Promax CB-076 7.4V Replacement Battery 3400mAh Li-ion

Promax 8 Premium / SAT Hunter — 7.4V Li-ion Replacement Battery (CB-076)

This 7.4V, 3400mAh Li-ion battery replaces the CB-076 pack in the Promax 8 Premium, 8 Premium CATV Analyser, and SAT Hunter field instruments. All three models share the same battery bay, connector pinout, and BMS communication protocol. Capacity figure is taken from the product specification — 25.16Wh total energy.

• 8 Premium, CATV Analyser, and SAT Hunter compatibility: These instruments share a common voltage rail at 7.4V nominal and use the same physical connector with identical BMS handshake logic. One pack covers all three without modification.
• Bench tested on actual hardware: We cycled this pack through the instrument's power-on sequence and monitored the BMS response during probe initialisation. The pack held voltage without tripping cutoff during the current spike that fires when the RF front-end powers up.
• Field instrument calibration after pack swap: After installing, run a full calibration cycle through the instrument menu before field deployment. The instrument maps battery state during calibration, and skipping this step causes premature low-battery warnings on the first measurement session.

BMS cutoff during RF probe or sensor initialisation on the 8 Premium

When the 8 Premium powers up its RF front-end, it pulls a short, sharp current spike — typically lasting under 200ms. A worn or deeply discharged cell can sag below the BMS undervoltage threshold during that spike, triggering an immediate cutoff. The instrument then appears to shut down spontaneously at what looks like a healthy charge level. A fresh pack with full cell capacity handles the spike without voltage sag, keeping the BMS in normal operating range throughout initialisation.

Readings resetting or dropping mid-session during a continuous logging run

Sustained sensor load during a long logging session draws consistent current, unlike the brief spike at startup. If cell internal resistance has climbed — common in aged packs — voltage can sag progressively under that steady draw until the BMS triggers a protective cutoff, resetting the active measurement session. The instrument may reboot and return to the home screen mid-log with no error message. Replace the pack and verify open-circuit cell voltage sits at or above 7.4V before starting a multi-point logging run.