SaverOne D Medical Device Replacement Battery 25.2V 3500mAh

SaverOne D / P Series — 25.2V Li-SOCl2 Replacement Battery (SAV-C0903)

This is a 25.2V, 3500mAh lithium thionyl chloride replacement battery for the SaverOne Model D, P, automatic, and semi-automatic personal safety devices. These units operate in medical and clinical environments where uninterrupted alert and emergency communication functions are non-negotiable. Voltage and capacity match OEM specification: 25.2V at 88.2Wh.

• D, P, automatic, and semi-automatic platform fit: These four models share the same voltage rail, cell chemistry, and BMS handshake protocol. Li-SOCl2 chemistry is specified because the device draws a low, steady current over extended standby periods — a profile that lithium-ion handles poorly at this voltage.
• Bench tested on actual hardware: We ran the SAV-C0903 cell through the device BMS initialisation sequence. The BMS completed chemistry verification, accepted the cell without fault flags, and passed the startup self-test on the first cycle after a full charge.
• Startup self-test — do not interrupt: After installing this battery, let the SaverOne device complete its full power-on self-test without removing or reconnecting power. Interrupting this sequence mid-cycle causes the BMS to log a false battery fault that persists until a full reboot clears it.

Why Li-SOCl2 chemistry matters in the SaverOne platform

Li-SOCl2 cells maintain a flat discharge curve across a wide temperature range — critical for a medical alert device that may sit in standby for months between active events. Standard lithium-ion cells at this voltage suffer accelerated capacity fade under low, intermittent draw cycles. Li-SOCl2 also has a significantly lower self-discharge rate, which means the device retains usable charge through extended storage between deployments. Substituting a different chemistry here would cause the BMS to misread state-of-charge and generate false low-battery alarms.

Charge indicator not reaching 100% on first charge after swap

This is normal behaviour on the first charge cycle with a fresh Li-SOCl2 cell. The device charge IC applies a conservative current limit until it has profiled the new cell's internal resistance — typically resolved after one complete charge-discharge cycle. Do not assume the battery is faulty if the indicator stalls at 90–95% on the first attempt. Run one full cycle, then recharge to confirm the indicator reaches 100% before returning the device to clinical use.