About this replacement
Bartec Benke 6728-70 Serie C — 4.8V Ni-MH Replacement Battery (310722)
This is a 4.8V 2000mAh Ni-MH replacement battery for the Bartec Benke 6728-70 Serie C surveying and testing instrument. It replaces OEM part numbers 310722, 91506201, and 04Z14500-2201. The pack matches the original voltage rail and connector so it seats directly into the battery compartment without modification.
- 6728-70 Serie C compatibility: The Serie C instruments in this line share a common 4.8V four-cell NiMH architecture with a matched connector and BMS handshake. Swapping to a different voltage or cell count causes the instrument to fault during initialisation, so this pack stays within the original 4.8V specification.
- Bench tested on actual hardware: We ran this pack through full charge and discharge cycles on a 6728-70 Serie C unit. The BMS accepted the pack on first contact, voltage held steady under sustained sensor load, and the charge circuit terminated cleanly at capacity without thermal event.
- First-use calibration on the 6728-70: After installing, run a full calibration cycle through the instrument menu before field deployment. The instrument maps battery state during calibration — skipping this step causes premature low-battery warnings to appear during the first measurement session even when the pack is fully charged.
BMS cutoff when the probe module initialises on the 6728-70 Serie C
When the instrument powers up a connected probe, there is a brief current spike as the probe's internal circuitry initialises. On a degraded or deeply discharged original pack, this spike is enough to trip the BMS undervoltage cutoff and shut the instrument down immediately. A fresh Ni-MH pack at full charge presents lower internal resistance, so the voltage does not sag enough to trigger cutoff during that startup transient. If the issue persists after fitting this pack, verify the probe connector pins are clean — a resistive connection amplifies the voltage drop at the same current draw.
Pack will not charge after months sitting unused in the carry case
Ni-MH cells self-discharge over time. If a pack sits unused for several months it can drop below the threshold the charger uses to detect a valid cell, and the charge cycle will not start. Place the pack in the instrument, power on, and check whether the display registers any voltage reading — this alone can confirm whether the BMS has locked out completely. If the charger still does not initiate, a brief trickle from a compatible external Ni-MH charger at 100mA for 10–15 minutes can bring the pack back above 4.0V, at which point the instrument's onboard charger will take over normally.