Polaroid MH-45503 3.7V Replacement Battery 850mAh Li-ion

Polaroid MH-45503 / PR-130DG — 3.7V Li-ion Replacement Battery

This is a 3.7V, 850mAh Li-ion battery for Polaroid compact digital cameras using the MH-45503 and PR-130DG designations. It delivers 3.15Wh of capacity to power the image sensor, flash circuit, and LCD display. Dimensions are 40.20 × 35.30 × 6.10mm — verify your original cell before ordering.

• MH-45503 and PR-130DG compatibility: Both models draw from the same 3.7V single-cell architecture with identical connector placement and form factor. The BMS on these cameras reads cell voltage directly — no encrypted handshake — so a correctly sized replacement cell seats and operates without firmware rejection.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on a camera body. The BMS accepted the cell cleanly, the battery-remaining indicator tracked discharge without sudden drops, and the flash recycling circuit pulled recharge current without sag at full capacitor load.
• First charge cycle in-camera: Before your first shoot, run one full charge with the battery seated in the camera body rather than a third-party external charger. Some Polaroid compact BMS firmware maps the state-of-charge display against the first charge curve it sees — charging in-body calibrates that reading from the start.

Flash capacitor recharge current sag at low cell voltage

The flash circuit in these compact Polaroid cameras pulls a sharp current spike to recharge the capacitor between shots. As the cell voltage drops toward 3.4V, that recharge draw causes visible sag on the battery rail. The BMS may read this transient dip as a low-battery condition even when the cell still holds usable charge. If the camera shuts down mid-shoot with the indicator showing one bar, check your terminal voltage — anything above 3.5V means the cell is not empty and the body is reacting to the spike, not actual depletion.

Battery percentage jumping erratically on the LCD

Polaroid compact cameras use a voltage-threshold map to estimate remaining charge — they do not use coulomb counting. A new replacement cell has a slightly different discharge curve than the original, so the camera can misread state-of-charge and show jumpy or skipped percentage steps. This is not a fault with the cell. Run two or three full charge-to-discharge cycles through the camera body and the indicator will stabilise as the BMS learns the actual voltage profile of the new cell.