About this replacement
SanDisk Sansa Clip Zip / Clip+ — 3.7V Li-Polymer Replacement Battery (PR-303038PL)
This is a 3.7V, 260mAh lithium-polymer battery for the SanDisk Sansa Clip Zip and Sansa Clip+ (Clip Plus) portable media players, including the SDMX18R-008GK-A57. It matches the original PR-303038PL cell at 36.45 x 30.75 x 3.20mm — a precise physical fit inside the compact housing.
- Clip Zip and Clip+ compatibility: Both players share the same internal battery bay dimensions, connector polarity, and 3.7V nominal voltage rail. A single cell revision covers the full range of these models without modification.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on a Clip Zip unit. The BMS accepted charge current without fault codes, and the protection circuit tripped correctly at the low-voltage cutoff threshold before any cell damage could occur.
- Post-swap charging protocol for the Clip Zip: After installing a new cell, connect the player to a charger before attempting to power it on. The Clip Zip's firmware can misread a fresh cell's resting voltage and refuse to boot. A 30-minute pre-charge clears that state.
Battery percentage jumping after a cell swap on the Clip Zip
The Sansa Clip Zip uses a voltage-threshold method to estimate charge level — it has no dedicated fuel gauge IC. After a cell swap, the firmware's stored reference points no longer match the new cell's discharge curve. You'll see the indicator jump between 100% and a lower value in the first few cycles. Run two or three full charge-to-cutoff cycles and the displayed percentage stabilises against the new cell's actual voltage behaviour.
Playback cutting out before the battery indicator shows empty
The Clip Zip's audio amplifier draws a brief current spike during output, which causes voltage to sag at the end of a discharge cycle. When the cell is nearly depleted, that sag briefly dips below the BMS cutoff threshold and the player shuts down — even though the indicator hasn't reached zero. This is a protection cut, not a faulty battery. Charge the unit immediately and the cell will recover. If cutouts begin happening much earlier in the cycle, the cell has aged past its usable capacity.