Power for things that
live outside.
Snowbird is the module that makes a raw cell safe to build on, charges from USB-C or solar, and reports to your code over Qwiic or Bluetooth. Charger, BMS, fuel gauge and two regulated rails on a Feather.
- 28 µA
- idle, gauge and supervisor awake
- 20 W
- solar in, MPPT, on the Pack
- 5
- chemistries, one jumper
Why Snowbird
Four things no other module does together.
Most charger boards do one job and leave the rest to you. Snowbird is the whole power path, from a bare cell to two regulated rails, with a supervisor that keeps the safety rules even when your firmware does not.
Raw cells, no external BMS
A programmable protector and fuel gauge on the board, so a bare pouch, an 18650 or a 4S pack is safe to build on. Thresholds follow the chemistry you set.
Solar and USB-C in one part
One MPPT charger with two inputs and a power path. The load runs from the input while the battery charges, and hands over without a glitch when the sun goes.
One register map, three languages
A supervisor on Qwiic with one I2C address. The same calls in Arduino, C and MicroPython, on every board in the line, with settings that survive a host reflash.
LiSOCl2 primary cells, properly
A primary-cell mode no other module offers: charging disabled in hardware, a gauge that counts out, and USB or solar still powers the load for service.
The line
One platform. Five boards.
Learn one and you have learned them all: the same pinout, the same library, the same register map, the same LEDs and pins.
Snowbird Feather 1S
$59.00 CADThe default. A complete 1S power system on a Feather.
Specifications
Snowbird Core 1S
$49.00 CADThe Feather 1S as a solder-down module for your own PCB.
Specifications
Snowbird 18650
$64.00 CADRaw cylindrical cells, the cheapest capacity there is, made safe.
Specifications
Snowbird Pack
$89.00 CAD2S to 4S packs with balancing, for robots and anything above 5 V.
Specifications
Snowbird Lite 1S
$34.00 CADThe entry price, for cells that bring their own protection.
Specifications
Inside
Five layers between your firmware and a fire.
A lithium charger has to be safe when the code is wrong. Snowbird's safety stack is five independent layers; a bug has to misconfigure two separate chips to overcharge a cell.
-
1
Chemistry jumper
Sets the voltage ceiling in hardware. Software can only select at or below it; the PRIMARY position disables charging entirely.
-
2
Charger
Charge voltage, current and the JEITA temperature profile enforced on the TS pin, with no firmware in the loop.
-
3
BMS
Independent per-cell cutoffs for overcharge, overdischarge, overcurrent, short and temperature. Safe defaults if the supervisor is absent.
-
4
Comparator
A hard over-temperature cutoff that pulls both regulators' enables low at 65 °C.
-
5
Fuse
On the battery input. The last line, and the only one that cannot be reconfigured.
One register map
Same calls on every board.
A capability register tells the library which board it is on. A call a board cannot honour returns a clear error instead of silently doing nothing.
#include <Snowbird.h>
Snowbird pmic;
void setup() {
pmic.begin(Wire);
pmic.setChemistry(Chem::LiFePO4); // refused above the jumper's ceiling
pmic.setCapacity_mAh(2000);
pmic.setChargeCurrent_mA(1000); // clamped; returns the applied value
pmic.onEvent(CHARGE_DONE | POWER_LOST | TEMP_HOLD, onPower);
}
void loop() {
Serial.printf("%d%% %d mV %d mW solar %s\n",
pmic.soc(), pmic.voltage_mV(), pmic.solarPower_mW(),
pmic.inputSource() == Input::Solar ? "sun" : "usb");
delay(5000);
}Reference builds
Three nodes, wired and measured.
Each build is a wiring card, a sketch and the numbers we got in the field. They double as the documentation examples.
Solar LoRa node
A Meshtastic-class LoRa node on a Snowbird Feather 1S with a 2000 mAh LiFePO4 cell and a 6 V panel, outdoors through a Kelowna winter.
LiFePO4 Home Assistant sensor
An indoor temperature and humidity node on an ESP32 Feather, one 18650 LiFePO4 cell, months per charge, discovered by Home Assistant with no integration work.
LiSOCl2 ten-year sensor
A water-meter pulse counter on a Snowbird Core 1S soldered to its carrier, running a decade on one ER14505 bobbin cell in primary mode.
Built in Kelowna, for January
Charge windows are the cell's, not the datasheet's.
Below 0 °C a lithium cell plates when charged. Snowbird gates charging on the cell's own thermistor, in hardware, and keeps the load running from solar in the meantime. The node survives February.
Temperature windows per chemistryBuild log
Measured, then published.
- Rev B boards are shipping The pilot run is counted into stock, the store is open for Canada and the United States, and the Tindie listing is live beside it.
- The characterization report The measured numbers from bring-up and test, which are the ones the spec sheets now carry: efficiency, idle current, gauge accuracy, BMS trips and thermals.
- Primary cells and the passivation dip Snowbird runs a lithium thionyl chloride cell in primary mode, with three independent blocks keeping charge current away from it, and a depassivation step so a shelf-aged cell reads full on day one.
Mailing list
Posts by email.
The build log, a few times a quarter. Measurements, firmware releases, stock. Double opt-in, one-click unsubscribe, no tracking pixels.