Battery

LIA comes in two battery configurations, tied to the board/enclosure revision (see Enclosure) — this is a hardware-only distinction, both revisions run the identical lia_v1 firmware (see Building the Firmware):

• V1.0 boards pair with a single 18650 Li-ion cell, held in a Keystone 54 clip on the main board (see BOM) — 3500 mAh.
• V1.1 boards pair with a 50×37×4 mm pouch cell — 1000 mAh, in exchange for a much more compact enclosure.

Charging

Charging is exposed through a magnetic 4-pin pogo connector (J2), so the enclosure never needs to be opened to charge the device — a standard USB-C-to-magnetic-pogo cable is used at the collar side.

Protection

The cell does not need a built-in protection circuit — over-discharge, over-current, and short-circuit protection are handled on the board itself by a TP4056 charge controller (see the CHG/STBY status pins below, and the protection FETs in the BOM). A plain, unprotected cell is fine.

Charge status messages

Rather than a status LED pattern, LIA reports charge state as a direct message to the configured target node (see Meshtastic Configuration):

• "Charging" once, when a charger is first detected (CHG pin, active-low).
• "Device charged" once, when the charge cycle completes (STBY pin — pulled HIGH by an external resistor while charging, pulled LOW by an internal N-MOSFET on completion).

Send CHG OFF / STB OFF as a direct message to the device to mute either message (or CHG ON / STB ON to re-enable) — see Meshtastic Configuration for the full command list.

Battery gauge

State of charge is read from a MAX17048G+T10 fuel gauge IC, which tracks cell voltage and estimates remaining capacity without needing a current-sense shunt.

Send BATTERY as a direct message to the device to get the current percentage on demand.

Note

This reads the gauge directly rather than through Meshtastic’s own battery-percentage reporting: Power::setup() (stock Meshtastic) runs its own gauge detection before the I2C bus scan that would actually find the MAX17048, so it always sees “not ready yet” at boot and falls back to reporting “no battery” indefinitely — a real bug found via a standalone, Meshtastic-free test project built specifically to isolate it (firmware/tools/battery_test/), which confirmed the gauge itself reads correctly (its voltage measurement matched an independent multimeter reading) once read the right way.

Runtime

See Power Management for the sleep/wake model that determines actual runtime. Measured runtime numbers from real hardware will be published here once available.

See also: Power Management, Accelerometer, and Microcontroller.