Pentax D-LI50 Replacement Battery 7.4V 1500mAh

Pentax K10D / K20D — 7.4V Li-ion Replacement Battery (D-LI50)

This is a 7.4V, 1500mAh Li-ion replacement for the Pentax D-LI50 battery pack. It fits the K10D and K20D digital SLR bodies, powering the sensor, autofocus motor, and image processing during shooting and playback. Capacity matches the OEM specification at 11.1Wh.

• K10D and K20D compatibility: Both bodies use the same D-LI50 footprint, contact layout, and 7.4V nominal rail. The battery compartment, locking tab, and BMS communication line are identical across the two models, so one cell covers either body without modification.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the K10D body and confirmed the BMS handshake completes correctly. The battery-remaining indicator populated after one full charge cycle completed inside the camera body.
• First-install charge cycle on K-series bodies: Insert the new cell and charge it fully inside the camera body or using a Pentax-compatible charger before shooting. The K10D and K20D map their battery-level display against a discharge curve that the BMS calibrates on the first charge cycle — skipping this step causes the indicator to read inaccurately from the first shot.

Why the K10D battery indicator drops suddenly from half to empty

The K10D does not measure raw cell voltage in real time — it maps percentage against a stored discharge curve. A new cell with a slightly different curve shape can cause the indicator to jump from around 50% to near-empty without warning. This is a calibration gap, not a capacity fault. Running two full charge-discharge cycles inside the camera body lets the BMS remap the curve against actual cell behaviour. After that, the indicator tracks consistently through the rest of the discharge.

Camera showing dead battery indicator on a cell that still has charge

If the K10D displays a flashing battery icon and locks up shortly after inserting a replacement cell, the body has not yet accepted the new cell's resting voltage as valid. Power the camera off, remove the battery for 30 seconds, then reinsert and power on. If the fault persists, place the cell in the charger until the charge LED confirms a full cycle, then reinsert — the body accepts the cell once it reads above 8.2V at the terminals.