0.2462
0.2557
[...]
0.2864
0.3128

Da die neuen Tibber-Preise täglich um ca. 13 Uhr veröffentlicht werden, schlage ich den Cronjob-Aufruf um 13:30 Uhr vor:

# m h  dom mon dow   command
30 13 * * * /home/USERNAME/evcc-auto-batterygridchargelimit.sh >/dev/null

Es wird daneben keine externe Steuererung benötigt (Netzero App).

Das Skript: evcc-auto-batterygridchargelimit.sh.txt

#!/bin/bash
# ===== evcc-auto-batterygridchargelimit.sh =====
#
# Feel free to modify and improve this script!
#
# Please give feedback at:
# https://github.com/evcc-io/evcc/discussions/17302
#

# ---------- settings ----------
# Address of your evcc:
# EVCC="http://evcc:80"
EVCC="http://evcc:80"

# allow the cheapest hours of the day:
#HOURS=3
HOURS=3
# ------------------------------

CURRENTVALUE=$( curl -X GET "$EVCC/api/state" 2>/dev/null | jq | grep batteryGridChargeLimit | cut -d : -f 2 | cut -d , -f 1 )
echo -n "batteryGridChargeLimit:$CURRENTVALUE -> "

# get tariff for grid
TARGETVALUE=$( curl -X GET "$EVCC/api/tariff/grid" 2>/dev/null | jq | grep price | tail -n 34 | cut -d : -f 2 | sed -e "s/^ //" | sort -n | head -n $HOURS | tail -n 1 )

curl -X POST "$EVCC/api/batterygridchargelimit/$TARGETVALUE" 2> /dev/null | cut -d : -f 2 | cut -d "}" -f 1

Tesla Powerwall-Nutzer stellen in der Tesla App bitte ein:
Betriebsmodus: Eigenversorger
Netzaufladung: Ja
Stromtarif ist egal.

Welche Einstellung für $HOURS soll ich wählen? Das muss man ausprobieren. Ich vermute 2-3 Stunden täglich können reichen.

Fügen Sie am Ende des Skripts die folgenden Zeilen hinzu:

CURRENTVALUE=$( curl -X GET "$EVCC/api/state" 2>/dev/null | jq | grep smartCostLimit | cut -d : -f 2 | cut -d , -f 1 )
echo -n "smartCostLimit:$CURRENTVALUE -> "
curl -X POST "$EVCC/api/smartcostlimit/$TARGETVALUE" 2> /dev/null | cut -d : -f 2 | cut -d "}" -f 1

Dadurch wird auch der Wert von smartCostLimit auf dieselbe Einstellung aktualisiert.

Unterhalb dieses Schwellenwerts wird automatisch mit dem Laden begonnen! Auch sehr schön!

[ThinkEV]

Hello!

The mains charging of the house battery can be regulated by evcc. To do this, you can set a charging threshold in evcc. Since electricity prices change daily with dynamic electricity tariffs, this threshold would also have to be adjusted daily. The script presented here does this automatically.

In winter, the yield from a PV system is often not enough to fully recharge the house battery during the day. With this automatic function, you can recharge the house battery at night at the cheapest hours.

Requirements:

• dynamic electricity tariff (tibber, awattar, ...)
• home battery with active battery control and charging option from the grid
• activation from the manufacturer may be required (e.g. with Tesla Powerwall)
• jq (sudo apt-get install jq)

Try manual activation in evcc:
Display > Experimental > Show experimental functions -- activate
Home battery > Grid charging > Price limit -- set

Once this has been manually activated, the price limit can be adjusted daily using my script published here via cron job. The script loads the tariff prices from the grid, sorts them by price and allows the $HOURS cheapest hours.

---

Example from today with HOURS=3:

0.2318
0.2404
0.2408 <-- this value is set
0.2462
0.2557
[...]
0.2864
0.3128

Since the new Tibber prices are published daily at around 1 p.m., I suggest calling the cron job at 1:30 p.m.:

# m h dom mon dow command
30 13 * * * /home/USERNAME/evcc-auto-batterygridchargelimit.sh >/dev/null

No external control is required (Netzero app).

The script: evcc-auto-batterygridchargelimit.sh.txt

(for the script in plain text: see previous post)

Tesla Powerwall users please set in the Tesla app:
Operating mode: Self-supply
Grid charging: Yes
Electricity tariff does not matter.

Which setting for $HOURS should I choose? You have to try it out. I suspect 2-3 hours a day will be enough.

At the end of the script, add the following lines:

CURRENTVALUE=$( curl -X GET "$EVCC/api/state" 2>/dev/null | jq | grep smartCostLimit | cut -d : -f 2 | cut -d , -f 1 )
echo -n "smartCostLimit:$CURRENTVALUE -> "
curl -X POST "$EVCC/api/smartcostlimit/$TARGETVALUE" 2> /dev/null | cut -d : -f 2 | cut -d "}" -f 1

This will also update the value of smartCostLimit to the same setting.

Below this threshold, charging will start automatically! Also very nice!

[GrimmiMeloni]

Thanks for sharing. Suggestion for optimization. You can toss out all the cut and greps and make things more robust, by simply using the jq internal json processing. As an example:

jq .result.batteryGridChargeActive

[ThinkEV]

How do I do all that with just jq?
curl -s -X GET "http://evcc:80/api/tariff/grid" | jq '.result.rates [].price' | tail -n 34 | sort -n | head -n $HOURS | tail -n 1 )

[GrimmiMeloni]

Haha.. 😅 .... did not see this one. I guess the answer is - you don't.

I was more looking at things like

jq | grep batteryGridChargeLimit | cut -d : -f 2 | cut -d , -f 1

It was mostly the combination of jq and grepping for a JSON property that caught my eye. Maybe you also still need the cuts from the example above? I cannot really reproduce your input, as I do not have the grid charging setup, and hence my local /api/state result does not have the fields you are processing. So I cannot be more precise and suggest actual changes. 😐

[ThinkEV]

The powerwall2 charges from grid at 1.8 kW in self_consumption mode and at max. 5 kW in time based control (TBC).
Switching modes can be done with API calls, but is not supported by evcc right now.

the powerwall api is documeted here https://tesla-api.timdorr.com/energy-products/energy/commands if you want to impelement mode switching. :)

If you want to use TBC, use Netzero to update the dynamic day-ahead tariffs for best savings.