Battery Charger GP Batteries PowerBank B421

The GP Batteries PowerBank B421 is a compact charger for household Nickel-Metal Hydride (NiMH) AAA batteries with a nominal capacity of 850 mAh. Designed for simple everyday use, the unit accepts a 5V DC input at 1A and provides a straightforward charging solution for small devices that rely on AAA NiMH cells. Its small footprint (82mm x 82mm x 27mm) and lightweight construction make it convenient to store and carry, while basic charging controls and indicators help monitor charging status.

Advantages

The charger delivers a reliable, energy-efficient charge for AAA NiMH batteries and is easy to operate with minimal setup. Its compact dimensions and low weight make it suitable for household storage and travel. The device’s 5V DC input allows charging from common USB power sources that provide 1A, enabling flexible placement and use. Built for routine charging tasks, it supports frequent battery rotation and replacement in small electronics.

Suitable for

• Charging AAA NiMH rechargeable batteries (850 mAh)
• Maintaining spare batteries for remote controls, wireless mice, and small toys
• Home use where a compact, USB-powered charger is preferred
• Users who need a basic, easy-to-store charging solution for everyday devices

When it may not be suitable

This charger is not intended for charging other battery chemistries such as lithium-ion or alkaline batteries. It is also limited to AAA-sized NiMH cells and does not support AA or specialty cell sizes. For applications that require fast charging, high-current output, or advanced battery diagnostics, a more feature-rich charger would be preferable.

Key specifications

• Supported battery chemistry: Nickel-Metal Hydride (NiMH)
• Supported battery size: AAA
• Typical battery capacity supported: 850 mAh
• Input power: DC 5 V, 1 A
• Physical dimensions: 82 mm x 82 mm x 27 mm
• Design: Compact and lightweight

How to use

Insert AAA NiMH batteries in the correct orientation into the charger’s slots and connect the unit to a 5V DC, 1A USB power source. The charger’s indicators will show charging status—observe the display or LEDs to determine when batteries are fully charged. After charging completes, disconnect the power source and remove the batteries. Follow standard safety precautions for NiMH cells: avoid charging damaged batteries and do not leave charging unattended for extended periods.

What to consider before purchase

• Compatibility with AAA NiMH batteries only; it does not charge AA, Li-ion, or alkaline cells
• Requires a 5V DC, 1A USB power source for operation
• Intended for household and occasional use rather than professional or high-rate charging

Recommendations

For best results, charge batteries at room temperature and use batteries with comparable states of charge and age in the same charging session. Store the charger in a dry place when not in use and inspect batteries for damage before charging.