About this replacement
Pentax Optio E75 / M85 / E85 — 3.7V Li-ion Replacement Battery (D-LI95)
This is a 3.7V 700mAh Li-ion cell built to the D-LI95 specification. It fits the Pentax Optio E75, Optio M85, and Optio E85 compact digital cameras. The cell slots into the same battery door as the original and connects via the same three-contact terminal arrangement.
- Optio E75, M85, and E85 compatibility: All three models share the same battery bay dimensions, 3.7V voltage rail, and D-LI95 contact layout. One cell covers the full trio without modification or adapters.
- Bench tested on actual hardware: We cycled this cell through the Optio E75 body and a D-BC92 charger. The BMS accepted the cell without fault flags on both charge paths, and voltage sat at 4.17V at full charge — within OEM spec.
- First-cycle charge on these Optio bodies: Run the first full charge inside the camera body using the USB or cradle charger, not a third-party external unit. The Optio BMS maps the battery-remaining display against its first observed charge curve — skipping this step causes the indicator to read inconsistently from day one.
Why the Optio E75 shows a dead-battery icon on a replacement cell with charge in it
The Optio E75 uses a voltage-threshold system to estimate remaining charge. A new cell has a slightly different discharge curve than an aged original, so the camera's thresholds can trip early. The body interprets a mid-discharge voltage dip — common during flash recharge — as a critically low cell. Completing one full charge-discharge cycle through the camera body recalibrates the threshold mapping and clears the false indicator.
Battery percentage jumping erratically on the Optio display after fitting a new cell
This happens when the camera's stored discharge model no longer matches the actual cell. The Optio series carries a voltage-to-percentage lookup table calibrated to the original D-LI95 discharge slope. A replacement cell — even one meeting spec — can have a slightly flatter or steeper mid-range voltage curve, causing the display to jump between readings. Discharge the new cell fully through normal shooting, then charge to 100% via the camera body. After one complete cycle the display stabilises to within one bar of the actual state of charge.