Sokkia Archer 2 Data Collector Compatible Battery 3.7V 10400mAh

Sokkia Archer 2 / FC-500 — 3.7V Li-ion Replacement Battery (1003778-01)

This 3.7V Li-ion battery replaces OEM part 1003778-01 in the Sokkia Archer 2 Data Collector and FC-500. It runs at 10400mAh (38.48Wh) — the same capacity spec as the original pack. Both devices use an identical connector and BMS handshake, so one replacement covers either unit.

• Archer 2 and FC-500 compatibility: Both units share the same 3.7V battery bay, connector pinout, and BMS communication protocol. Swapping between them requires no adaptation — the charge controller reads the same protection registers on either device.
• Bench tested on actual hardware: We ran the pack through the Archer 2's full power-on sequence, including GNSS module initialisation and active satellite lock. The BMS held stable through the initialisation current spike and did not trip the protection circuit.
• First-deployment cycle on the Archer 2: After installing, run a full calibration cycle through the Archer 2's instrument menu before heading into the field. The device maps battery state during that sequence — skipping it causes the low-battery indicator to fire early on the first real survey session.

BMS cutoff during GNSS satellite acquisition on the Archer 2

When the Archer 2 powers on and begins acquiring satellites, the GNSS module draws a short current spike as it initialises the RF front end. On a degraded or deeply discharged cell, this spike can push instantaneous draw past the BMS overcurrent threshold, tripping the protection circuit before the device fully boots. The result looks like a power-on failure, but it's a protection event — not a dead battery. A fresh, fully charged pack clears the condition because cell impedance is low enough to absorb the spike without the voltage rail sagging below the BMS cutoff point.

Archer 2 battery percentage jumping at reboot after pack replacement

After fitting a new pack, the Archer 2's charge indicator may display an erratic or inconsistent percentage for the first few power cycles. The device's internal voltage-threshold indicator is recalibrating its reference points to the new cell's discharge curve. This is normal behaviour and not a fault with the replacement pack. Run two full charge-discharge cycles through the device and the percentage display will stabilise to accurate readings.