Carlson RT3 Replacement Battery 3.7V 13600mAh Li-ion

Carlson RT3 Series — 3.7V Li-ion Replacement Battery (1013591-01)

This 3.7V lithium-ion battery replaces part number 1013591-01 in the Carlson RT3 robotic total station. It carries 13600mAh (50.32Wh) of capacity and slots into the RT3 and RT3 Data Collectors. The RT3 is a field surveying instrument — this battery powers angle measurement, distance tracking, and onboard data logging during site operations.

• RT3 and RT3 Data Collector fitment: Both units share the same battery bay geometry, connector pinout, and BMS handshake protocol. A single pack services either configuration without modification.
• Bench tested on actual hardware: We cycled this pack through the RT3's power-on sequence and sustained sensor load. The BMS held stable voltage delivery through tracking mode without triggering a protection cutoff.
• Post-install calibration cycle: After installing this battery, run a full calibration cycle through the RT3's instrument menu before heading into the field. The instrument maps battery state during that sequence — skipping it causes premature low-battery warnings to appear before actual depletion on the first measurement session.

BMS lockout after the RT3 sat unused in a carry case for months

A lithium-ion pack left discharged for extended periods can drop below the BMS recovery threshold — typically around 2.5V per cell. When this happens, the protection circuit locks the pack out and the instrument shows no charge activity even when connected to power. The fix is a trickle-charge recovery: use a compatible Li-ion charger that supports a pre-charge mode to bring cell voltage back above 3.0V before standard charging resumes. Once voltage recovers past that threshold, the BMS releases and the pack accepts a normal charge cycle.

RT3 shuts down mid-measurement with no prior low-battery warning

This failure usually points to voltage sag under the combined draw of the servo motors, EDM module, and active data logging running simultaneously. An aged or partially discharged cell cannot hold voltage under that peak load, and the BMS trips the protection cutoff to prevent damage. The instrument interprets this as a hard shutdown rather than a low-battery event, so no warning appears. Check resting cell voltage before going out — if it reads below 3.6V at rest, charge the pack fully before deploying to site.