Casio TR Mini Replacement Battery NP-11 3.7V 1000mAh

Casio TR Mini / TR-M11 — 3.7V Li-Polymer Replacement Battery (NP-11A)

This is a 3.7V, 1000mAh lithium-polymer replacement for the Casio TR Mini and TR-M11 compact selfie cameras. It replaces OEM part numbers NP-11, NP-11A, and LIS1639CSPC. Slot it into either model — the connector and form factor are identical across the TR Mini lineup.

• TR Mini and TR-M11 fitment: Both cameras run the same 3.7V power rail with the same NP-11 footprint and contact orientation. The BMS in each body reads cell voltage through the same three-pin interface, so one battery covers both models without modification.
• Bench tested on actual hardware: We cycled this cell through the TR Mini body and monitored the BMS handshake on each charge cycle. The protection circuit engaged correctly at low-voltage cutoff, and the camera accepted the cell without throwing an error after one full charge from the OEM charger.
• First-use charge protocol for TR Mini: Charge this cell inside the TR Mini body — not a third-party external charger — before your first shoot. The TR Mini's BMS maps its battery-remaining display against a discharge curve it calibrates on the first in-body charge cycle. Skipping this step causes the indicator to read inaccurately from the start.

Why the TR Mini shows a dead-battery indicator on a partially charged replacement cell

The TR Mini's fuel gauge maps battery percentage to voltage thresholds set against the original cell's discharge curve. A new lithium-polymer cell has a slightly different open-circuit voltage profile, especially in the upper charge range. The camera reads the unfamiliar voltage and flags it as low or exhausted, even when the cell is at 70–80% state of charge. One full in-body charge cycle recalibrates the threshold map and resolves the false low-battery warning.

Battery percentage jumping erratically on the TR Mini display after install

Erratic percentage jumps — say, 60% dropping to 20% then bouncing back — point to the BMS reading voltage transients rather than a stable cell average. This happens when the replacement cell hasn't completed a full charge cycle inside the camera body, leaving the BMS without a calibrated reference point. It can also occur if the battery contacts inside the compartment are slightly oxidised, causing intermittent resistance. Clean the contacts with a dry cotton swab, then charge fully via the camera body until the indicator holds steady at 100V before shooting.