VictronMPPT-ESPHOME: Monitor Victron Devices with ESP32

Oct 13, 2026 · 5 min read

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ADUM1201 isolator wiring between a Victron VE.Direct port and an ESP board

What You Will Build and Why

Victron Energy's solar chargers, battery shunts and inverters all carry a small four-pin VE.Direct port that streams live telemetry over a simple serial protocol once per second. Without extra hardware or a paid subscription you can read panel voltage, battery voltage and current, state of charge, yield totals, error codes and dozens of other fields.

This project wraps that serial stream in an ESPHome external component. Once flashed, your ESP32 or ESP8266 appears in Home Assistant as a device with fully typed sensors — no custom parsing, no MQTT juggling, no cloud dependency. You get real-time solar data on a local network with the same YAML workflow you already use for every other ESPHome node.

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What You Need

Hardware

• Any Victron device with a VE.Direct port (MPPT charger, SmartShunt, Phoenix Inverter, Orion XS, Blue Smart charger, and more)
• An ESP32, ESP8266, BK72xx or RP2040 development board
• A JST-PH 2.0 mm four-pin cable or bare wires to reach the VE.Direct port
• Important: check the TX voltage of your Victron device before wiring. Some models output 5 V; others output 3.3 V. If your device is 5 V, add a resistor voltage divider or a logic-level converter between the Victron TX pin and the ESP RX pin to avoid damaging the microcontroller
• Optional but recommended: an ADUM1201 digital isolator for galvanic isolation between the Victron device and the ESP, protecting both sides from ground loops or transients

Software

• ESPHome 2024.6.0 or higher (pip3 install esphome)
• A working ESPHome or Home Assistant installation
• Git (to clone the example files)

Typical use cases

How It Works

The VE.Direct protocol is a one-way, human-readable serial stream. The Victron device transmits labelled key-value pairs at 19200 baud, one complete frame per second. The component opens a UART listener on the ESP, parses every label it recognises, and maps each one to an ESPHome sensor entity.

Because the communication is read-only, only the TX pin of the Victron device (wired to the RX pin of the ESP) is needed. The Victron RX line is not connected in a minimal setup. The component publishes sensor updates each time a valid frame arrives. You can slow down Home Assistant update frequency using ESPHome's built-in throttle filter without losing any data on the device side.

Galvanic isolation via the ADUM1201 chip is the recommended production approach. The VE.Direct 5 V supply pin is strictly limited to 10 mA average (20 mA burst), far below what an ESP draws, so the ESP must be powered independently — never from the VE.Direct port.

Wiring

The minimal connection uses three wires. Match RX/TX pin names to your board variant.

              UART-TTL
┌────────────────┐                ┌──────────────────┐
│           GND o│<-------------->│o GND             │
│ Victron    TX o│--------------->│o D7 / GPIO16     │
│ Charger    RX o│  (not used)    │  ESP32/ESP8266   │
│            5V o│  (not used)    │                  │
└────────────────┘                └──────────────────┘

For the insulated connection using an ADUM1201, the wiring table from the README maps VE.Direct pins through both sides of the isolator:

Note: if you leave the Victron RX line unconnected, still tie the ADUM1201 VIB pin to VDD1 or GND1 so it is not left floating.

Build and Flash

Step 1 — Install ESPHome and clone the repo

pip3 install esphome
git clone https://github.com/KinDR007/VictronMPPT-ESPHOME.git
cd VictronMPPT-ESPHOME

Step 2 — Create your secrets file

cat > secrets.yaml <<EOF
mqtt_host: MY_MQTT_HOST
mqtt_username: MY_MQTT_USERNAME
mqtt_password: MY_MQTT_PASSWORD
wifi_ssid: MY_WIFI_SSID
wifi_password: MY_WIFI_PASSWORD
EOF

Step 3 — Flash the example configuration

esphome run esp8266-example.yaml

Alternatively, add the component directly to any existing ESPHome node by pasting this into your YAML:

external_components:
  - source: github://KinDR007/VictronMPPT-ESPHOME@main

uart:
  id: uart_0
  tx_pin: D8   # Not used — communication is read-only
  rx_pin: D7
  baud_rate: 19200
  rx_buffer_size: 256

victron:
  id: victron0
  uart_id: uart_0

sensor:
  - platform: victron
    victron_id: victron0
    panel_voltage:
      name: "Panel voltage"
    battery_voltage:
      name: "Battery voltage"
    battery_current:
      name: "Battery current"

The uart_id and victron_id keys are optional when only one UART and one Victron device are configured. All individual sensors are optional — include only the ones you need.

Step 4 — Debugging

If data does not appear, flash the debug example to capture the raw serial stream and open a GitHub issue with the log output:

esphome run debug-esp8266-example.yaml

Extending the Build and Known Limitations

Ideas to extend

• Add ESPHome's throttle filter on any sensor to reduce the update rate sent to Home Assistant without losing resolution on the device
• Combine with a display component (SSD1306, ILI9341) to show panel power and battery SOC on a local screen without Home Assistant
• Use the state_of_charge, time_to_go and error_code sensors to drive automations — send a notification when the battery drops below a threshold or when an error code appears
• For installations with multiple Victron devices, the component supports multiple UART buses, each with its own victron block
• The yield_today, yield_yesterday, amount_of_charged_energy and amount_of_discharged_energy historical sensors give you a full energy dashboard without any server-side processing

Limitations to be aware of

• The VE.Direct port cannot power the ESP. You must supply the ESP from a separate 3.3 V or 5 V source
• The 5 V logic level on some Victron devices will damage a 3.3 V ESP input if connected directly — always measure the TX voltage before wiring
• Communication is strictly read-only in the default configuration; sending commands to the Victron device is not part of this component
• The component has been tested on the specific models listed in the README; behaviour on unlisted models may vary and should be verified with the debug firmware first

Facts in this article come from the project's public README and GitHub metadata at the time of writing. Images belong to their respective owners and link back to the original source.