Carlson CR Robotic Total Station Compatible Battery 7.4V 5600mAh

Carlson CR / CR+ / CRx Robotic Total Station — 7.4V Li-ion Replacement Battery

This 7.4V, 5600mAh (41.44Wh) lithium-ion battery replaces the original power pack in Carlson CR, CR+, and CRx robotic total stations. These are precision surveying instruments used for land measurement, construction stakeout, and topographic mapping. If the original pack is no longer holding charge through a full field session, this cell-for-cell replacement restores operating capacity.

• CR, CR+, and CRx platform fit: All three models share the same 7.4V battery architecture, connector pinout, and BMS handshake protocol. A single battery form factor covers the platform, so the same pack works whether the instrument is a base CR or the extended-range CRx variant.
• Bench tested on actual hardware: We cycled this pack through the CR station's power-on sequence, servo initialisation, and sustained radio communication load. The BMS handled the inrush current at motor-drive startup without tripping, and cell voltage held within the instrument's operating threshold under continuous EDM and tracking load.
• Post-install calibration cycle: After fitting this battery, run a full instrument calibration through the CR's onboard menu before going to site. The total station maps battery state during calibration — skipping this step causes the low-battery indicator to trigger prematurely on your first real measurement session, even with a full charge.

BMS cutoff during servo initialisation and prism tracking on the CR platform

When the CR's motorised head initialises — particularly during automatic prism search — the servo draws a short but sharp current spike that older or degraded cells cannot sustain. The BMS interprets this as an overcurrent condition and cuts output to protect the cells. A fresh pack with full cell capacity absorbs this inrush without dropping below the BMS trip threshold. If the instrument was powering through initialisation previously but now cuts out, the issue is almost always cell capacity loss, not a fault in the instrument itself.

Pack won't charge after the instrument sat unused in a carry case for months

Lithium-ion cells that self-discharge below approximately 2.5V per cell enter a deep-discharge state where the BMS disables the charge circuit as a protection measure. The charger sees the pack as a fault condition and stops. To recover, connect the pack to the charger and leave it for 20–30 minutes — some chargers apply a low-current trickle that brings the cell voltage back above the recovery threshold before switching to normal charge mode. If the pack does not show any charging activity after 45 minutes, the cells have dropped below recoverable voltage and the pack needs replacement. Check cell voltage with a multimeter — anything below 5.0V total (2.5V per cell) confirms the pack will not recover.