Solar panel Bresser 3810030 21W USB – portable 21 W solar charger with USB output

The Bresser 3810030 21W USB is a portable 21 W solar charger with a built-in USB output designed to supply sustainable power to small electronic devices when mains electricity is not available. Its compact and lightweight construction makes it suitable for outdoor activities and emergency use, providing a simple renewable energy source for charging phones, GPS units, power banks and other USB-powered equipment. The panel is intended for mobile use and short-term charging rather than continuous high-power supply.

Advantages

The solar charger offers a 21-watt output in a foldable, transportable form factor that reduces carry weight and storage volume. The integrated USB output simplifies device connection without additional adapters. The unit is designed for outdoor durability and quick set-up, enabling straightforward placement in sunlight. It provides a low-maintenance charging option that decreases dependence on mains power and supports sustainable energy use on the go.

Suitable for

• Charging smartphones, tablets and small USB-powered devices while camping or hiking
• Maintaining GPS units, action cameras or portable lights during outdoor trips
• Supplementary charging for portable battery packs and power banks
• Emergency backup power for essential small electronics during outages

Key specifications

• Maximum power output: 21 W
• Built-in USB output for direct device charging
• Portable, lightweight and compact design for outdoor transport
• Intended for USB-powered small electronics and battery charging
• Suitable for use in outdoor conditions with direct sunlight

How to use

Place the solar panel in direct sunlight with the photovoltaic surface facing the sun and angle it to maximise exposure. Connect a USB cable from the panel’s USB output to the device you wish to charge or to a power bank. Monitor device charging status and reposition the panel as the sun moves to maintain optimal output. For storage, disconnect devices and fold or pack the panel according to the manufacturer’s folding method to protect the cells during transport.

Usage recommendations

For best performance, use the panel in full direct sunlight and avoid shaded areas. Protect devices from moisture and sudden temperature changes when charging outdoors. When charging power banks, ensure the power bank accepts solar input and monitor charging to prevent over-discharge or overheating.