21x18650 Power Bank Case with Fast Charge USB & Wireless Charger

Batteries not included.

Pre-built power banks often promise big capacity but deliver disappointing performance—especially when they're filled with low-quality or counterfeit batteries. The 21x18650 Power Bank Case DIY Kit puts you in control. Choose your own trusted 18650 cells, assemble them without soldering, and create a custom power bank with massive capacity that truly meets your needs.

Why Build Your Own Power Bank?

Authentic Capacity: Use genuine 18650 batteries from trusted brands—no sand-filled fakes.

Scalable Power: With space for 21 batteries, you can achieve capacities far beyond standard retail power banks.

Cost-Effective: Repurpose quality cells from old laptop batteries or build new from trusted sources.

Complete Control: Select the version (standard, fast charge, or wireless) that matches your devices.

Welding-Free, Tool-Free Assembly

This case features spring-loaded battery slots that securely hold flat-head 18650 batteries without any soldering required. Simply:

• Ensure batteries have intact outer skins (damaged skins are unsafe)
• Use only flat-head batteries (pointed tops are incompatible)
• Verify voltage range: 3.2V–4.2V per cell
• Insert batteries with correct polarity—anti-reverse protection prevents damage if you make a mistake
• Three Versions for Different Needs
• Standard Version (5V-2.1A):
• Ideal for everyday charging needs. Reliable 2.1A output charges phones and small devices efficiently.

Quick Charge Version (5V-3A / 9V-2A / 12V-1.5A):

Supports Qualcomm Quick Charge and USB Power Delivery (PD) protocols. Delivers fast charging for compatible smartphones, tablets, and other devices.

Quick Charge + Wireless Version:

All the fast charging capabilities plus 10W Qi wireless charging. Simply place your Qi-enabled phone on top of the power bank—no cables needed.

Multiple Charging Inputs

Recharge the power bank itself through any of three input ports:

Micro USB: Universal compatibility

Lightning: Direct connection for Apple users

Type-C: Modern, reversible connector for latest devices

The higher the charging head power, the faster the recharge. For best results, use a PD or QC protocol fast charger.

Digital Display for Real-Time Monitoring

The built-in digital display shows remaining battery capacity at a glance—no more guessing when it's time to recharge.

Important Usage Notes

First-Time Setup:

• After installing batteries, the power bank needs to be plugged in to activate the display (screen may show "0" until connected).
• Initial power readings may be inaccurate; calibrate by discharging fully to 0% and recharging to 100% for 2-3 cycles.
• For best results, use batteries of the same brand and capacity

Wireless Charging Tips:

• Remove thick phone cases—they can interfere with charging
• Place device flat and centered on the charging area
• Ensure proper alignment for consistent charging

Safety Precautions:

• Do not use batteries with damaged outer skins
• Only use flat-head batteries (pointed tops are incompatible)
• Maintain correct polarity during installation
• Avoid using or storing in high-temperature environments

Fast Charge Power Bank Application:

1. Heavy Smartphone Users: Never run out of power during travel or workdays
2. Camping & Outdoor Enthusiasts: Reliable power source away from outlets
3. DIY Electronics Hobbyists: Build custom power solutions with trusted batteries
4. Emergency Preparedness: High-capacity backup for critical devices
5. Repurposing Old Cells: Give quality 18650 batteries a second life

Power Bank Case Specification:

1. Battery Compatibility: 21x flat-head 18650 (3.2V-4.2V)
2. Assembly: Welding-free, spring-loaded slots
3. Protection: Anti-reverse connection
4. Display: Digital power indicator
5. Input Ports: Micro USB, Lightning, Type-C
6. Dimensions: 170 × 84 × 62 mm

Features:

1. 21-Battery Capacity: Accommodates 21 flat-head 18650 batteries (3.2V-4.2V) for massive power storage—ideal for heavy users.
2. Welding-Free Design: No soldering required; simply insert batteries into the spring-loaded slots. Anti-reverse protection prevents incorrect installation.
3. Digital Display: Real-time power level indicator shows remaining battery capacity at a glance.
4. Multiple Input Interfaces: Charge the power bank via Micro USB, Lightning (Apple), or Type-C—compatible with most chargers.
5. Fast Charge Support: Quick Charge version delivers 5V-3A / 9V-2A / 12V-1.5A output. PD and QC protocol compatible.
6. 10W Wireless Charging: Quick Charge + Wireless version adds 10W wireless charging capability for Qi-enabled devices.
7. DIY Customization: Choose your own quality 18650 batteries—no worries about fake sand-filled cells found in pre-built power banks.