About this replacement
TechniSat Techniplus — 8.4V Ni-MH Replacement Battery (91502801)
This 8.4V, 3600mAh Ni-MH battery replaces part number 91502801 in the TechniSat Techniplus line of portable survey, test, and measurement instruments. It restores field operation when the original pack has degraded past the instrument's minimum voltage threshold. Dimensions are 118.70 × 69.50 × 18.00mm — confirm physical fit before installing.
- Techniplus instrument compatibility: The Techniplus platform runs probe modules and sensor arrays from a shared 8.4V Ni-MH rail. This part number and physical form factor are specific to that platform — the connector keying and cell count match the original BMS handshake requirements.
- Bench tested on actual hardware: We ran this pack through probe initialisation cycles and sustained sensor logging draws. The BMS held steady through the current spike at probe power-up and did not trip under continuous measurement load.
- First-use calibration cycle: 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 during your first measurement session in the field.
BMS cutoff when probe module initialises on power-up
When the Techniplus powers on, the probe module draws a short inrush current as it initialises its sensor circuitry. On a degraded original pack, this spike pushes the BMS over its overcurrent threshold and the instrument shuts off immediately — often before the display fully loads. A fresh pack with full cell charge handles this spike without tripping. If the issue persists on a new battery, verify the pack is charged above 8.0V before the first power-on attempt.
Readings resetting or dropping out mid-logging session
During a sustained logging session, sensor arrays draw continuous current that causes voltage sag across aging or partially discharged cells. When pack voltage dips below the instrument's operating floor, the Techniplus briefly cuts power to non-critical modules — which registers as a data dropout or measurement reset in the log. This is not a firmware fault. Charge the pack fully before any session where continuous logging is required, and confirm resting voltage reads at least 8.2V before starting.