Rechargeable Camp Lantern

Overview

A rechargeable camp lantern replaces the fuel-burning lanterns it descends from with an LED ring, a lithium-ion pack, and a switching driver. This model produces up to 400 lumens in a full 360° pattern from twelve warm-white emitters in the LED Array, runs 4.5 hours at full output from its 25.2 Wh Battery Pack, and recharges over USB-C. Because the pack is large relative to the load, the USB Charging System system also exposes a USB-A output, making the lantern a power bank that happens to glow.

Light generation

The White LED (2835, 95 CRI) emitters are 2835-package SMD parts binned at 3000 K and CRI 95, warm light that renders food and faces naturally, which matters more at a campsite than raw efficacy. Four Red LED parts provide a 620 nm mode that preserves dark-adapted vision for stargazing and attracts fewer insects than white light.

All sixteen emitters sit on the LED Board (MCPCB), an aluminium-core MCPCB. At full power the array dissipates several watts; an ordinary FR-4 board would let junction temperatures climb past 120 °C and shorten emitter life, so the metal core conducts heat through a Thermal Interface Pad into the Upper Body, which acts as the heatsink. A white Reflector Ring above the ring blocks direct glare into the user's eyes and folds that light back into the Globe & Diffuser. The frosted polycarbonate Globe Shell and inner Diffusion Film scatter the twelve point sources into one even cylinder of light; O-Ring Set seals at both globe joints keep rain out.

Power and regulation

The Battery Pack holds two Li-ion Cell, 18650 cells in parallel, 7,000 mAh at a nominal 3.6 V. The cells are joined by spot-welded Nickel Strip links rather than solder, which would overheat the cell separators. A BMS Board guards against over-charge, over-discharge, and short circuit, and a Thermal Fuse in series opens permanently at 85 °C as the last line of defence.

An unregulated LED dims visibly as a lithium cell sags from 4.2 V to 3.0 V over discharge. The Driver Electronics prevents this: a buck converter built around a Power MOSFET switch and the 10 µH Buck Inductor regulates LED current, so brightness holds constant until the protection circuit cuts off. The Microcontroller handles mode logic and dims by pulse-width modulation at a frequency far above flicker perception. Charging is managed by the Charge Controller IC, which runs the standard CC/CV profile, constant current until the cells reach 4.2 V, then a tapering constant-voltage phase. A full charge through the USB-C Receptacle at 5 V / 2 A takes about four hours.

For the power-bank function, the Boost Converter IC steps the battery voltage up to a regulated 5 V at the USB-A Output Port; a full lantern recharges a typical phone roughly twice. Both ports hide behind the captive Port Cover Flap, which is what makes the IPX4 splash rating possible.

Controls and housing

A single Power Button runs everything: short presses cycle turbo/high/low, a long press ramps brightness continuously between 5 and 400 lumens, and a double press selects red. Four Fuel Gauge LED indicators behind a Indicator Light Pipe show state of charge in 25% steps, important information two days from a wall socket.

The housing splits into the Upper Body and Base Section, closed with a Fastener Set and bumpered by a TPE TPE Bumper Overmould that absorbs the rated 1.5 m drop. The lantern can be deployed four ways: stood on its base, hung upright by the fold-flat Bail Handle, hung inverted from a tent ceiling by the recessed Hanging Hook (throwing light down onto the floor), or stuck to a vehicle panel by the three Neodymium Magnet discs in the base.

Runtime behaviour

At 400 lm the lantern draws about 5 W and runs 4.5 hours; at the 5 lm low mode the draw falls below 150 mW and runtime stretches past 200 hours. Below −10 °C lithium-ion capacity drops noticeably, so in winter the lantern is best kept inside a jacket or sleeping bag between uses. The cells are rated for roughly 500 full cycles to 80% capacity, after which the lantern still works at proportionally reduced runtime.