NiKon EN-EL5 Coolpix 3700 Replacement Battery 3.7V 1000mAh

NiKon Coolpix 3700 / 4200 / 5200 / 5900 — 3.7V Li-ion Replacement Battery (EN-EL5)

This is a 3.7V, 1000mAh (3.7Wh) Li-ion replacement cell for the NiKon Coolpix 3700, 4200, 5200, and 5900 series digital cameras, along with 17 additional compatible models. It matches the EN-EL5 OEM spec and slots directly into the same battery door. Dimensions are 54.60 × 35.36 × 7.50mm — physically identical to the original.

• Coolpix EN-EL5 platform compatibility: These Coolpix models share the same 3.7V single-cell Li-ion architecture, battery door format, and BMS communication protocol — which is why one cell covers the full range. Swapping between models in this family requires no adapters or settings changes.
• Bench tested on actual hardware: We cycled this cell through the Coolpix charging circuit and monitored the BMS handshake at first insertion. The protection circuit responded correctly to charge cutoff at 4.2V and triggered low-voltage protection at 2.75V with no false trips.
• First-cycle conditioning on Coolpix bodies: On first use, run one complete charge cycle through the OEM charger or camera body before heavy shooting. Some Coolpix BMS versions need that initial in-camera charge cycle to correctly map the cell's discharge curve to the battery-remaining indicator.

Flash capacitor recharge current sag at the end of cell life

The Coolpix 5900 and 5200 both use the onboard flash heavily in auto mode, and flash recycling draws a sharp current spike each time the capacitor recharges. As a Li-ion cell ages and internal resistance climbs, that spike causes a voltage sag that the BMS can interpret as a low-battery condition even when the cell still holds charge. The result is an early cutoff during a shooting session — not a dead battery, but a stressed one. A fresh EN-EL5 cell with low internal resistance handles the capacitor recharge current without sagging past the BMS trip threshold.

Battery percentage jumping erratically on the Coolpix display

This happens when the camera's fuel gauge hasn't mapped its voltage thresholds to the new cell's discharge curve. The OEM indicator was calibrated to the original cell's curve — a replacement cell with a slightly different mid-discharge slope reads as inconsistent. The fix is straightforward: run the new battery from full charge down to automatic shutoff without interruption, then recharge fully in the camera body. After one complete cycle, the indicator stabilises because the BMS now has a complete voltage-to-capacity reference. Confirm the charge reached 4.2V before beginning the discharge cycle.