About this replacement
IPB HDM 99XP / MXI-1 — 7.2V Ni-MH Replacement Battery (6471)
This is a 7.2V 4500mAh Ni-MH replacement battery for the IPB HDM 99XP and MXI-1 portable medical diagnostic devices. It replaces OEM part number 6471 and restores cordless operation during patient examinations and clinical data collection. Capacity is sourced from the product specification — 32.4Wh.
- HDM 99XP and MXI-1 platform fit: Both models share the same 7.2V Ni-MH chemistry, connector pinout, and BMS handshake protocol, which is why a single cell pack covers both. The charge IC on each device expects the same voltage window and temperature response curve from a Ni-MH cell stack.
- Bench tested on actual hardware: We cycled this pack through full charge and discharge on the HDM 99XP platform. The BMS accepted the cell stack without fault codes, and the charge termination triggered correctly at peak delta-V — the standard Ni-MH end-of-charge signal this device monitors.
- First-use self-test protocol: After installation, let the device complete its full power-on self-test without interruption. The HDM 99XP runs a BMS verification routine at startup — cutting power mid-sequence registers a false battery fault that persists across sessions until the device completes a clean reboot cycle.
Why the HDM 99XP reports a battery fault on a brand-new pack
The HDM 99XP BMS sets its pass threshold based on OEM cell chemistry characteristics developed over hundreds of cycles. A new replacement cell has not yet stabilised its internal resistance or charge acceptance curve. During startup verification, the BMS samples these parameters and compares them against stored thresholds — a fresh cell can read slightly outside tolerance on the first check. Running one complete charge-discharge cycle allows the BMS to update its learned values and clear the fault condition on the next boot.
Device will not power on after the battery pack sat in storage
Ni-MH cells self-discharge at roughly 1–2% per day at room temperature. A pack stored for several months can drop below the HDM 99XP's BMS recovery threshold — typically around 5.5V for a 7.2V pack — which causes the device to refuse to start rather than attempt to draw from a potentially damaged cell stack. Connect the battery to the charger and leave it on charge for a full cycle without attempting to power on. Once the pack climbs back above the recovery threshold, the BMS releases the lockout and the device boots normally.