DIY Mobile Power Box Kit for 4x18650 Batteries with LCD Display and Dual Outputs

This mobile power box is a versatile DIY kit that allows you to construct a custom-capacity portable power bank using readily available 18650 lithium-ion batteries. By sourcing your own four batteries, you can determine the final capacity and quality of your power supply, effectively avoiding the risks and logistical troubles associated with shipping pre-assembled units containing batteries. The unit functions dually as both an external power bank for charging devices like mobile phones, tablets, and other small electronics, and as a dedicated charger for the 18650 cells themselves. Its compact dimensions of 100x84x26 mm make it a portable solution for travel, work, or home use, providing a flexible and user-controlled alternative to off-the-shelf power banks.

Features and Construction

The core design of this power box centres on user customisation and practical safety features. It provides a secure housing and intelligent circuitry for four standard 18650 cells, turning them into a cohesive power unit.

Material and Build

The construction is based around a central PCB (printed circuit board) housed within a sturdy casing, available in either black or white. This board manages the dual-input power delivery, dual-output distribution, and the independent monitoring of each battery cell. The inclusion of reverse polarity protection is a key safety aspect; if a battery is inserted incorrectly, the internal chip automatically identifies the fault and cuts power solely to that reverse polarity circuit, displaying an empty battery level on the LCD for that cell. Critically, this fault does not affect the normal operation of the other three circuits, allowing the unit to remain partially functional.

Size and Practical Fit

With external measurements of 100 mm in length, 84 mm in width, and 26 mm in depth, the power box is designed to be compact and easily portable. This size efficiently accommodates the four 18650 batteries in a side-by-side configuration along with the necessary control circuitry and LCD display. The physical build is tailored to make a robust yet travel-friendly power source that fits neatly into bags or backpacks, providing substantial custom capacity without excessive bulk.

Uses and Placement

This kit's flexibility supports a range of applications, from professional toolkits to everyday personal electronics management. Its primary value lies in putting power capacity control directly in the user's hands.

Event or Professional Use

For events, fieldwork, or professional settings where reliable off-grid power is needed, this DIY kit allows you to build a power bank with known, high-quality cells. You can select industrial-grade 18650 batteries for longer life and consistent output, creating a dependable power source for charging communication devices, cameras, or measurement equipment. The ability to charge the unit via either an 8-pin or micro USB input adds convenience, as you are not reliant on a single, potentially lost cable type. The dual outputs mean a smartphone and a tablet can be charged simultaneously during a work shift or event.

Everyday Home Use

At home, this power box serves as a central charging station for frequently used devices. It eliminates the need for multiple wall adapters by consolidating power into one portable unit. After a full charge cycle, you can unplug it and move it to any room, or take it with you around the house. It is particularly useful for managing the power needs of a family's various devices, and because you supply the batteries, you can refresh the unit's capacity simply by purchasing new 18650 cells when the old ones degrade, extending the product's useful life indefinitely.

Benefits and Buying Value

The investment in this kit translates into long-term value through reuse, reduced electronic waste, and maintained performance transparency, all grounded in its documented specifications.

Reuse and Low Maintenance

The product offers significant reuse potential. Unlike sealed power banks with non-replaceable batteries that become e-waste once their cells fail, this kit allows you to replace individual 18650 batteries as needed. This not only reduces long-term cost but also minimises environmental impact. Maintenance is straightforward: keep the unit clean, use the batteries within their specifications, and monitor their status via the LCD screen. The independent circuits mean that if one battery fails, it can be replaced without discarding the entire unit.

Why Choose This Product

Choosing this mobile power box kit means selecting transparency and control over your portable power. It directly addresses common consumer concerns about false capacity claims and low-quality cells in pre-made power banks, as you personally select the batteries. The technical features—dual inputs for charging flexibility, dual outputs for convenience, independent circuits for simultaneous charge/discharge, and the safety of reverse polarity protection—are all tangible, practical advantages supported by the product's design. It provides a commercially useful, factual solution based on measurable specs like its 100x84x26 mm size, DC 5V-1A input, and DC 5V-1A/2A outputs, without relying on invented performance claims.