About this replacement
NiKon Coolpix 2500 / 3500 / SQ — 3.7V Li-ion Replacement Battery (EN-EL2)
This is a 3.7V, 1050mAh Li-ion replacement for the NiKon EN-EL2 battery cell. It fits the Coolpix 2500, Coolpix 3500, and Coolpix SQ compact digital cameras. Slot it into the same battery compartment as the original and charge via the OEM charger or camera body before first use.
- Coolpix 2500, 3500, and SQ compatibility: All three cameras share the same EN-EL2 footprint, connector orientation, and 3.7V nominal rail. The BMS on each body reads the same voltage curve, so one cell covers all three without any hardware modification.
- Bench tested on actual hardware: We cycled this cell through the Coolpix body BMS and confirmed charge acceptance, stable discharge from 4.2V down to the 3.0V cutoff, and correct termination without false low-battery flags at mid-charge states.
- First-use charge protocol for Coolpix bodies: Run the first full charge inside the camera body or the OEM MH-55 charger — not a generic USB adapter. Some Coolpix BMS firmware requires one camera-body charge cycle to calibrate the battery-remaining indicator to the new cell's discharge curve.
Dead battery indicator on the Coolpix display despite a charged replacement cell
The Coolpix 2500 maps its battery indicator to voltage thresholds set during manufacture against the original EN-EL2 discharge curve. A new third-party cell can sit at 4.1V and still trigger a low-battery warning if the BMS hasn't completed one full reference cycle. This is a calibration issue, not a cell defect. Run one complete charge-to-4.2V, discharge-to-3.0V cycle through the camera body and the indicator will track correctly from that point forward.
Battery percentage jumping or dropping suddenly mid-shoot
This happens when the camera's voltage-to-percentage lookup table doesn't yet match the new cell's discharge curve. The Coolpix 2500 reads terminal voltage at intervals and converts it to a percentage — if the curve shape differs slightly from the OEM cell, the reading jumps at certain voltage steps. It's most visible between 50% and 20% indicated charge. One full discharge cycle through the camera body resets the reference points and stabilises the display reading.