Sigor Nudrop 3.7V 2600mAh Compatible Battery

Sigor Nudrop — 3.7V Li-ion Replacement Battery

This is a 3.7V 2600mAh (9.62Wh) lithium-ion cell for the Sigor Nudrop portable LED desk lamp. It replaces the original internal battery when capacity has faded after repeated charge cycles. Swapping this cell restores full operation to the lamp without replacing the entire unit.

• Nudrop lamp compatibility: The Nudrop runs its LED driver circuit directly from a single-cell 3.7V Li-ion supply. This replacement matches that voltage rail and physical footprint — 66.00 × 20.20 × 18.50mm — so the cell seats correctly and the driver receives the expected input range from 4.2V fully charged down to the low-voltage cutoff.
• Bench tested on actual hardware: We cycled this cell through the Nudrop's charge and discharge circuit. The BMS responded correctly at both ends — no false low-battery shutoff at full charge and a clean cutoff before damaging undervoltage. Brightness levels stepped correctly across all modes throughout the discharge curve.
• UV mode calibration tip: Charge the lamp fully before first use. The Nudrop's UV LED mode draws significantly more current than standard white light. A cell sitting at storage voltage — typically around 3.6–3.7V — can trigger a low-battery indication almost immediately after switching to UV mode. A full charge to 4.2V prevents this.

Why the Nudrop dims or flickers before the battery reads empty

The Nudrop's LED driver has a minimum input voltage threshold — when cell voltage sags below that point, the driver can no longer regulate output current correctly. An aged cell has higher internal resistance, so under the LED load it sags further and faster than a fresh cell at the same state of charge. This causes flickering or sudden dimming even when the lamp's indicator hasn't yet signalled low battery. Replacing the cell eliminates the resistance-driven sag and restores stable driver input across the full discharge range.

Lamp charges slowly when left on during USB charging

The Nudrop charges via USB and draws power for the LED simultaneously when left switched on during charging. The USB input current — typically 500mA to 1A depending on the source — is shared between the charging circuit and the active LED load. At maximum brightness, the lamp can consume enough of that budget to leave very little for the cell. Switch the lamp off during charging to direct the full available USB current to the battery and charge it to 4.2V before use.