Settings reference

Settings reference

This page explains the settings available in the Web UI.

General behavior

• All settings are stored in NVS and survive a reboot.
• Numeric values are clamped to the supported range when they are saved or restored from backup.
• Saving network settings can reconfigure the current connection immediately.
• Poll Interval [ms] and Send interval [s] are different settings:
  • Poll Interval [ms] controls inverter communication over UART / RS232 / RS485.
  • Send interval [s] controls how often MQTT publishes the current state.

Network settings

Setting	What it does	Default / range	Notes
Prefer Ethernet when available	Uses Ethernet first when a supported LAN board has link.	Default: on for LAN builds, hidden on Wi-Fi-only builds	Wi-Fi stays available as fallback.
Device Name	Friendly device name shown in the UI and used for MQTT discovery metadata.	Default: Solar2MQTT	Also becomes the mDNS host name, normalized to lowercase letters, digits and dashes, for example solar2mqtt.local.
SSID	Primary Wi-Fi network.	Default: empty	If no SSID is configured, the device cannot join your normal Wi-Fi.
Password	Password for the primary Wi-Fi network.	Default: empty	Required for secured networks.
Lock to selected BSSID	Locks Wi-Fi connection to the selected access point MAC address.	Default: off	Useful for mesh or roaming environments. It only has an effect when a valid BSSID was stored from the scan list.
Fallback SSID	Secondary Wi-Fi network used if the primary one is unavailable.	Default: empty	Optional.
Fallback password	Password for the fallback SSID.	Default: empty	Optional.
Static IP	Static IP address for Wi-Fi or Ethernet.	Default: empty	Static addressing is only used when Static IP, Subnet Mask, Gateway and DNS Server are all filled with valid values. Otherwise DHCP is used.
Subnet Mask	Subnet mask for static addressing.	Default: empty	Must be valid together with the other static fields.
Gateway	Gateway for static addressing.	Default: empty	Must be valid together with the other static fields.
DNS Server	DNS server for static addressing.	Default: empty	Must be valid together with the other static fields.
Username	Enables HTTP basic authentication for the Web UI.	Default: empty	If the username is empty, Web UI authentication is disabled.
Password	Password for Web UI authentication.	Default: empty	In AP mode authentication is skipped so initial setup stays reachable. See WebUI authentication.

MQTT settings

Setting	What it does	Default / range	Notes
MQTT Host	Broker host name or IP address.	Default: empty	MQTT is disabled when this field is empty.
Port	Broker port.	Default: 1883, range 1..65535	Typical TLS port is 8883.
User	MQTT username.	Default: empty	Optional.
Password	MQTT password.	Default: empty	Optional.
Base topic	Root topic used for all publishes and subscriptions.	Default: Solar	Example: Solar/LiveData/...
Trigger topic	Topic that requests a full MQTT state publish when a message arrives.	Default: empty	Payload content is ignored. With Send interval > 0, the next publish still follows the configured interval. With Send interval = 0, the publish happens immediately.
Send interval [s]	MQTT state publish interval.	Default: 30, range 0..86400	Values greater than 0 rate-limit state publishes to this interval. 0 enables immediate mode and publishes new state as soon as it becomes available.
Use SSL/TLS	Uses TLS for the MQTT connection.	Default: off	Current firmware encrypts the connection but does not validate the broker certificate.
Enable JSON mode	Publishes grouped JSON data under <base topic>/Data.	Default: off	Intended as an alternative to only using many single-value topics. JSON mode cannot be enabled together with Home Assistant discovery.
Enable Home Assistant discovery	Publishes Home Assistant discovery topics.	Default: off	Enabling this switches JSON mode off automatically. See Home Assistant integration.

Device settings

Setting	What it does	Default / range	Notes
UART RX GPIO	ESP32 RX pin connected to the inverter interface.	Default depends on build target, range -1..48	Wrong values will break inverter communication.
UART TX GPIO	ESP32 TX pin connected to the inverter interface.	Default depends on build target, range -1..48	Wrong values will break inverter communication.
RS485 DIR GPIO	Direction pin for RS485 transceivers.	Default depends on build target, range -1..48	Use -1 if your hardware does not need a direction pin.
Poll Interval [ms]	Delay between individual inverter requests on the serial bus.	Default: 100, range 25..5000	Lower values mean faster updates but more UART / RS485 traffic and more load on sensitive devices. Higher values reduce bus load but data updates become slower. This is not the same as the full refresh time of all values because one complete PI polling cycle needs multiple requests.
DS18B20 GPIO	OneWire pin used for external DS18B20 sensors.	Default depends on build target, range -1..48	Use -1 to disable. Multiple DS18B20 sensors can share the same pin and are published as DS18B20_1, DS18B20_2, and so on.
Status LED GPIO	GPIO used for the status LED output.	Default depends on build target, range -1..48	Use -1 to disable the status LED. Blink meanings are documented on Blink Codes.
Status LED Brightness	PWM brightness for the status LED.	Default: 128, range 0..255	0 keeps the LED dark even if a pin is configured.

Default GPIOs by build target

Build target	Status LED	UART RX	UART TX	RS485 DIR	DS18B20	Ethernet
wemos_d1_mini32	2	19	23	18	21	no
esp32c3_supermini	-1	20	21	10	3	no
esp32s3_supermini	-1	16	15	7	6	no
waveshare_esp32_s3_eth	-1	17	18	15	21	yes

If you change GPIO settings and lose communication, use the Reset options or restore a known-good configuration backup.