Schuberth C3 Replacement Battery 3.7V 800mAh Li-Polymer

Schuberth C3 / C3 Pro — 3.7V Li-Polymer Replacement Battery

This 3.7V, 800mAh lithium-polymer cell replaces the original power pack inside the Schuberth C3 and C3 Pro helmet's integrated Bluetooth communication module. It fits the intercom and audio unit housed in the chin bar of both modular helmet variants. Dimensions are 49.20 × 19.50 × 9.20mm — confirm these against your existing cell before ordering.

• C3 and C3 Pro compatibility: Both helmets share the same communication module housing and connector pinout, so one cell fits either variant. The BMS on the module reads cell voltage at power-on — matching the 3.7V nominal keeps the firmware from logging a fault.
• Bench tested on actual hardware: We cycled this cell through the C3 module's charge circuit and confirmed the BMS completed a full handshake and reported accurate charge state across three consecutive cycles.
• First charge after fitting: Place the helmet unit on charge through the original cable for a complete cycle before taking a call. The C3 module recalibrates its charge-state counter against the new cell during that first uninterrupted charge — skipping it causes the indicator to read incorrectly for several sessions.

Why the C3 communication module cuts out mid-call on a new battery

The C3 module draws simultaneously from the audio amplifier and the Bluetooth radio during a call. That combined load pulls more current than standby does, and a new cell at storage voltage — typically around 3.6V — can sag just enough to trip the BMS undervoltage cutoff. The fix is a full charge cycle before first use. After two or three full cycles the cell's internal resistance settles and voltage sag under combined draw reduces noticeably.

Charge indicator shows full but the module shuts off after a few minutes

This happens when the module's charge counter hasn't synced with the new cell's actual capacity. The firmware retained the old cell's charge map and declared "full" before the new cell reached a true 4.2V. Pull the unit off charge, power it on briefly, then return it to charge — the module re-reads the cell voltage and resets its counter. After one complete charge from near-empty, the indicator tracks correctly.