Trimble MS5760 Replacement Battery 7.4V 4200mAh

Trimble MS5 / MS5N — 7.4V Li-Polymer Replacement Battery (MS5760)

This is a 7.4V, 4200mAh lithium-polymer replacement battery for the Trimble MS5 and MS5N rugged tablets. These tablets are used for field data collection in surveying, construction, and GIS workflows. The MS5760 cell pack matches the original voltage, capacity, and connector configuration on both MS5 variants.

• MS5 and MS5N compatibility: Both models use the same battery bay geometry, voltage rail, and BMS communication protocol. The MS5N is the updated chassis revision — the battery connector pinout and cell voltage requirements did not change between generations.
• Bench tested on actual hardware: We cycled the MS5760 cell through charge and load on the MS5 platform. The onboard BMS accepted the new cell without throwing a protection flag, and charge termination triggered cleanly at 8.4V as expected for a 7.4V nominal Li-Polymer pack.
• Fuel gauge recalibration after swap: After fitting this battery, run the MS5 down to automatic shutoff under normal field load — GPS active, screen on — then charge uninterrupted to 100%. This forces the fuel gauge IC to recalibrate its state-of-charge model against the new cell and clears the inaccurate percentage readings that appear immediately after a battery swap.

Why the MS5 shuts down between 15–25% remaining

The MS5 runs a combined load — backlit display, active GPS receiver, and wireless radios simultaneously. Under that combined draw, cell voltage drops faster than the fuel gauge predicts from a resting state. When cell voltage hits the BMS low-voltage cutoff threshold, the tablet shuts down even though the reported percentage still looks usable. This is a fuel gauge calibration issue, not a fault with the new cell. One full discharge-to-shutoff cycle followed by an uninterrupted full charge resets the IC's discharge curve model and eliminates the premature shutoff.

MS5 showing incorrect battery percentage after replacement

The fuel gauge IC in the MS5 builds its state-of-charge estimate from the charge and discharge history of the previous cell. When a new cell goes in, that learned curve no longer matches actual cell capacity, so the reported percentage drifts — sometimes reading 80% on a nearly full charge, or dropping rapidly from 100%. The fix is a single recalibration cycle: discharge the tablet fully until it powers off on its own, then charge it to 100% without interruption. After that cycle, the IC recalculates against the new cell's actual voltage-to-capacity curve and percentage reporting stabilises.