Fluke BP291 10.8V Replacement Battery 5200mAh Li-ion

Fluke 190 II / 190 III Series — 10.8V Li-ion Replacement Battery (BP291)

This 10.8V, 5200mAh Li-ion battery replaces OEM part BP291 in Fluke 190 II, 190 III, 190-204, and 190-104 ScopeMeter test instruments. These are portable oscilloscope-multimeters used by field electricians and industrial technicians for waveform capture and electrical diagnostics. Same voltage rail, same connector, same BMS handshake as the original pack.

• 190 II and 190 III platform fit: The 190-series ScopeMeter shares a common battery bay and 10.8V power architecture across the II and III generations. The BMS handshake protocol did not change between generations, so this pack initialises correctly on both without firmware intervention.
• Bench tested on actual hardware: We ran this pack on a 190 II under mixed oscilloscope and multimeter load. The BMS held steady through probe initialisation spikes and did not trip during sustained waveform logging. Cell balancing activated normally on the first full charge cycle.
• Post-install calibration cycle: After fitting this battery, run a full calibration cycle through the 190-series 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 lockout after the 190-series sat unused in a carry case for months

Li-ion cells self-discharge over time, and if the pack drops below approximately 2.5V per cell, the BMS trips a deep-discharge lockout to prevent cell damage. A locked-out BMS will not respond to the instrument's power button and may not register on the charger at all. The fix is to connect the pack to the OEM charger and leave it for at least 30 minutes — most chargers apply a low-current recovery charge to bring cells back above the BMS wake threshold before switching to normal charge rate. Once the charge LED changes state, the BMS has cleared the lockout and normal charging resumes.

Instrument powers on but shuts down during USB data transfer to a PC

USB data transfer adds a secondary load on top of the active measurement circuit — the combined draw can push momentary current demand past the BMS discharge threshold, triggering a protective cutoff. This shows up specifically during transfer, not during normal measurement, which is why it catches users off guard. Check that the instrument firmware is current, as Fluke has addressed BMS communication timing in several 190-series updates. If the shutdown persists after a firmware update, fully charge the pack to 12.6V before attempting another transfer — a partially depleted cell has less headroom before the BMS trips under combined load.