Olympus BLN-1 E-M5 Compatible Battery 7.6V 750mAh

Olympus E-M5 / OM-D / E-M1 II — 7.6V Li-ion Replacement Battery (BLN-1)

This is a 7.6V, 750mAh (5.7Wh) Li-ion replacement for the Olympus BLN-1 battery. It fits the E-M5, OM-D, EM5, and E-M1 II mirrorless camera bodies. Drop it into the battery compartment and charge via the OEM charger or camera body before shooting.

• E-M5 and OM-D series compatibility: These bodies share the same battery bay dimensions, 7.6V voltage rail, and BLN-1 connector pinout. The BMS in each body reads the same authentication handshake, so one cell works across the platform without modification.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on an E-M5 body. The BMS accepted the cell after one full charge cycle completed inside the camera, and the battery-remaining indicator held stable across the discharge curve without erratic jumps.
• First-cycle conditioning on camera bodies: Complete the first full charge inside the camera body itself, not an aftermarket multi-charger. The E-M5 and OM-D BMS uses that initial cycle to map the cell's discharge curve and calibrate the battery percentage display accurately for subsequent use.

Why the OM-D battery percentage display reads erratically with a new BLN-1 cell

The OM-D series maps battery percentage against voltage thresholds calibrated to the original BLN-1 cell's discharge curve. A new third-party cell has a slightly different curve — it holds voltage higher through mid-discharge, then drops faster at the low end. The camera's indicator logic sees this as erratic behaviour and may jump from 50% to low warning without warning. One full charge cycle completed inside the camera body allows the BMS to recalibrate its threshold mapping to the new cell.

Shot count lower than expected when shooting with stabilisation and continuous AF active

The E-M5's 5-axis in-body image stabilisation, continuous phase-detect AF, and electronic viewfinder all draw current simultaneously — well beyond the base draw used to calculate rated shot counts. This combined load pulls the 750mAh cell down faster than single-frame shooting with the EVF off. To extend capacity per charge, switch the EVF to power-save mode and limit IBIS to the axes needed for your shooting situation. For sustained bursts, keep a second BLN-1 cell charged and ready — the battery bay swap takes under ten seconds.