Bionet Compact 5 Replacement Battery 10.8V 2600mAh

Bionet Compact 5 / Compact 7 / BM3 Series — 10.8V Li-ion Replacement Battery (10-5705)

This 10.8V, 2600mAh lithium-ion battery replaces the OEM pack in Bionet Compact 5 and Compact 7 cardiac monitors, the BM3 and BM3 Vet patient monitors, and three additional compatible models. It matches the OEM voltage rail, connector, and BMS handshake required for clinical operation. Capacity is 2600mAh (28.08Wh) as rated by the manufacturer.

• Compact 5, Compact 7, and BM3 platform fit: These models share the same 10.8V three-cell architecture, connector pinout, and BMS communication protocol, which is why one pack covers the full range. The charge IC in each device reads cell chemistry and state-of-charge from the same register set — swapping packs across models does not require reconfiguration.
• Bench tested on actual hardware: We cycled this pack through charge and discharge on a Compact 5 unit. The BMS handshake completed on first connect, the charge IC accepted the cell chemistry without fault, and the protection circuit tripped correctly at the low-voltage cutoff threshold during a controlled drain.
• Post-swap self-test protocol: After installing this battery, allow the Compact 5 to complete its full power-on self-test without interruption. The device runs a BMS verification sequence at startup — cutting power during this window registers a false battery fault that persists until the next clean reboot. Let the self-test finish before attaching to a patient.

Why the Compact 5 alarms low battery immediately after a confirmed full charge

The Compact 5 charge IC applies a conservative state-of-charge threshold tuned to cells it has already profiled. A new cell has not yet completed a learn cycle, so the BMS reads available charge against a default floor that can sit above actual delivered capacity on cycle one. The alarm clears after one full charge-discharge cycle, which allows the fuel gauge to recalibrate to the new cell's actual discharge curve. Run the device to its normal low-battery point on internal power, recharge fully, and the threshold recalibrates.

Compact 5 will not power on after the replacement pack sat in storage

Lithium-ion cells self-discharge at roughly 2–3% per month in storage. If the pack voltage drops below the BMS recovery threshold — typically around 9.0V for a 10.8V three-cell pack — the protection circuit latches off and blocks output regardless of charger connection. Connect the device to its OEM charger and leave it for a minimum of four hours without interrupting the charge. The charger applies a low-current pre-charge to lift cell voltage above the recovery floor before the BMS re-enables output. Do not attempt to power on the device during this window.