Biomedical 431-016 ABL 77 Compatible Battery 14.4V 3800mAh

Biomedical Radiometer America ABL 77 — 14.4V Ni-MH Replacement Battery (431-016)

This is a 14.4V, 3800mAh Ni-MH battery pack for the Radiometer America ABL 77 Blood Gas Analyzer. It replaces OEM part numbers 431-016 and B11423. The ABL 77 is a portable clinical analyzer used to measure blood oxygen, carbon dioxide, and acid-base parameters at the point of care.

• ABL 77 platform fit: The ABL 77 uses a 14.4V multi-cell Ni-MH pack with a specific connector and BMS handshake. This replacement matches that voltage rail and connector pinout so the analyzer's charge management circuit recognises the pack correctly.
• Bench tested on actual hardware: We cycled this pack through the ABL 77's charge and self-test sequence. The BMS accepted the cell chemistry without fault flags, and the charge IC reached full termination without dropping into a false-peak cutoff on the first cycle.
• Post-swap self-test protocol: After installing this battery, let the ABL 77 complete its full power-on self-test without interruption. The device runs BMS verification at startup, and cutting power mid-sequence writes a battery fault to memory that won't clear until the next complete reboot.

Why the ABL 77 rejects a new Ni-MH pack during its startup verification

The ABL 77's BMS checks cell voltage at startup against a threshold calibrated to a conditioned OEM pack. A new Ni-MH cell fresh from storage often reads slightly below this threshold even after a first charge, because Ni-MH chemistry requires one full charge-discharge cycle to redistribute electrolyte evenly across all cells. Until that first cycle completes, the BMS may flag the pack as marginal. Run one full charge-discharge cycle before placing the unit in clinical rotation to let the BMS establish a stable baseline.

Charge indicator stuck below 100% on the first charge after installation

The ABL 77 charge IC applies a conservative current limit when it detects a new or unfamiliar pack, which can make the charge indicator appear to stall between 85% and 95% on the first fill. This is the charge IC holding back until it confirms the cell temperature profile matches expected Ni-MH behaviour — not a fault with the battery. Allow the charge cycle to run to natural termination without interrupting it. After one complete cycle, the charge IC relaxes its limit and the indicator will reach 100% on subsequent charges.