How to Choose the Battery for Smart Ring?

Smart Ring Battery Application

As wearable technology continues to evolve, smart rings are gradually transitioning from niche gadgets to mainstream consumer products. These lightweight, stylish, and feature-rich devices integrate functions such as health monitoring, notification alerts, contactless payments, and identity authentication—offering a compact alternative to traditional smartwatches. Although small in size, smart rings present significant engineering challenges behind the scenes, especially when it comes to their most critical component: the battery. In many cases, the battery ultimately determines the success or failure of a smart ring.

Smart Ring Battery Guide | How to Choose the Battery for Smart Ring?

Compared to smartwatches and fitness bands, smart rings face far greater spatial constraints. The internal space of a smart ring is typically less than 0.5 cm³, yet it must accommodate components such as a Bluetooth module, sensors, a control chip, and a battery—all while maintaining a comfortable fit for daily wear. This imposes extremely high demands on the battery’s size, energy density, safety, and structural customization.

Moreover, since smart rings are worn close to the skin on a daily basis, the battery must operate stably over the long term without any risk of leakage. This poses a significant challenge to the technical expertise and safety control systems of battery suppliers.

1、What is a Smart Ring Battery?

A smart ring battery is a miniature rechargeable power source specifically designed for use inside smart rings. It supplies consistent and stable energy to core components such as the main control chip, Bluetooth communication module, sensors, and vibration motor. Due to the strict requirements on structural volume, weight, and safety for skin contact, conventional batteries (such as traditional coin cells or 18650 lithium batteries) are not suitable. Instead, smart rings require high-energy-density, ultra-thin, compact lithium polymer batteries with flexible structural designs.

From a technical standpoint, smart ring batteries are predominantly based on curved lithium polymer (Li-Poly) battery technology. These batteries are capable of bending along the inner arc, allowing them to conform to the ring’s curved structure. This enables efficient use of limited internal space and supports flexible circuit integration to improve internal layout. Smart ring batteries are highly integrated and heavily customized micro power units, with significantly higher technical thresholds than standard consumer batteries.

2、What Are the Core Requirements for Smart Ring Batteries?

The fundamental requirements for smart ring batteries can be summarized as: ultra-compact size, high performance, strong safety, and long lifespan. Below are the five key criteria that a battery must meet when selected for smart ring applications:

2.1 Ultra-Compact Size

The internal space of a smart ring is extremely limited, typically only allowing for a battery thinner than 1mm. This places high demands on size precision and structural flexibility. Standard batteries are generally unsuitable—only custom-designed, bendable, or irregularly shaped batteries can meet these constraints.

2.2 High Energy Density

Despite their tiny size, smart rings must support multiple modules such as heart rate monitoring, sleep tracking, and vibration alerts. Therefore, the battery must offer a high energy density. A typical capacity of 10–20mAh should enable 2–5 days of continuous operation, which is considered a baseline requirement.

2.3 High Safety Standards

Since the battery is in constant contact with human skin, any swelling, leakage, or overheating poses serious safety risks. As a result, the battery must demonstrate excellent thermal stability and pass multiple international safety certifications such as UN38.3, IEC62133, MSDS, and RoHS to ensure it is safe for human use.

2.4 Fast Charging & Low Power Management

Given users’ sensitivity to charging frequency, the battery should support fast charging—typically reaching 80% capacity within 15 to 30 minutes. In addition, it should work in conjunction with low-power Bluetooth chips to reduce energy consumption and improve overall battery life.

2.5 High Consistency

In mass production, smart rings demand strict consistency across all battery units in terms of size, voltage, capacity, and internal resistance. Minor deviations can directly affect device performance and reliability.

3、Common Types of Smart Rings and Their Battery Comparisons

Based on differences in functionality, user demographics, and application scenarios, smart rings on the market can generally be categorized into the following types. Battery configurations vary accordingly, depending on the complexity of features and power consumption requirements:

3.1 Health Monitoring Smart Rings

These rings focus on tracking vital signs such as heart rate, blood oxygen levels, sleep quality, and stress levels. Representative products include the Oura Ring and Circular Ring. They are equipped with high-precision photoplethysmographic sensors and data processing chips, which require long battery life (typically at least 3 days) and strong temperature adaptability. Battery capacities for this category usually range from 15 to 30mAh and rely on high-energy-density lithium polymer batteries.

3.2 Notification & Interaction Smart Rings

Examples include the Motiv Ring and NFC Ring, which emphasize call alerts, message notifications, touch gestures, and daily interactions. These rings primarily rely on Bluetooth communication and vibration feedback. Their battery needs focus on compatibility with low-power Bluetooth modules and support for fast charging. The typical battery capacity for these models ranges from 10 to 20mAh.

3.3 Payment and Identity Authentication Rings

These rings feature NFC, fingerprint authentication, and encryption chips, making them suitable for access control, public transit, and smartphone unlocking. Notable examples include the Token Ring and McLEAR. Since these rings usually operate through passive activation or low-frequency transmission, their battery capacity requirements are relatively low. However, they must offer excellent voltage stability and standby performance.

3.4 Multi-Function Smart Rings

High-end rings that integrate health tracking, interaction, payment, and even GPS tracking—often designed for specialized medical or military applications. These products typically use more complex battery systems, such as dual-cell configurations or modular custom structures. They demand higher capacities (over 30mAh) and require highly customized, deeply integrated battery solutions from experienced suppliers.

Ring Type	Key Functions	Battery Capacity Range	Battery Technology Focus
Health Monitoring	Heart rate, sleep, stress, body temperature	15–30mAh	High energy density, strong thermal stability
Notification & Control	Bluetooth alerts, vibration, touch sensing	10–20mAh	Fast charging support, optimized for BLE
Payment & Security	NFC, identity verification, unlocking	5–15mAh	Excellent standby performance, voltage stability
Multi-Function Hybrid	Combination of all above functions	25–40mAh+	Fully customized, complex packaging required

4、Why Are Curved Lithium Polymer Batteries the Best Choice for Smart Rings?

Among all battery chemistries, lithium-ion polymer (Li-Po) batteries—especially the curved variants—are widely recognized as the ideal solution for smart rings and other compact wearable devices. These batteries are not only small and flexible in structure, but also capable of delivering stable and powerful energy within extremely limited space. Here are the five key reasons they have become the top choice:

4.1 High Energy Density for Multi-Functionality

Curved Li-Po batteries offer exceptionally high energy density, reaching up to 650Wh/L. They can store sufficient power in a space smaller than 1cm³, allowing smart rings to operate continuously for several days. This is especially important for rings equipped with multiple functions like heart rate monitoring, Bluetooth communication, and vibration feedback. Higher energy density means longer battery life, fewer charging cycles, and an overall better user experience.

4.2 Bendable Structure for Custom Fit

Unlike rigid batteries, curved Li-Po batteries use soft-pack construction that allows them to bend and conform to the inner arc of a ring. This enables millimeter-level space optimization, allowing the battery to fit seamlessly within the curved structure of the smart ring and maximize internal space usage.

4.3 Ultra-Lightweight for All-Day Comfort

These batteries are extremely lightweight—typically just a few grams or less—adding virtually no burden to the user. For a device designed to be worn all day, a lighter battery significantly enhances wearing comfort and reduces any sense of pressure on the finger.

4.4 Excellent Safety for Skin Contact

Polymer batteries incorporate multiple safety features—such as advanced separators, thermal protection, and overcharge/discharge safeguards—to minimize risks of leakage, swelling, or overheating. Given that smart rings are worn in direct contact with the skin, their safety standards must exceed those of typical consumer electronics. Curved batteries inherently offer better material safety and sealing technologies, making them more suitable for long-term skin contact.

4.5 Fully Customizable to Fit Diverse Applications

Whether for a simple 5mAh NFC authentication ring or a 40mAh advanced health monitoring ring, curved Li-Po batteries can be customized in terms of size, thickness, capacity, voltage, and connector layout to meet specific design needs. This level of customizability is essential for the successful commercialization of smart ring products with varying functional requirements.

5、Three Core Advantages of Choosing IRAYENERGY as Your Smart Ring Battery Supplier

5.1 Advanced Materials, Refined Craftsmanship, and Superior Performance

IRAYENERGY specializes in the development and manufacturing of high-performance batteries for smart devices, with particular expertise in curved battery materials and production processes. We utilize top-grade materials and cutting-edge technologies to deliver batteries with high capacity, stable power output, and outstanding cycle life.

Electrode Materials Tailored for Performance:
The cathode uses high-capacity lithium cobalt oxide materials, selected according to specific needs such as high discharge rates, thermal stability, or extended cycle life. The anode is made from specially formulated artificial graphite with optimized particle size and surface coating, supporting fast charging and high energy density.
High-Safety Separators for Enhanced Reliability:
Our batteries incorporate advanced separators treated with PVDF coatings, ceramic nanocoatings, and other high-performance technologies to improve thermal stability, prevent short circuits, and reduce capacity fade.
Customizable Electrolyte Systems:
Electrolyte formulations are tailored to different applications, with functional additives that improve separator durability, suppress metal dissolution, and enhance oxidation resistance.
Precision Stacking and Seamless Edge Sealing:
All curved batteries are produced using high-precision stacking and wrinkle-free thermal sealing processes, ensuring tight encapsulation and smooth edges. This prevents early-stage short circuits, internal punctures, and performance degradation, while supporting fast charge/discharge and high-voltage applications.

5.2 Integrated Supply Chain for Rapid Market Response

With over a decade of experience in lithium battery manufacturing, IRAYENERGY has established a fully integrated and highly efficient vertical supply chain. From materials sourcing and product design to delivery, every step is under strict control. We support flexible customization, rapid prototyping, small-batch verification, and stable mass production, helping customers stay ahead in the fast-paced wearable tech market.

In-house manufacturing with automated equipment
Strict quality control and global certifications
Fast delivery and agile production scheduling

5.3 Direct Factory Supply with Competitive Pricing

As a key supplier of lithium batteries for smart wearables, IRAYENERGY leverages direct factory supply and large-scale production to offer highly competitive pricing—without compromising quality. This allows us to deliver reliable, high-performance curved batteries at excellent value for a wide range of smart ring applications.

6、What Are the Charging Methods for Smart Ring Batteries?

Currently, there are several mainstream charging methods available for smart ring batteries. Each method is suited to different product designs and usage scenarios:

1) Magnetic Charging
How it works: Magnetic charging is one of the most common methods used in smart rings. It transfers power through contact points on the inner surface of the ring via a magnetic charging dock or pad.
Advantages: Simple and convenient—just align the ring with the magnetic dock, and it automatically snaps into place for stable charging.
Considerations: Proper alignment between the ring and charging contacts is essential. Misalignment may result in poor contact or incomplete charging.

2) Wireless (Inductive) Charging
How it works: Also known as inductive charging (e.g., Qi standard), this method transfers power wirelessly through electromagnetic induction from a charging pad to the ring battery, without any physical contact.
Advantages: Fully contactless charging eliminates wear and tear from repeated plugging. Just place the ring on the pad to start charging automatically.
Considerations: Not all smart rings support Qi wireless charging. Check for compatibility before use. Proper placement is also necessary to ensure efficient charging.

3) USB Dock or Stand-Based Charging
How it works: Some smart rings come with a dedicated USB charging dock or cradle that connects to a USB power source such as a laptop or power bank. The ring sits securely in the dock during charging.
Advantages: Compact and widely compatible, this method is travel-friendly and ideal for desk use.
Considerations: It is recommended to use the original charging base provided by the manufacturer to ensure electrical compatibility and optimal performance.

4) Portable Charging Case
How it works: Similar to TWS earbuds, some smart rings come with a portable charging case. The ring charges via contact points inside the case, which contains its own battery and can recharge the ring multiple times.
Advantages: Ideal for travel and short trips, allowing you to charge the ring on the go without external power sources.
Considerations: Make sure the case itself is charged in advance. Charging may be slower than with direct cable methods.

5) Direct Pin Contact Charging
How it works: Some smart rings feature small charging pins that connect directly to a specialized cable, delivering power through physical contact with internal metal terminals.
Advantages: High charging efficiency, fast power delivery, and a firm connection reduce the risk of power loss due to magnetic misalignment or wireless interference.
Considerations: Avoid bending, impacting, or corroding the charging pins to maintain long-term charging reliability.

6) Solar or Kinetic Charging (Emerging Technologies)
How it works: Some manufacturers are exploring green energy options such as solar or kinetic charging. Solar rings charge via sunlight through photovoltaic panels, while kinetic rings generate power from movement.
Advantages: These technologies allow for passive, continuous charging without cables or docks, potentially achieving “zero-intervention” energy replenishment.
Considerations: These solutions are still in the experimental or conceptual stage. Power output is limited and may not fully support all smart ring features. They are best used as supplemental power sources for now.

7、Smart Ring Battery Maintenance Tips

To ensure your smart ring battery maintains optimal performance and achieves a longer lifespan, proper maintenance is essential. Below are six key recommendations to help you manage battery health effectively during daily use:

1) Avoid Extreme Temperature Environments

Keep your smart ring away from high heat or freezing temperatures. Excessive heat can accelerate battery aging and potentially cause swelling or safety hazards, while extreme cold reduces battery efficiency and shortens runtime. It’s best to use and store the ring within a temperature range of 0°C to 45°C.

2) Maintain a Regular Charging Routine

Avoid waiting until the battery is completely drained before charging. It is recommended to recharge when the battery level drops to around 20%. This helps slow down battery degradation and extends cycle life. Try to avoid prolonged overcharging or letting the battery drop to 0%.

3) Clean the Device Regularly

Dust, sweat, and debris may accumulate on the battery contacts or charging interface, which can affect power transfer and charging efficiency. Use a soft, dry cloth to clean the ring regularly, especially after frequent use or workouts.

4) Follow Manufacturer Guidelines

Always refer to the user manual provided by the manufacturer. These guidelines include proper charging methods, usage restrictions, and storage recommendations tailored to your specific device model. Adhering to them helps prevent damage due to improper handling.

5) Keep Firmware Up to Date

Manufacturers occasionally release software or firmware updates to optimize battery management, fix excessive power consumption bugs, and improve overall battery life. Check periodically for available OTA updates and install them under a stable Wi-Fi connection.

6) Store Unused Devices Properly

If you’re not using the smart ring for an extended period, charge the battery to around 50% before storing it in a cool, dry place. Avoid full depletion during storage, which could lead to deep discharge failure. Check the battery level every 3 months and recharge as needed to maintain battery activity.

FAQs About Smart Ring Battery

Can the battery in a smart ring be replaced?

Most smart rings use a built-in battery design and are not intended for user replacement. If a replacement is needed, it is recommended to contact the original manufacturer or a professional service provider to ensure safety is not compromised.

How long does a full charge last?

Battery life depends on the battery capacity and how intensively the ring is used. Generally, a 10–30mAh lithium battery can support continuous use for 2–5 days. Rings with features like health monitoring and Bluetooth tend to have shorter battery life.

How long does it take to charge?

Smart rings that support fast charging can typically reach 80% in about 30 minutes. A full charge may take 60–90 minutes, depending on the charging method and battery capacity.

How can I extend the lifespan of my smart ring battery?

Maintain the battery charge between 20% and 80%; avoid deep discharge or prolonged overcharging. Regularly clean the charging contacts and keep the device away from high temperatures or humid conditions. If not used for an extended period, store the ring with the battery charged to around 50%.

Is a larger battery capacity always better?

While larger capacity generally means longer battery life, it may also increase the size and weight of the ring. It’s important to strike a balance between functionality and wearing comfort. Some high-end models use customized battery structures to optimize space.

Do smart ring batteries support fast charging?

Some brands support fast charging, allowing the battery to reach 70%–80% in 15–30 minutes, but this typically requires a dedicated fast-charging dock or adapter. Whether a specific ring supports fast charging depends on the product specifications.

Do smart ring batteries need calibration or activation?

Modern lithium batteries are pre-activated at the factory and require no manual activation by the user. For best results, fully charge the battery before first use and maintain regular charging cycles—no additional calibration is necessary.

📌 Tip:
For professional Smart Ring Battery customization or replacement solutions, feel free to contact the IrayEnergy engineering team. We’re here to provide efficient, reliable, and high-performance power solutions!