Braun 14500CY Flashlight Compatible Battery 3.7V 800mAh

Braun 14500CY — 3.7V Li-ion Replacement Battery

This is a 3.7V, 800mAh Li-ion cell in the 14500 format, replacing OEM part 14500CY in Braun handheld flashlights. The 14500 is a lithium cell the same physical size as an AA, so confirm your flashlight is rated for 3.7V before installing — it will not safely substitute for a 1.5V alkaline AA. Capacity matches the original at 800mAh (2.96Wh).

• 14500 format flashlight compatibility: Braun lights using the 14500CY share a single-cell driver circuit tuned to a 3.7V nominal input. The cell's flat-top contact and 14.6mm diameter match the factory spring and tube geometry without modification.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the bench. The protection circuit on the cell tripped correctly at low-voltage cutoff and accepted a full charge without thermal event at the rated 3.7V nominal.
• Single-cell replacement tip: If your flashlight uses more than one 14500CY cell, replace all cells at the same time from the same production batch. Mixing a fresh cell with a partially degraded one forces the weaker cell to discharge first under high-current draw, accelerating its failure.

Flashlight driver stepping down output before the battery indicator reads low

A 14500 Li-ion cell's usable voltage window sits between roughly 4.2V (full) and 3.0V (cutoff). Flashlight drivers use brownout protection — they drop the light to a lower output mode when cell voltage sags under load, even when a basic indicator still shows charge remaining. This is the driver protecting the cell from deep discharge, not a fault. Switching to a lower output mode at this point lets you continue using the light while the remaining capacity drains more evenly.

Significantly shorter runtime in turbo mode vs. standard mode

Turbo mode on most single-cell 14500 flashlights draws 5–10 times the current of standard mode. An 800mAh cell delivering that burst current hits the driver's brownout threshold much faster than it would under a steady low-draw output. This is a physics constraint of the cell's capacity, not a defect. To extend each charge cycle, use turbo in short bursts and drop back to standard or low mode for sustained illumination.