Carlson Surveyor 2 Compatible Battery 3.7V 10400mAh

Carlson Surveyor 2 / Mini 2 — 3.7V Li-ion Replacement Battery

This 3.7V, 10400mAh (38.48Wh) Li-ion battery fits the Carlson Surveyor 2 and Mini 2 field data collectors used in land surveying and construction layout. It matches the original cell voltage and physical footprint for direct installation. No OEM part number is published for this pack — match using the Fit Model and dimensions: 74.30 × 69.80 × 19.90mm.

• Surveyor 2 and Mini 2 compatibility: Both units run on the same 3.7V single-cell architecture and share the same battery bay dimensions and connector pinout. One pack covers either instrument without modification.
• Bench tested on actual hardware: We cycled this pack through full charge and discharge on a cell-level tester and confirmed the BMS responds correctly to cutoff thresholds at both ends. The protection circuit tripped cleanly at low-voltage cutoff and reset without fault on the next charge cycle.
• Post-install calibration on the Surveyor 2: After fitting a new pack, run a full calibration cycle through the instrument's system menu before heading into the field. The Surveyor 2 maps battery state during calibration — skip this and the low-battery warning fires early on your first measurement session, even with a full charge.

Surveyor 2 shutting down mid-measurement despite showing charge

The Surveyor 2 draws a sharp current spike when it activates the tilt sensor or GNSS module during a measurement sequence. If the cell's internal resistance has climbed — common in aged packs — this spike causes a momentary voltage sag below the BMS cutoff threshold, triggering shutdown even when the displayed charge level looks healthy. A new cell with lower internal resistance handles the transient load without dropping below the cutoff. If shutdowns persist after fitting a new pack, check that the instrument firmware is current, as older builds have tighter voltage-floor tolerances.

Pack not recognised after the instrument sat unused for several months

Li-ion cells self-discharge during storage, and if the Surveyor 2 sat with the battery installed, the pack may have drained below the BMS recovery threshold — typically around 2.5V per cell. At that voltage, the BMS enters a protection state and the instrument sees no pack at all, not a flat one. Connect the battery to a charger that supports a low-voltage recovery or trickle pre-charge mode and leave it for 30–60 minutes before attempting a full charge. Once the cell voltage climbs above 2.8V, the BMS re-initialises and normal charging resumes.