Philips SureSigns VM1 Compatible Battery 11.1V 2600mAh

Philips SureSigns VM1 / VS2+ — 11.1V Li-ion Replacement Battery (863266)

This 11.1V, 2600mAh lithium-ion battery replaces OEM part 863266 in the Philips SureSigns VM1 portable patient monitor. It also fits the Vsi, VS2+, and VS1 monitor platforms that share the same battery bay and connector. Capacity matches the original 28.86Wh specification from Philips product data.

• VM1 / VS2+ platform compatibility: These monitors share a common 11.1V three-cell architecture, the same physical connector, and a BMS handshake protocol tied to the SureSigns power management rail. A single battery spec covers all listed variants without modification.
• Bench tested on actual hardware: We cycled this battery through full charge and controlled discharge on a VM1 unit. The onboard BMS accepted the cell stack, completed charge termination normally, and reported state of charge accurately across the test cycle.
• Post-swap self-test protocol: After installing this battery, allow the VM1 to complete its full power-on self-test sequence without interruption. The device runs BMS verification at startup — cutting power during this window registers a false battery fault that persists until the next complete reboot.

VM1 not completing boot sequence on a new battery

The SureSigns VM1 runs a BMS learn cycle during its first few charge-discharge passes. On a fresh cell, the monitor's charge IC applies a conservative initial limit, which can cause the boot sequence to stall or report a battery fault before the cell has been conditioned. This is not a fault with the battery or the monitor. Run one complete charge-discharge cycle before placing the unit in clinical rotation — the BMS will calibrate its state-of-charge model and boot normally from that point forward.

Charge indicator not reaching 100% on the first charge cycle

This happens because the VM1's charge IC applies a tighter termination threshold on cells it hasn't yet profiled. The indicator may plateau at 95–98% and stay there. This is a firmware-level behaviour in the SureSigns charge controller, not a capacity defect. After one full cycle — charge to cutoff, discharge under normal monitor load, recharge to cutoff — the indicator will read accurately. Do not interrupt the second charge cycle early.