Mercury Emergency USB Power Bank - AA Battery Powered

The Mercury is an emergency USB power bank that runs on four AA batteries instead of a built-in rechargeable cell, delivering 5V output at 800mA through a single USB-A port. The device measures 79 x 34 x 34mm and weighs 40g without batteries, making it small enough to fit in a coat pocket, glove box or day pack.

Designed for situations where mains charging is unavailable — camping trips, power cuts, travel in remote areas, festivals — the Mercury lets you swap in fresh AA batteries rather than waiting for a solar panel or wall socket. Four blue LED indicators on the front panel show remaining battery capacity, with the colour changing from green (for alkaline batteries) to blue (for rechargeable NiMH batteries) to help distinguish cell type at a glance.

The 800mA output is sufficient to charge most smartphones at a usable rate, though slower than modern fast-charge standards. A typical smartphone with a 3,000mAh battery would gain approximately 20-30% charge from one set of fresh alkaline AAs, depending on the phone's charging circuit and battery condition. The output remains stable until the AA cells drop below their minimum voltage, at which point the LEDs dim and output stops.

The body is constructed from black ABS plastic with a white front panel housing the USB port, power button and LED indicators. Ventilation slots on the top surface allow heat dissipation during charging. The unit accepts both alkaline and rechargeable NiMH AA batteries but does not charge the batteries itself — it simply draws power from them to charge external devices.

Are batteries included?

No. The Mercury requires four AA batteries which are sold separately. Both alkaline and rechargeable NiMH AA batteries are compatible.

How many phone charges does one set of batteries provide?

A typical smartphone with a 3,000mAh battery gains approximately 20-30% charge from one set of fresh alkaline AA batteries. High-capacity rechargeable NiMH AAs (2,500mAh+) perform similarly. Actual charge delivered depends on the phone model and battery condition.

What's the difference between the green and blue LED indicators?

The LEDs display green when alkaline batteries are installed and blue when rechargeable NiMH batteries are detected. This helps identify which battery type is currently in use. Both colours indicate remaining capacity across four dots.

Can it charge tablets or larger devices?

The 800mA output is sufficient for tablets and larger USB devices, though charging will be slower than with higher-output power banks. Devices that require more than 5V or specific fast-charge protocols may not charge at all or will charge very slowly.