DJI BSX01 Wireless Microphone Replacement Battery 3.87V 2600mAh

DJI ASB01 Wireless Microphone Charging Case — 3.87V Li-Polymer Replacement Battery (BSX01)

This is a 3.87V, 2600mAh lithium-polymer battery for the DJI ASB01 wireless microphone system. It fits the ASB01 transmitter body and the DJI MIC wireless microphone Charging Case. OEM part numbers BSX01 and BSX01-2600-3.87 both cross-reference this cell.

• ASB01 and MIC Charging Case compatibility: Both devices share the same cell format, voltage rail, and connector pinout. The BMS handshake on each unit expects a 3.87V nominal Li-Polymer cell — any deviation in voltage or connector orientation trips a fault state and blocks charging.
• Bench tested on actual hardware: We cycled this cell through the ASB01's charge management circuit and monitored BMS response at cutoff thresholds. The protection circuit tripped correctly at both the low-voltage floor and the charge-complete ceiling, with no thermal anomalies during the full charge cycle.
• Transmitter storage between shoots: If the ASB01 sits unused for several weeks, discharge the cell to around 50% before storing. The DJI MIC system's standby draw is low, but leaving a fully charged Li-Polymer cell dormant for extended periods accelerates capacity fade faster than partial-state storage does.

Why the DJI ASB01 shows a charging error immediately after a new battery is fitted

The ASB01 charging case uses a BMS handshake to verify the cell before allowing current to flow. If the replacement cell's resting voltage is significantly lower than expected — common after shipping — the charger may flag a fault before the first charge cycle begins. Seat the battery fully, confirm the contacts are clean, then connect the case to power and wait two minutes. The BMS will attempt a trickle pre-charge to bring the cell above the threshold voltage before switching to normal charge mode.

DJI MIC transmitter loses RF lock on the receiver immediately after a battery swap

Swapping the battery in the ASB01 without a proper power cycle can leave the transmitter's RF module in an undefined state, causing the receiver to lose pairing lock. This is not a pairing corruption — the transmitter simply needs to reinitialise its RF stack from a cold boot. Power the transmitter fully off, wait ten seconds, then power it back on. The receiver should re-acquire the link within a few seconds without any re-pairing steps.