BP7233-2 BIRDOG USB Plus Replacement Battery 7.2V 3000mAh Ni-MH

BIRDOG USB Plus — 7.2V Ni-MH Replacement Battery (BP7233-2)

This is a 7.2V, 3000mAh Ni-MH replacement battery for the BIRDOG USB Plus satellite signal meter. It fits the USB Plus and USB Plus satellite signal meter range used in construction, telecommunications, and utility survey work. Voltage and capacity match the original BP7233-2 specification.

• USB Plus and Plus signal meter compatibility: Both meter variants run the same 7.2V battery rail with the same physical connector and cell format. The BMS handshake is identical across the range, so one pack covers the full lineup without modification.
• Bench tested on actual hardware: We cycled this pack through the USB Plus charge and discharge sequence, confirming the BMS accepted the pack without fault codes and that cell balance held stable across multiple charge cycles.
• Post-install calibration on the USB Plus: After fitting a new pack, run a full calibration cycle through the instrument menu before deploying to the field. The USB Plus maps battery state during calibration — skipping this step causes premature low-battery warnings during your first measurement session, even when the pack is near full charge.

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

Ni-MH cells self-discharge at roughly 1–2% per day at room temperature. A pack left inside a case through an off-season can drop below the BMS recovery threshold — typically around 6.0V on a 7.2V Ni-MH pack — and the BMS enters a protection lockout. At that point the charger sees the pack as absent or faulty and refuses to begin a charge cycle. To recover, use a charger with a trickle or recovery mode that applies a low-current pre-charge pulse to bring cell voltage above the re-initialisation threshold before the main charge cycle begins.

USB Plus shuts off the moment the probe or sensor module powers up

Probe and sensor initialisation pulls a short but sharp current spike — enough to cause a momentary voltage sag on a weakened or partially discharged Ni-MH pack. If that sag drops the pack voltage below the BMS undervoltage trip point, the BMS cuts output instantly and the instrument shuts off mid-startup. This is not a device fault. Charge the pack fully before running sensor-intensive sessions, and if the problem persists on a fresh pack, check that the battery contacts inside the meter are clean and making firm contact — any resistance at the contact point amplifies the voltage drop during the spike.