About this replacement
Wisycom MPR50-IEM / MPR30-ENG Series — 3.7V Li-ion Replacement Battery (MPRLBP)
This is a 3.7V, 2000mAh Li-ion cell built to the MPRLBP specification for Wisycom bodypack receivers. It fits the MPR50-IEM, MPR30-ENG, MTP60, MPR50-IFB, and three additional models in the Wisycom ecosystem. Swap it in when the original cell can no longer hold charge through a full performance or broadcast session.
- MPR50-IEM and MPR30-ENG shared cell: Both units run the same 3.7V rail with an identical footprint and connector pinout. The BMS handshake protocol is also common across the range, so one cell covers the full listed model group without any adaptation.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the MPR50-IEM. The BMS accepted the pack immediately, reported accurate state-of-charge to the unit's status display, and held voltage within spec across the full discharge curve.
- First-use cycle on Wisycom bodypacks: Before taking this receiver into a live show, run one complete charge cycle in the Wisycom charger with the unit powered off. The receiver's fuel gauge calibrates against the BMS on that first cycle — skipping it can cause the battery indicator to read incorrectly mid-performance.
Why the MPR50-IEM battery indicator drops suddenly under combined RF and audio draw
The MPR50-IEM draws current from two sources simultaneously — the DECT/wireless RF front-end and the headphone amplifier output. When both are active at full load, the combined draw creates a voltage sag that the fuel gauge reads as a much lower state-of-charge than the resting cell voltage suggests. On a degraded original cell, this sag can trigger the low-battery warning with significant capacity still remaining. A fresh 2000mAh cell with lower internal resistance reduces that sag, keeping the reported voltage above the warning threshold across a wider portion of the discharge curve.
Wisycom charger shows full charge but receiver cuts off after a short time
This happens when a new cell arrives at storage voltage — typically around 3.6V — and the charger terminates the first charge cycle earlier than expected because it reads the incoming voltage as near-full. The receiver then draws down the actual usable capacity quickly. The fix is straightforward: place the receiver in the charger, let it reach the green indicator, then remove and reinsert it to trigger a second top-up charge. After that full conditioning cycle, resting cell voltage should sit at or above 4.1V before use.