SolarXiao Advanced carrier profile, 2026-10-21

The older SolarXiao 2W Advanced already supplies battery voltage and processor temperature through XIAO self telemetry on channel 1. This change adds no new physical measurements. It adds an explicit saved carrier selection, capability reporting, live self-reading CLI aliases and guidance to existing history.

The published Advanced Standard schematic uses a BQ24650 analog charger. It has no INA monitor or digital charger interface; status LEDs, charger NTC and analog setpoints are not connected to XIAO measurement/control inputs. Firmware cannot recover panel V/I, battery current/power, battery temperature or charger flags from that design.

Both existing solarxiao_33S_repeater Full and Reduced packages built and passed package, capability and runtime memory checks. Native host fault tests passed under ASan/UBSan. These are build/host results, not hardware acceptance. No firmware was installed on SEA Sherwood, which the user confirmed is unreachable. Its exact installed target, bootloader and physical revision were not verified. The earlier Mercerwood MPPT bench report does not qualify this new image on physical hardware.

See the controls guide and machine-readable validation record.

Qualified source and packages

Item	Result
Application source	`de1bb0f2e6a37b02f1a9f0995ea539c818c3abe9`
Version	`v1.18.0.1-halo-keymind-cascade-dev-de1bb0f2`
Target / hardware ID	`solarxiao_33S_repeater` / `solarxiao_33S`, unchanged
EndF OTA target	`0x3caf966e`, unchanged
Full application	597,816 bytes; body hash `C5339ADF076AEC89`
Reduced application	567,756 bytes; body hash `68D86AA255060031`
Full memory check	PASS: 150,584 internal bytes available; 76,960 required
Reduced memory check	PASS: 152,232 internal bytes available; 76,960 required
DFU ZIP, UF2, linked capabilities	PASS for both profiles
Linked carrier commands and history	PASS for both profiles
Source changes to RF/PA, bootloader, flash layout or battery protection	None

Both packaged applications retain the native MPPT marker and contain the Advanced selector, BQ24650 capability text, live XIAO-reading response, history guidance and unavailable-measurement explanation. Application body hashes and EndF identity fields were checked independently. The build's artifact manifest hashes matched every published local package, UF2 and capability file.

These packages contain compiled LoRa/Bluetooth update support. No LoRa OTA, boot, radio forwarding, charging or electrical test was performed for this image. Future deployment requires checking the destination's installed target and matching board/storage-aware bootloader; no remote update was attempted.

Host coverage

The following checks passed:

11 new carrier test methods, including the actual adapter, checked atomic writer and filesystem presence boundary: explicit/default selection, restart, corrupt/wrong-size/unreadable records, metadata errors, short writes, failed rename, corrupt publication, ambiguous public readback and explicit recovery.
Every Advanced/unconfirmed native service, read, write, action, telemetry and voltage-history path produced zero native bus calls. Live XIAO ADC/MCU reads remained available. Switching back to MPPT reloaded retained charger overrides and restored native readings/telemetry.
CLI parser boundaries, reply canaries for capacities 1..157, nonfinite/missing readings and history-included/omitted builds. The role passes its actual compiled history capability to the adapter.
Three existing MPPT test methods, covering eight core scenarios, real transport/atomic settings boundaries and telemetry permissions/channel order.
Six existing XIAO battery/startup/GPIO safety checks, including negative controls for unsafe historical GPIO sequences.

Reproduction:

python3 -m unittest discover -s test -p 'test_solarxiao*.py' -v
python3 -m unittest discover -s test -p test_xiao_battery_safety.py -v
bash build.sh build-firmware solarxiao_33S_repeater \
  --firmware-version v1.18.0.1-halo-keymind-cascade-dev \
  --radio-preset usa-cascadia --profile cascade

PlatformIO ran once at a time; the build entry point produced Full and Reduced sequentially. Local packages and logs are retained under /home/mesh/hwtest/solarxiao-advanced-20261021/.

Using the profile after a compatible update

set solar.board advanced
get solar.board
get solar capabilities
get solar readings
get solar history

The operator selects the board. A missing/unpowered I2C device never identifies Advanced automatically. The absent-record default remains MPPT for existing installations; a failed presence query must yield a complete valid record or block native access. The separately stored selection does not alter existing charger overrides. Selecting MPPT again re-enables and reloads those overrides.

Channel-1 voltage and MCU temperature are unchanged. Voltage/temperature history remains the existing 30-minute, seven-day RAM history and resets on reboot. The MCU temperature is not battery temperature, and a voltage trend does not measure charge current, solar power or charger state.