INIU P51

INIU 20000mAh 22.5W Fast Charging Power Bank (Model P51) Instruction Manual

Your reliable companion for portable power.

1. Overview

The INIU 20000mAh 22.5W Fast Charging Power Bank (Model P51) is designed to provide portable and efficient power for a wide range of electronic devices. Its compact size and high capacity make it ideal for travel and daily use.

This power bank features multiple charging ports, including USB-C for both input and output, and a USB-A output port, ensuring broad compatibility. The integrated LED display provides real-time battery status, and advanced safety features protect your devices during charging.

2. What's in the Box

  • INIU 20000mAh Portable Charger (Model P51) x 1
  • 0.3M/1ft USB-C to USB-C Cable x 1
  • Travel Pouch x 1
  • User Manual x 1

3. Product Features

  • High Capacity & Compact Design: The tiniest 20,000mAh power bank, measuring just 1.94" diagonally, capable of charging an iPhone 15 four times and a Galaxy S23 three times.
  • Travel-Friendly: Easily fits into pockets, bags, and is TSA-compliant for air travel.
  • 22.5W Fast Charging: Achieve 75% power in approximately 25 minutes for compatible devices.
  • Versatile Connectivity: Equipped with 2 USB-C input/output ports and 1 USB-A output port.
  • Low-Current Device Charging: Supports charging for small devices like smartwatches and earbuds.
  • Digital Display: Clear LED screen shows the remaining battery percentage.
  • Built-in Flashlight: Provides convenient illumination when needed.
  • Advanced Safety: Features 18-Layer SmartProtect technology, passing ETL Safety Certification.

4. Setup

  1. Initial Charge: Before first use, fully charge the power bank using the provided USB-C to USB-C cable and a compatible wall adapter (not included). The LED display will show the charging progress.
  2. Check Battery Level: Press the power button once to view the current battery percentage on the LED display.

5. Operating Instructions

5.1 Charging the Power Bank

To recharge the INIU P51 Power Bank:

  1. Connect the provided USB-C to USB-C cable to one of the USB-C ports on the power bank.
  2. Connect the other end of the cable to a compatible USB wall charger (e.g., 22.5W or higher for fast charging, sold separately).
  3. The LED display will show the battery percentage increasing as it charges.

5.2 Charging Your Devices

The power bank can charge up to three devices simultaneously.

  1. Connect your device's charging cable to an available output port on the power bank (USB-C or USB-A).
  2. Connect the other end of the cable to your device.
  3. The power bank will automatically begin charging. The LED display will show the power bank's remaining charge.

Fast Charging Compatibility:

For 22.5W fast charging, ensure your device and cable support PD 3.0 or QC 4.0 protocols. The power bank will automatically detect and deliver the optimal charging speed.

5.3 Low-Current Device Charging Mode

For devices requiring lower charging currents (e.g., smartwatches, Bluetooth earbuds):

  1. Press and hold the power button for approximately 3 seconds to activate low-current mode.
  2. Connect your low-current device.
  3. To exit low-current mode, press and hold the power button again for 3 seconds, or it will automatically exit after 2 hours.

5.4 Flashlight Function

To use the built-in flashlight:

  • Double-press the power button to turn the flashlight ON.
  • Double-press the power button again to turn the flashlight OFF.

6. Maintenance

  • Store the power bank in a cool, dry place away from direct sunlight and extreme temperatures.
  • Clean the device with a soft, dry cloth. Do not use harsh chemicals or abrasive materials.
  • If not used for extended periods, charge the power bank at least once every three months to maintain battery health.
  • Avoid dropping or subjecting the power bank to strong impacts.

7. Troubleshooting

  • Device not charging: Ensure the power bank is charged. Check the charging cable and connections. Try a different cable or port.
  • Slow charging: Verify that your device and cable support fast charging. Ensure the power bank is not in low-current mode for standard devices.
  • Power bank not charging: Use the provided USB-C to USB-C cable and a compatible wall adapter. Check connections.
  • LED display not working: Press the power button once to activate the display. If it remains off, the battery might be completely depleted or there could be a fault.

8. Specifications

FeatureDetail
Model NumberP51
Battery Capacity20000mAh
Product Dimensions4.09 x 2.76 x 1.14 inches
Item Weight12.7 ounces
Input (USB-C)Up to 22.5W (PD)
Output (USB-C)Up to 22.5W (PD/QC)
Output (USB-A)Up to 22.5W (QC)
Special FeaturesDigital Display, Fast Charging, Flashlight, Slim, Pocket Size, Lightweight, Compact Design, USB-C In&Out

9. Media Gallery

9.1 Product Images

INIU 20000mAh Power Bank next to an iPhone 16 Pro Max, highlighting its smaller size.
Image: The INIU 20000mAh Power Bank (Model P51) is shown next to a larger 20,000mAh power bank and an iPhone 16 Pro Max, illustrating its compact design and 31% smaller footprint. The LED display shows 100% charge.
INIU 20000mAh Power Bank fast charging an iPhone 16 and Samsung S25.
Image: The INIU 20000mAh Power Bank is connected via USB-C to an iPhone 16, which is charging rapidly. The image highlights the 22.5W Max fast charging capability, showing an iPhone 16 at 60% and a Samsung S25 at 70% charge status.
INIU 20000mAh Power Bank with its detachable braided USB-C GoCord cable.
Image: The INIU 20000mAh Power Bank displays its detachable braided USB-C GoCord cable, which has undergone over 11,000 bending tests. The cable is shown both attached to the power bank and detached, highlighting its durability and integrated design.
INIU 20000mAh Power Bank on a passport, indicating TSA compliance and travel readiness.
Image: The INIU 20000mAh Power Bank rests on a passport and boarding pass, emphasizing its portability and TSA compliance for travel. Text indicates it provides 4.0 charges for phones and 2.0 charges for tablets.
INIU 20000mAh Power Bank highlighting its 18-Layer SmartProtect safety features.
Image: The INIU 20000mAh Power Bank is shown with an overlay highlighting its 18-Layer SmartProtect system, which has passed ETL Safety Certification. It contrasts with images of a swollen battery and an exploded battery, emphasizing the product's safety features.
INIU 20000mAh Power Bank demonstrating vast compatibility with various devices.
Image: The INIU 20000mAh Power Bank is shown connected to multiple devices, including an iPhone, iPad, and AirPods, illustrating its vast compatibility. It features 2 USB-C In/Out ports and 1 USB-A Out port, capable of charging phones, tablets, and other accessories.

9.2 Official Product Videos

No official product videos from the seller were found for this product.

10. Warranty and Support

INIU offers an industry-leading 3-year iNiu Care warranty along with lifetime technical support for the 20000mAh Portable Charger (Model P51).

For warranty claims, technical assistance, or any product-related inquiries, please contact INIU customer support through their official channels.

© 2026 INIU. All rights reserved.

Ask a question about this manual

Ask about setup, troubleshooting, compatibility, parts, safety, or missing instructions. Manuals+ will review the question and use this page’s manual context to help answer it.

After a successful submission, we securely hash the supplied account or form email before sending it to Microsoft Advertising for conversion attribution. Privacy details.