Olympus EA-BLM5 Replacement Battery 7.4V 1600mAh Li-ion

Olympus E3 / E5 / E30 — 7.4V Li-ion Replacement Battery (EA-BLM5 / BLM-5)

This is a 7.4V, 1600mAh Li-ion replacement for the Olympus EA-BLM5 / BLM-5 battery. It fits the Olympus E3, E5, and E30 digital SLR cameras. Use it as a direct swap when the original cell no longer holds charge, or carry it as a spare during extended shoots.

• E3, E5, and E30 compatibility: All three bodies share the same battery bay dimensions, contact layout, and 7.4V supply rail. The BMS handshake protocol is identical across this generation of Olympus Four Thirds DSLRs, so one cell works across all three without modification.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the E3 body. The BMS accepted the cell without error, reported state-of-charge correctly after one full charge cycle, and maintained stable output voltage under continuous burst shooting load.
• First-use charge cycle on the E3, E5, or E30: Insert the new cell and run a full charge through the OEM charger or the camera body before shooting. Some Olympus Four Thirds bodies need this cycle to calibrate the battery-remaining indicator — skipping it can cause the bar display to read inaccurately from the first shot.

Why the E3 battery indicator drops sharply in cold conditions

Li-ion cells show elevated internal resistance below 10°C. On the E3, the battery management circuit reads this resistance rise as a voltage sag and reports a lower state of charge than the cell actually holds. The indicator can jump from two bars to zero without warning, then recover once the body warms up. Keep the spare cell in an inner jacket pocket between shots — body heat is enough to keep internal resistance in the normal operating range.

Battery percentage jumping erratically on the display after fitting a new cell

The Olympus E-series indicator maps voltage thresholds to its bar segments using data from the original discharge curve. A new cell has a slightly different discharge curve until the BMS has logged a full cycle. This causes the display to remap mid-shoot — you may see the indicator drop two segments, then recover. Run one full charge-to-empty cycle through the camera body. After that cycle, the indicator stabilises and tracks the actual remaining charge accurately.