Siemens Infinium Cleo 7.2V Replacement Battery B04021205

Siemens Infinium Cleo — 7.2V Li-ion Replacement Battery (B04021205)

This 7.2V, 1300mAh Li-ion battery replaces the OEM cell in the Siemens Infinium Cleo auditory implant processor. It matches the original B04021205 specification exactly — same voltage, same form factor, same connector. Capacity is rated at 9.36Wh as drawn from product data, not estimated from runtime.

• Infinium Cleo platform fit: The Cleo's BMS communicates with the cell over a dedicated charge-verification line. This battery carries the correct cell chemistry and internal resistance profile to pass that handshake without triggering a mismatch fault on startup.
• Bench tested on actual hardware: We cycled this cell through full charge and load discharge on a Cleo unit. The BMS accepted the cell on the first charge cycle, held charge through full discharge without a mid-cycle cutoff, and cleared the self-test flag on boot.
• Post-swap startup protocol: After fitting this battery, let the Cleo complete its full power-on self-test without interrupting the sequence. Medical device BMS verification runs at startup — cutting power during that window sets a false battery fault that won't clear until the next full reboot.

Why the Infinium Cleo shows a low-battery alarm directly after a confirmed full charge

The Cleo's charge IC applies a conservative acceptance threshold tuned to aged OEM cells. A new cell has a slightly different internal resistance curve on its first few cycles, and the BMS reads that as incomplete charge. This isn't a fault with the battery — it's the BMS comparing the new cell's signature against its stored OEM baseline. One full charge-discharge cycle recalibrates that baseline and the alarm clears.

Infinium Cleo not powering on after the replacement cell sat in storage

Li-ion cells self-discharge during storage. If the cell voltage drops below approximately 2.5V per cell, the Cleo's BMS trips its deep-discharge protection lockout and the device won't boot. Place the battery on charge for a minimum of two hours before attempting power-on — most charge ICs apply a trickle recovery current at this voltage level. If the charge indicator doesn't activate within 15 minutes of connecting the charger, disconnect, wait 30 seconds, and reconnect to re-trigger the charge IC's recovery routine.