About this replacement
Bionet BM3 Pro Series — 10.8V Li-ion Replacement Battery (36L335-BIO-S)
This 10.8V 3350mAh Li-ion battery replaces the original pack in the Bionet BM3 Pro, BM3Vet Elite, BM5Vet Elite, and Elite 3 portable patient monitors. These monitors share a common battery bay, connector pinout, and BMS communication protocol across the listed models. Capacity is 3350mAh (36.18Wh) — matching the OEM specification.
- BM3 Pro and BM3Vet Elite cross-compatibility: Both models run the same 10.8V three-cell Li-ion architecture with an identical BMS handshake. The battery bay dimensions and connector locking tab are shared, so one pack covers both clinical and veterinary variants without modification.
- Bench tested on actual hardware: We cycled this battery through the BM3 Pro's startup self-test and parameter monitoring load. The BMS held voltage within spec across heart rate, SpO2, and NIBP measurement cycles with no mid-sequence cutoff.
- BMS initialisation on first installation: After fitting this battery, allow the BM3 Pro to complete its full power-on self-test without interruption. Interrupting the boot sequence before the BMS verification step finishes triggers a latching battery fault — it will not clear until the device is fully powered down and rebooted from scratch.
BM3 Pro not completing boot sequence on a new battery
The BM3 Pro runs a BMS learn cycle during its first few charge-discharge passes on a new cell. Until that cycle completes, the charge IC applies a conservative current limit and the device firmware may read state-of-charge as indeterminate. This can stall the boot sequence at the self-test screen. Run one full charge to termination, then a full discharge under normal monitoring load, then recharge before placing the unit back in clinical rotation. After that cycle, the BMS reports state-of-charge accurately and boot completes normally.
Charge indicator stalls below 100% on first charge
On the first charge, the BM3 Pro's charge IC applies a reduced current ceiling to a new cell — this is normal behaviour, not a fault with the battery or charger. The indicator may sit at 95–98% for an extended period before the charge IC declares the cycle complete. Do not interrupt charging at this point. Let the cycle run to automatic termination; the charge IC will switch to trickle mode and the indicator will reach 100% once the cell voltage stabilises at 12.6V across all three cells.