Trimble R1 GNSS Replacement Battery 3.7V 3600mAh

Trimble R1 / PG200 — 3.7V Li-ion Replacement Battery (99119-00)

This is a 3.7V, 3600mAh Li-ion battery for the Trimble R1 GNSS receiver and PG200. Both devices share the same cell format, connector, and BMS communication protocol, so one part number covers both. It restores full operational power to units used in field surveying, staking, and real-time positioning work.

• R1 and PG200 compatibility: Both units run off the same 3.7V single-cell architecture with identical connector pinouts and BMS handshake signals. The host firmware reads state-of-charge data directly from the pack — the cell spec and communication protocol have to match, or the device flags a battery fault.
• Bench tested on actual hardware: We cycled this pack under a simulated GNSS acquisition and position-logging load. The BMS held stable under the brief current spike at satellite lock-on and did not trip during sustained data logging draws.
• First-use calibration on R1: After fitting this battery, run a full calibration cycle from the R1's system menu before heading into the field. The R1 maps cell voltage thresholds during calibration — skip this and the low-battery indicator will trigger incorrectly during your first positioning session.

BMS cutoff when the R1 initialises satellite acquisition

At power-on, the R1's RF front-end and GNSS engine draw a short current spike as they initialise. A degraded or deeply discharged cell can drop below the BMS protection threshold during this spike, causing an immediate shutdown that looks like a dead battery. This is not a device fault — it is the BMS protecting an undervoltage cell. Charge the pack fully to 4.2V before the first use, and the spike will not pull the cell below cutoff.

R1 showing erratic battery percentage after pack swap

The R1 reads state-of-charge by tracking voltage against a stored discharge curve. A new cell has a slightly different resting voltage profile than the worn pack it replaced, so the percentage display will jump or read incorrectly for the first few charge-discharge cycles. This is a recalibration issue, not a faulty battery. Run two full charge and discharge cycles through normal field use, and the percentage display will stabilise to accurate readings.