Trimble S3 Survey Replacement Battery 11.1V 5200mAh

Trimble S3 / S5 / S6 / S7 Total Station — 11.1V Li-ion Replacement Battery (79400 / 99511-30)

This is an 11.1V 5200mAh lithium-ion battery for Trimble S-Series total stations. It fits the S3, S5, S6, S7, and 33 additional confirmed models sharing the same battery bay and connector. Capacity is 5200mAh (57.72Wh) — matching the original specification exactly.

• S-Series battery platform: The S3 through S7 share a common battery bay geometry, locking tab position, and BMS communication protocol. Trimble standardised this across the platform so the same pack handles the servo drive motor, EDM module, and onboard computer from a single cell stack.
• Bench tested on actual hardware: We ran this pack on an S-Series unit and cycled through EDM activation, servo slew, and data logging simultaneously. The BMS held the output rail steady through motor-start current spikes and returned accurate state-of-charge data to the instrument display throughout.
• First field deployment tip: After installing, run a full calibration cycle through the instrument menu before taking the unit to site. The S-Series maps battery state during calibration — skipping this step causes premature low-battery warnings during the first measurement session, even with a fully charged pack.

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

Li-ion cells self-discharge over time. If a pack sits unused for several months, cell voltage can drop below the BMS protection threshold — typically around 2.5V per cell. At that point, the BMS opens the discharge circuit entirely and the instrument sees no pack at all. A standard charger may also refuse to start because the pack voltage reads as a fault condition. The fix is a low-rate recovery charge: place the pack in a compatible charger that supports recovery mode, or apply a brief trickle charge to bring cell voltage above 3.0V per cell before the BMS re-enables the output.

Instrument shuts down mid-measurement with no low-battery warning

This is a voltage sag failure, not a capacity failure. When the EDM fires and the servo drive slews simultaneously, the combined current draw can pull the pack voltage below the BMS cutoff threshold for a fraction of a second — enough to trigger an emergency shutdown. It happens more often with cells that have aged past 70% capacity, because internal resistance rises and voltage sag deepens under load. Swapping to a fresh pack usually resolves it immediately. If it continues with a new pack, check that the battery contacts in the bay are clean — oxidised contacts add resistance and worsen sag at the same draw level.