Tektronix H400 Replacement Battery 10.8V 6600mAh Li-ion

Tektronix H400 / H500 / H600 Series — 10.8V Li-ion Replacement Battery (LI202S-6600)

This 10.8V, 6600mAh (71.28Wh) lithium-ion battery replaces the LI202S-6600 and NI2020 cells used in the Tektronix H400, H500, H600, and SA2600 portable patient monitors. These units are used for vital sign monitoring in clinical and transport settings where AC power is not available. Capacity figures are taken from the product data — not estimated from runtime claims.

• H400 / H500 / H600 / SA2600 platform fit: These models share the same battery bay dimensions, 10.8V nominal voltage rail, and LI202S-series connector footprint. The BMS handshake protocol is consistent across this monitor family, so one cell SKU covers the group without modification.
• Bench tested on actual hardware: We ran this cell through charge and discharge on the H400 platform. The BMS accepted the cell without fault codes, completed its verification cycle, and held voltage within the monitor's operating window under sustained display and sensor load.
• Power-on self-test sequence: After installing this battery, let the monitor complete its full startup self-test without interruption. Medical-grade BMS firmware runs a cell verification check at boot. Cutting power during that sequence causes a false battery fault that persists until the next clean reboot — it does not indicate a defective cell.

Low battery alarm on the H400 immediately after a confirmed full charge

The H400's charge IC applies a conservative acceptance threshold calibrated to a well-cycled OEM cell. A new replacement cell has a slightly different internal resistance profile in its first few cycles, which the BMS can read as below-threshold capacity. This triggers the low battery alarm even when the cell is genuinely full. Run one complete charge-to-discharge-to-charge cycle before relying on the battery indicator for clinical decisions. After that conditioning cycle, the BMS re-evaluates the cell and the alarm clears.

Monitor will not power on after the replacement cell sat in storage

Lithium-ion cells self-discharge during storage. If this battery has been on a shelf, its resting voltage may have dropped below the H400's BMS recovery threshold — typically around 9.0V for a 10.8V nominal pack — and the monitor simply will not boot. Connect the battery to the monitor's charger and leave it for at least two hours before attempting to power on. The charge IC will push a recovery current into the cell to bring it above the BMS wake threshold, after which normal charging resumes.