Industry Background: Why Power Matters for Portable Card Readers

Portable card readers have become indispensable in modern commercial and industrial operations. From retail checkout and
transportation ticketing to handheld payment terminals, logistics scanning, and mobile identity verification, these devices
are at the center of everyday transactions.

A typical portable card reader integrates NFC/RFID modules, secure encryption chips, wireless communication (Bluetooth,
Wi-Fi, 4G/5G), and compact displays. All of these subsystems demand a stable, high-density power source in a very limited
space. Among all available battery technologies, the cylindrical 18650 lithium-ion cell remains one of the
most reliable and widely adopted choices for OEM card reader designs.

For device brands that need differentiated performance or special size/configuration, a

custom Li-ion polymer battery solution

or cylindrical 18650 pack design is often required to perfectly match internal structure, runtime, and certification targets.

Key Power Pain Points in Portable Card Readers

Battery design for portable card readers is not just about capacity. It must also address several critical pain points that
directly affect user experience, transaction reliability, and device lifetime.

1. High Peak Current During Card Reading & Data Transmission
   When the reader performs card authentication, encryption, wireless data transmission, or prints receipts (for some models),
   the system experiences short but sharp current spikes. The battery must support these peaks without voltage drop that can
   cause communication errors or system resets.
2. Long Standby with Instant Activation
   Many handheld terminals remain in low-power standby mode for long periods and must instantly wake up to process
   transactions. Low self-discharge and excellent standby performance are therefore essential.
3. Limited Internal Space
   Designers must integrate the battery with PCB, wireless modules, antenna, keys, and display in a highly compact enclosure.
   The battery pack must be slim, safe, and easy to fix inside the housing.
4. High-Frequency Usage Requirements
   In retail peak hours or busy public transportation environments, devices may process hundreds or thousands of transactions
   per day. The battery must support frequent charge/discharge cycles with reliable performance over its service life.
5. Strict Safety Requirements for Encrypted/Financial Devices
   Card readers belong to security-sensitive equipment. Any abnormal power behavior may cause data loss, transaction failure,
   or even security risks. High-reliability cells plus a robust protection circuit are mandatory.

Why 18650 Lithium Batteries Are an Ideal Choice

The 18650 lithium-ion cell has matured over many years of development and is widely used in tools, industrial devices,
and portable electronics. For portable card readers, it offers a combination of performance, safety, and cost that is
difficult to beat.

• High Energy Density
  Typical capacities range from 2400–3500 mAh per cell, allowing compact packs with sufficient runtime for
  a full work shift.
• Stable Discharge Curve for Peak Loads
  A flat discharge curve helps keep system voltage stable during wireless bursts, card reading, and printing.
• Long Cycle Life
  NMC/NCA chemistries commonly achieve 800–1500 cycles, while
  
  LiFePO₄ battery customization
  
  can exceed 2000+ cycles where ultra-long life is required.
• Strong Safety Characteristics with BMS Protection
  When combined with a professional PCM/BMS (OVP, UVP, OCP, SCP, NTC), 18650 packs deliver safe and predictable performance
  for financial and security applications.
• Flexible Customization for OEM Integration
  1S or multi-cell 18650 configurations can be arranged in different layouts, with customized harness, connectors, and
  mechanical design to fit each card reader platform.

Technical Insights: How 18650 Packs Support Real-World Operation

Beyond cell selection, professional power system design ensures that the card reader operates stably in real-world scenarios.
Key technical characteristics include:

• Low Self-Discharge for Long Standby
  18650 lithium cells exhibit low self-discharge, which helps devices remain in standby for long periods while still waking up
  reliably to process transactions.
• Flat Voltage Output
  A relatively flat voltage curve during discharge means that RF modules, secure processors, and displays receive stable
  voltage, lowering the risk of communication errors.
• Multiple Chemistry Options
  Depending on priorities (high energy, high power, or ultra-long life), customers can choose from NMC/NCA, LiFePO₄,
  or high-drain 18650 cells.
• Optional PCM/BMS with Multi-Level Protection
  Protection features can include OVP, UVP, OCP, SCP, NTC temperature monitoring, and communication functions where required.
• Optimized Thermal Performance
  Packs are typically designed to operate in 0–50 °C environments, with proper material selection and
  mechanical design to support higher reliability.

For industrial handhelds, portable testers, or detection devices with higher power consumption, PKNERGY also offers
dedicated

Portable Detection Device Power Solutions

based on 18650 and other chemistries.

Typical Application Scenarios

18650-based battery packs are widely used in different types of portable card readers and terminal devices:

• Retail Mobile POS Systems
  Handheld payment terminals in shops, supermarkets, and restaurants require long runtime and stable wireless communication
  throughout a whole day.
• Public Transportation Ticketing Terminals
  Ticket inspectors and on-board card readers must handle high-frequency tap-in/tap-out transactions with reliable power.
• Logistics Scanning & Warehouse Devices
  Portable scanners for parcel tracking or warehouse management rely on robust batteries to support continuous scanning and
  wireless data upload.
• Event Ticketing & Access Control
  Temporary or mobile access control systems for events, concerts, and exhibitions rely on handheld devices that need secure
  and safe power sources.
• Government & Security Identity Verification Tools
  ID readers and verification terminals often use secure, customized battery packs that comply with strict safety and
  reliability standards.

Many of these devices are part of broader
Security Devices Power Solutions and

Consumer Electronics Power Solutions
, where PKNERGY can design unified battery platforms for multiple product lines.

PKNERGY 18650 Custom Pack Solutions for Card Readers

As a professional custom battery pack manufacturer, PKNERGY provides tailored 18650 battery solutions for portable card
readers and other handheld payment or scanning devices.

Our services include:

• Cell Selection & Pack Design
  Selecting the most suitable 18650 cells (NMC/NCA or LiFePO₄) based on your runtime, size, and lifetime
  requirements.
• Customized PCM/BMS Design
  Protection and, if needed, communication functions tailored to your system voltage, current, and safety requirements.
• Mechanical & Connector Engineering
  Pack structure, fixing points, harness, and connector selection designed to fit your internal layout and assembly process.
• Certification Support
  Support for UN38.3, IEC, CE and other certifications required for transportation and market access.
• Flexible OEM/ODM Cooperation
  From sample development to mass production, PKNERGY can work closely with your R&D and procurement teams to shorten
  project lead time.

Whether you need a classic 18650 pack or a more compact

custom Li-ion polymer battery

for ultra-slim card readers, PKNERGY can design and manufacture a power solution that fits your device perfectly.

If your roadmap also includes emerging chemistries, such as

custom sodium-ion battery solutions
, our engineering team can help evaluate feasibility and plan a technology transition path.

FAQ: Portable Card Reader Battery Design

For more general questions about PKNERGY’s custom battery capability, you can also visit our
FAQ center.