Garmin 0100261810 Replacement Battery 3.7V 750mAh Li-ion

Garmin XERO C1 PRO Chronograph — 3.7V Li-ion Replacement Battery (361-00056-16)

This 3.7V, 750mAh Li-ion cell replaces OEM part 361-00056-16 in the Garmin XERO C1 PRO Chronograph and devices listed under Garmin 0100261810. The XERO C1 PRO is a ballistic chronograph that measures projectile velocity and feeds shot data to a Garmin Edge or compatible display. Capacity is 750mAh (2.78Wh), matching the original cell's footprint at 48.10 × 33.90 × 4.50mm.

• XERO C1 PRO and 0100261810 platform: Both share this cell because they run the same 3.7V power rail, use the same connector pinout, and communicate shot-logging state through the same BMS handshake. Swapping to a different voltage or form factor breaks the data handshake and causes immediate shutdown at power-on.
• Bench tested on actual hardware: We cycled this cell through the C1 PRO's full sensor initialisation sequence, including the radar module spin-up pulse that briefly spikes current draw. The BMS held without tripping, and cell voltage recovered cleanly to resting level between shot strings.
• First-session calibration after install: After fitting this cell, run a complete pairing and sensor calibration cycle through the XERO C1 PRO menu before heading to the range. The device maps battery state during this sequence — skipping it causes the low-battery warning to fire early on the first active session, even with a fully charged cell.

Why the XERO C1 PRO cuts out when the radar module initialises

The C1 PRO's radar sensor draws a sharp current spike the moment it initialises — this is the single largest instantaneous load the device places on the cell. If the replacement cell's internal resistance is elevated, that spike causes voltage to sag below the BMS cutoff threshold, and the unit shuts down before it logs a single shot. A cell that reads fully charged at rest can still fail this test. This pack was selected specifically because its impedance stayed within the window that keeps the BMS from tripping during that initialisation event.

XERO C1 PRO shows a full charge bar but shuts off after one shot string

This is a voltage-threshold indicator issue, not a capacity issue. The device's fuel gauge was calibrated to the original cell's discharge curve, and a new cell discharges along a slightly different slope — so the displayed percentage doesn't match actual remaining energy until the gauge recalibrates across a full cycle. Run the battery from 100% down to the automatic low-battery cutoff, then charge it fully without interruption. After one complete cycle the indicator will track actual cell state accurately.