About this replacement
Wisycom MRP61 Transmitter — 3.7V Li-ion Replacement Battery (LBP61)
This is a 3.7V, 1050mAh Li-ion replacement for the Wisycom LBP61 battery. It fits the MRP61 wireless microphone transmitter, used in professional audio production, broadcast, and live sound. The MRP61 draws continuous RF output alongside DSP processing, so a worn cell causes voltage sag and early cutoff.
- MRP61 transmitter fit: The MRP61 uses a dedicated lithium cell on a 3.7V rail. The LBP61 form factor — 40.60 × 36.26 × 7.10mm — locks into the transmitter bay with a fixed contact array. A different cell geometry will misalign those contacts and break the power path entirely.
- Bench tested on actual hardware: We ran this cell through the MRP61's combined RF-transmit and DSP load cycle. The BMS held voltage above the transmitter's low-battery cutoff threshold through full discharge, with no mid-cycle shutoff triggered by inrush from the RF stage.
- Contact maintenance before field use: The MRP61 battery contacts are recessed and collect debris during pack swaps on location. Wipe the gold contacts on both the cell and the bay with a dry lint-free cloth before each shoot. Oxidised contacts raise contact resistance, which the transmitter reads as a voltage drop and flags as low battery even on a fresh cell.
Voltage sag under simultaneous RF and DSP draw on the MRP61
The MRP61 runs RF transmission and audio DSP simultaneously — both draw from the same 3.7V cell at the same time. On a degraded cell, that combined load pulls terminal voltage below the transmitter's operating floor faster than either load would alone. The BMS interprets this as end-of-charge and triggers a protective cutoff. A fresh cell with full capacity holds the voltage rail stable through both loads without sag-induced shutdown.
Receiver fails to sync after swapping a flat LBP61 in the field
When the MRP61 loses power completely — cell fully discharged mid-session — some Wisycom receiver setups drop the RF link and do not auto-recover on restart. The transmitter comes back on frequency, but the receiver still holds the last known state and waits for a sync handshake it did not receive. Power cycle the receiver after reinserting the charged battery, then re-initiate the RF scan or pairing sequence from the receiver menu. Confirm the transmitter is transmitting before re-pairing — the RF indicator on the MRP61 should show green at 3.7V nominal.