Dual-Path Fast Charging Technology Development Background

Introduction

As the Meta Quest ecosystem gradually matures, users have a growing demand for extended battery life, prompting the emergence of various battery strap products. However, in the pursuit of battery capacity, many battery solutions on the market have introduced new issues. To increase battery life, many products simply add more battery capacity, resulting in overly heavy headsets. Some low-cost solutions suffer from low charging efficiency and long charging times, significantly affecting the user experience. Furthermore, certain products exaggerate their specifications or lack complete certifications, compromising safety. These issues pose additional challenges for users when making a choice.

Technical Approach

Most battery head straps on the market currently use single-path charging or pseudo-dual-path non-fast charging technology. Many manufacturers attempt to improve battery life by simply increasing battery capacity, which often creates additional problems.

1. Single-Path Solution: This solution is equipped with only one DC-DC system. During charging, it first powers the HMD and only switches to battery charging once the HMD is fully charged. This process takes a long time and provides a subpar user experience.

2. Pseudo Dual-Path Solution: Building on the single-path approach, this solution forcibly distributes current to both the HMD and the battery. In some cases, the charging efficiency is even lower than that of the single-path solution. When either the HMD or the head strap enters constant-voltage charging mode, the charging power is minimal, yet it still occupies a fixed share of the charger’s power, leading to inefficiency.

After studying the market and recognizing these limitations, we developed the Dual Flash Charging(DFC), a true dual-path approach to fast charging

Dual Flash Charging:

Utilizing two separate DC-DC converter systems, both of which support the USB PD protocol, this approach dynamically adjusts charging power as needed, ensuring maximum efficiency when charging both devices simultaneously. This significantly reduces charging time, greatly enhancing the user experience. While the cost is higher, the added value is substantial.

Key Components of Dual Flash Charging:

1. Two independent DC-DC power management modules.

2. Both modules must support the PD protocol.

3. Each DC-DC module should provide up to 22.5W of power.

Meeting these criteria allows for true dual-path fast charging. Our testing shows that Dual Flash Charging can reduce the total charging time from 6 hours to 2.5 hours. With just one hour of charging, the VR device and battery head strap can reach 60-65% charge, supporting 2-3 hours of usage.

The Choice of 5300mAh Battery Capacity

• Reduced Weight and Balance: Choose 5300mAh battery can keep the device light and balanced, weighing just 120g.
• Optimized Battery Life: Research indicates that 4-6 hours of battery life fulfills the needs of most users.
• High Energy Density Cells: High-density cells extend effective usage time.
• Quality Supply Chain: Partnering with top suppliers from the smartphone industry ensures battery quality.
• Efficient Charging: Even from a fully depleted state, the HMD and battery head strap can be fully charged in 2.5 hours, greatly improving charging efficiency.

Technical Advantages and Value

• Significantly Reduced Charging Time: Dual Flash Charging enhances the charging experience by reducing wait times.
• Lighter Headset Design: By optimizing battery capacity, we have achieved a lighter headset for more comfortable extended wear.

Conclusion

KIWI design’s Dual Flash Charging represents a comprehensive response to user needs for extended battery life, lightweight design, and minimal charging wait time. Early user testing has yielded highly positive feedback, underscoring the effectiveness and practicality of this solution,  explore our H4 Boost Halo Battery Strap featuring Dual-Path Fast Charging technology. We look forward to providing VR users with an even better experience through this technology.