My goal was to store the solar energy in the batteries, and if the energy prices are higher, discharge into my home.

The Problem

There is no solution to control it locally, only with the app. Zendure only has a public MQTT in the internet that is not locally available, an one can only read data from it. It looked like I needed to wait until Zendure would give me a method to control the device locally.

Man, I already have the energy prices, the current energy usage of my home, even the current solar energy and the battery percentage of my Zendure system... there must be a way. And there is!

You remember my HM-800? Instead of the Hoymiles DTU, I am using a AhoyDTU. With it, I can send a limit to the Inverter. I did already set a max output of 300W in the Zendure App (because thats a little bit under the base energy usage of my home) and now I set the Inverter limit to 0%. Now the Zendure system moves all solar energy into the battery. If the limit is reverted to 100%, it moves energy into the home. Nice!

Because the AhoyDTU has MQTT, and one can set a limit, my plan was almost complete. If there only was a way to automate this...

The Solution

My current setup uses a NodeRed instance in HomeAssistant, an AhoyDTU, the Tibber API and the public Zendure MQTT.

Every hour, I get the current prices from Tibber, store them, wait 5 seconds, read the stored prices, calculate the average price and store it in an HomeAssistant Sensor named "elecricity_price_average".

Then, every time the Tibber Integration changes the price, or the battery percentage changes (I get the value from the Zendure MQTT and store it in its own sensor), I get the values with a handy "ValueGetter"-Subflow, check if it should discharge into my home (which it should when the current price is higher than the average price of the day), store the limit in a sensor and send the new limit to the inverter with MQTT.

This is my final flow:

Code

Average price calculation:

function calculateAverage(values) {
    // Check if the values array is not empty
    if (values.length === 0) {
        return 0;
    }

    // Calculate the sum of all values
    var sum = values.reduce(function(a, b) {
        return a + b;
    });

    // Calculate the average
    var average = sum / values.length;

    return average;
}

let prices = [];
// Push all prices into an array
msg.payload.forEach(function(price) {
    prices.push(price.total);
});

// the 0.00 is for an offset that can be added to the average
let result = Math.round((calculateAverage(prices) + 0.00) * 1000) / 1000

return msg = {
    "payload": result
};

Discharge condition:

// Prepare values
let battery = msg.payload.battery;
let price = msg.payload.price;
let average = msg.payload.averagePrice;
let solar = msg.payload.solarEnergy;

// Charge battery
msg.payload = "0"

// Price high -> discharge battery
if (price > average) {
    msg.payload = "100"
}

if (
    (battery <= 20 && solar > 0) ||
    (battery <= 12 && solar == 0)
) {
    // Charge battery
    msg.payload = "0"
}

// Battery full -> excess solar into home
if (battery >= 100 && solar > 0) {
    msg.payload = "100"
}

// Send new limit to inverter
return msg;

MQTT topic:

ahoydtu/ctrl/limit/0

ValueGetter Subflow:

[{"id":"f193ca922ddcefac","type":"subflow","name":"ValueGetter","info":"","category":"Vratny","in":[{"x":120,"y":260,"wires":[{"id":"c56d509f669595a3"}]}],"out":[{"x":1180,"y":260,"wires":[{"id":"8e25b00de8b09d79","port":0}]}],"env":[{"name":"entities","type":"json","value":"{}","ui":{"icon":"font-awesome/fa-bars","label":{"de":"Entitäten"}}},{"name":"topic","type":"str","value":""}],"meta":{},"color":"#3FADB5","icon":"node-red/join.svg"},{"id":"b4a9ab518ebd88d2","type":"api-current-state","z":"f193ca922ddcefac","name":"","server":"4db50fc5.1329b","version":3,"outputs":1,"halt_if":"","halt_if_type":"str","halt_if_compare":"is","entity_id":"","state_type":"str","blockInputOverrides":false,"outputProperties":[{"property":"payload","propertyType":"msg","value":"","valueType":"entityState"},{"property":"data","propertyType":"msg","value":"","valueType":"entity"}],"for":"0","forType":"num","forUnits":"minutes","override_topic":false,"state_location":"payload","override_payload":"msg","entity_location":"data","override_data":"msg","x":720,"y":260,"wires":[["b1f94791af70a145"]]},{"id":"b1f94791af70a145","type":"join","z":"f193ca922ddcefac","name":"Zusammenführen","mode":"auto","build":"object","property":"payload","propertyType":"msg","key":"topic","joiner":"\\n","joinerType":"str","accumulate":false,"timeout":"","count":"2","reduceRight":false,"reduceExp":"","reduceInit":"","reduceInitType":"","reduceFixup":"","x":910,"y":260,"wires":[["8e25b00de8b09d79"]]},{"id":"8e25b00de8b09d79","type":"function","z":"f193ca922ddcefac","name":"Filter","func":"let newMsg={};\nnewMsg.payload=msg.payload;\nnewMsg.topic = env.get(\"topic\");\nreturn newMsg;","outputs":1,"timeout":0,"noerr":0,"initialize":"","finalize":"","libs":[],"x":1070,"y":260,"wires":[[]]},{"id":"989cce5990120f96","type":"split","z":"f193ca922ddcefac","name":"","splt":"\\n","spltType":"str","arraySplt":1,"arraySpltType":"len","stream":false,"addname":"topic","x":390,"y":260,"wires":[["90c052159aac0c60"]]},{"id":"90c052159aac0c60","type":"function","z":"f193ca922ddcefac","name":"Convert","func":"msg.payload = { 'entityId': msg.payload};\nreturn msg;","outputs":1,"timeout":0,"noerr":0,"initialize":"","finalize":"","libs":[],"x":540,"y":260,"wires":[["b4a9ab518ebd88d2"]]},{"id":"c56d509f669595a3","type":"function","z":"f193ca922ddcefac","name":"Get Variable","func":"msg.payload=env.get(\"entities\");\nreturn msg;","outputs":1,"timeout":0,"noerr":0,"initialize":"","finalize":"","libs":[],"x":230,"y":260,"wires":[["989cce5990120f96"]]},{"id":"4db50fc5.1329b","type":"server","name":"Home Assistant","addon":true,"rejectUnauthorizedCerts":true,"ha_boolean":"","connectionDelay":false,"cacheJson":false,"heartbeat":false,"heartbeatInterval":"","statusSeparator":"","enableGlobalContextStore":false}]

ValueGetter Entities:

{
    "solarEnergy": "sensor.solarenergie",
    "battery": "sensor.batterie_ladung",
    "price": "sensor.electricity_price_your_address",
    "averagePrice": "sensor.electricity_price_average"
}

Es gibt zwar Möglichkeiten, das System z.B. in HomeAssistant mithilfe eines Bluetooth-Adapters zu integrieren, jedoch ist dazu natürlich ein entsprechendes Gerät in der Nähe notwendig.

Ein "kompatibles" Gerät lässt sich aber für grob 25€ nachbauen und verfügt über WiFi und kann je nach Version des Controllers, auch mit Infrarot-Fernbedienung gesteuert werden.

Erforderliche Hardware:

• Häfele LOOX5 6-Fach-Verteiler ohne Schalteranschluss (12V oder 24V - ca. 13€)

• MagicHome / MagicHue RGBW-Controller 5-24V (ca. 10€)

• Kabel (+/- 2€)

Benötigtes Werkzeug:

• Lötkolben

• Dremel

• Schraubenzieher

Umbauanleitung:

Zum Öffnen des Verteilers kann man auf der Unterseite an allen 4 Ecken mit dem Schraubenzieher das Gehäuse aus dem Verschluss an lösen, endgültiges Öffnen ist dann durch Eindrücken der Nase in der Mitte möglich.

Die Platine wird entnommen und auf der grünen Seite werden die Leiterbahnen der "-"-Verbindung unterbrochen. Zum Weiterverbinden mit anderen Boxen, muss hier nun eine Kabelverbindung zwischen den beiden Anschlüssen angelötet werden. Damit der Controller auch Strom bekommt, muss an "+" und an "-" jeweils auch ein Kabel als Zuleitung angelötet werden - Es empfiehlt sich von den gegenüberliegenden Seiten jeweils das Kabel anzulöten, damit der Platz im Gehäuse auch ausreicht.

Nach der Durchtrennung der Verbindung wird nun der bereits aus seinem Gehäuse befreite MagicHome-Controller von seiner LED-Anschlussleiste befreit und mit dem meistens mitgelieferten Doppelklebestreifen auf der weißen/beigen Seite aufgeklebt.

Nun kann man die + und - Zuleitung mit dem Controller verbinden (+ = VCC, - = GND)

Anschließend wird von Links nach Rechts von der ehemaligen Anschlussleiste, beginnend mit dem 2. (das Erste ist "+", wird aber bereits durch die Originalplatine geliefert) Lötpad die Buchse mit dem Controller verbunden:

• Pad 2 (R): J1 "-"

• Pad 3 (G): J2 "-"

• Pad 4 (B): J3 "-"

• Pad 5 (W): J4 "-"

Alternative Methode:

Im Nachgang kann die Platine nun wieder in das Gehäuse eingesetzt und dieses wieder verschlossen werden.

Unter Verwendung der "Magic Home Pro"-App lassen sich die LED-Streifen z.B. nun zeitgesteuert auch ohne Handy schalten. Weitere Funktionen, wie auf Musik reagieren, Farbe via Handykamera einstellen, Lichtanimationen etc sind natürlich auch aus der App heraus verwendbar.

Auch SmartHome-Systeme (wie zuvor erwähnter HomeAssistant) können den Controller auch direkt nach erfolgter WLAN-Konfiguration in der App verwenden und steuern.

Das fertige Teil kann nun bestehende LOOX5-Systeme für neue unabhängige LED-Streifen ergänzen oder die vorhandenen CONNECT MESH-Boxen ersetzen.