DIY Mobile Power Box: Custom 18650 Battery Charger and Portable Power Bank with LCD Display

This versatile mobile power box offers a practical solution for creating your own custom-capacity power bank while also serving as a dedicated charger for 18650 lithium-ion batteries. Measuring 100 x 84 x 26 mm, the unit provides dual input options via either an 8-pin connection or a Micro USB port, meaning you only need one cable to operate it. With dual outputs delivering DC 5V-1A and DC5V-2A, you can charge mobile phones, tablets, or other small electronic devices simultaneously. The integrated LCD screen clearly displays the remaining capacity for each of the four battery slots independently, giving you precise power management. Available in black or white, this kit allows you to select your own 18650 battery cores and determine the final capacity, effectively avoiding the risks associated with transporting pre-installed cells.

Features and Construction

The mobile power box combines charging and power delivery functions in one compact unit, designed for users who want to build their own portable power supply. Its construction focuses on practical, user-controlled battery management rather than pre-set configurations.

Material and Build

The unit features a plastic casing available in either black or white, housing the electronic circuitry that manages both charging and discharge functions. Inside, the independent circuit design allows batteries to charge and discharge simultaneously without influencing each other's operation. The reverse polarity protection chip automatically identifies and cuts power to any circuit where batteries are inserted incorrectly, displaying an empty battery level on the LCD for that slot while leaving other circuits unaffected. This design prioritises safety and modular control over fixed, pre-assembled power packs.

Size and Practical Fit

With dimensions of 100 mm in length, 84 mm in width, and 26 mm in thickness, the power box maintains a portable form factor suitable for carrying in bags or keeping on a desk. The four 18650 battery slots determine the overall capacity based on the cells you choose, allowing you to reject false-capacity or low-quality batteries in favour of reliable cores. The dual input and output ports are positioned for straightforward cable access, supporting the unit's role as both a charger and a power bank without requiring additional adaptors.

Uses and Placement

This product serves two primary functions: as a customisable power bank for on-the-go device charging, and as a dedicated charger for 18650 batteries. Its flexible design supports both everyday and specialised applications.

Event or Professional Use

For events, workshops, or professional settings where multiple devices need charging, the dual outputs enable you to power two phones or tablets at once. The ability to choose your own battery cores means you can select high-capacity 18650 cells for extended use between charges, making the unit suitable for trade shows, outdoor filming, or fieldwork. The LCD display provides clear, at-a-glance information on remaining capacity, which is particularly useful when managing power for critical equipment or coordinating charging schedules during longer sessions.

Everyday Home Use

At home, the power box can serve as a central charging station for small electronics, eliminating the need for multiple wall adaptors. The Micro USB input makes it compatible with common phone chargers, while the 8-pin option offers an alternative connection. Using it as an 18650 battery charger allows you to maintain spare cells for torches, vaping devices, or other battery-powered gadgets, consolidating charging tasks into one unit. The reverse polarity protection adds a layer of safety for household use, especially if different users are inserting batteries.

Benefits and Buying Value

The mobile power box delivers value through user-controlled capacity, dual functionality, and straightforward operation. Its design emphasises practical flexibility over pre-configured specifications.

Reuse and Low Maintenance

Because you supply the 18650 batteries, you can reuse cells from other devices or upgrade to higher-capacity cores as needed, extending the product's useful life. The independent circuitry means individual battery slots operate separately, so a failing cell in one slot does not compromise the others. The unit requires minimal maintenance beyond occasional cleaning of the contacts, and the absence of built-in batteries avoids the degradation issues that can affect pre-assembled power banks over time.

Why Choose This Product

This power box suits users who want to determine their own power bank capacity and select specific battery brands or specifications. It provides transparency through the LCD display, letting you monitor each cell's status rather than relying on estimated overall percentages. The dual-input design offers connection flexibility, while the reverse polarity protection reduces the risk of damage from incorrect battery insertion. By excluding batteries from the package, it also avoids the transportation restrictions and hazards associated with shipping lithium-ion cells, making it a practical choice for international customers or those who already own suitable 18650 cells.