Pentax R100 Replacement Battery 6V 2100mAh BP02C

Pentax R100 / R200 / R300 Series — 6V Ni-MH Replacement Battery (BP02C)

This is a 6V, 2100mAh Ni-MH replacement battery for the Pentax R100, R200, R300, and R-100X total stations. It matches the OEM BP02C and MB02 part numbers and fits the original battery compartment without modification. Voltage and capacity are matched to the instrument's internal power management spec.

• R100 / R200 / R300 platform compatibility: These models share the same 6V battery bay, connector pinout, and BMS communication protocol. A single pack covers the full series because Pentax kept the power architecture consistent across the reflectorless total station line.
• Bench tested on actual hardware: We cycled the pack through instrument power-on, EDM initialisation, and sustained angle-and-distance logging sequences. The BMS held voltage within the instrument's operating window and did not trigger a low-battery cutoff during the EDM firing cycle.
• Post-installation calibration cycle: After fitting a new pack, run a full calibration sequence through the instrument menu before field deployment. The R100 series maps battery state during calibration — skipping this step causes premature low-battery warnings during the first measurement session, even when the pack is fully charged.

BMS lockout after a Pentax total station sits unused in the carry case for months

Ni-MH cells self-discharge during storage, and if a pack drops below approximately 4.8V total (0.8V per cell), the BMS can enter a protective lockout state. When this happens, the instrument either shows no response or a battery fault on power-on. The recovery step is to connect the pack to a Ni-MH charger that supports a low-voltage trickle recovery mode — a charger that rejects the pack outright is detecting the lockout correctly. Once the pack recovers to around 5.4V, normal charge cycles resume and the instrument recognises the battery again.

Pentax R100 shuts down mid-measurement with no low-battery warning

This is a voltage sag event, not a capacity failure. During an EDM measurement, the laser emitter and angle sensors draw a short, sharp current spike that can pull cell voltage below the instrument's cutoff threshold — even when the indicator shows adequate charge. Aged or partially discharged Ni-MH cells have higher internal resistance and sag harder under that load. Fully charging the pack before field use and avoiding top-off charging from vehicle accessory ports, which often deliver unstable current to Ni-MH chemistry, reduces the frequency of mid-session cutoffs. If shutdowns continue on a fresh charge, measure resting voltage — a healthy pack at full charge should read above 7.2V open circuit.