26650 Low-Temperature LFP Cell 3500mAh 4-Pack

$39.00

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ISO 9001:2025/IATF 16949 traceable 26650 LFP cells, 3500mAh, 3.2V, charge to -20°C and discharge to -40°C for cold-region packs; 4-pack. Order now.

Description

3500mAh Ultra-Low-Temperature 26650 Lithium Iron Phosphate (LFP) Cylindrical Battery (4-Pack)

COMMERCIAL GRADE · PRODUCTION

Product Overview

The ATOMFAIR® 26650 Low-Temperature LFP (LiFePO4) cylindrical cell is engineered for extreme cold-weather energy storage applications. With a nominal capacity of 3500mAh and the unique ability to charge and discharge at temperatures as low as -20°C without external heating, this cell eliminates the need for battery warmers in winter environments. Offering high energy density (128Wh/kg), military-grade reliability, and civilian-friendly pricing, it is the ideal choice for off-grid solar storage, EV auxiliary batteries, cold-region telecom backup, and polar research equipment. For bulk inquiries or official volume quotations, please contact us via email at inquiry@atomfair.com.

Technical Specifications

PARAMETER VALUE
General Parameters
Nominal Capacity (0.2C) 3500 mAh
Minimum Capacity (0.2C) 3450 mAh
Nominal Voltage 3.2 V
Energy Density 128 Wh/kg
Internal Resistance ≤25 mΩ
Weight ≈87 g
Cycle Life (80% DOD, 25°C) 1500 cycles
Charge Parameters
Max. Charge Voltage 3.65 ± 0.03 V
Standard Charge Current 0.5C
Max. Charge Current 1.0C @ T>0°C; 0.5C @ T≤0°C; 0.2C @ T≤-10°C
Discharge Parameters
Min. Discharge Voltage 2.00 V @ T > -20°C; 1.50 V @ T ≤ -20°C
Standard Discharge Current 0.5C
Max. Continuous Discharge Current 1.0C (module level)
Discharge Performance >70% @ -40°C to 1.5V; >75% @ -20°C to 1.5V; >98% @ 60°C to 1.5V
Temperature Ranges
Charge Temperature -20°C to 55°C
Discharge Temperature -40°C to 60°C
Manufacturing Compliance: Fully traceable production under ISO 9001:2025 and IATF 16949 standards. Custom form factors or electrode formulations available upon request.

Key Features & Advantages

  • Direct Charge & Discharge at Sub-Zero Temperatures: No pre-heating required — capable of charging at temperatures as low as -20°C.
  • Excellent Low-Temperature Power Output: Supports continuous 1C discharge below 0°C with >90% discharge efficiency.
  • High Energy Density for Cold Storage Markets: 128Wh/kg enables compact, lightweight battery packs for harsh environments.
  • Military-Grade Reliability at Civilian Prices: Extreme durability and robust cycle life (1500 cycles @ 80% DOD) without premium cost.

APPLICATION SCOPE: Off-grid solar storage in cold regions, EV auxiliary batteries, telecom backup in northern climates, polar research equipment, cold-chain logistics, and portable power for winter sports.
PACKAGING: Anti-static plastic trays (50 cells per tray, 200 cells per master carton). Insulated terminal covers included for safe transport.
IMPORTANT NOTICE: For charging at -20°C, use the recommended CC-CV profile with a reduced charge current (≤0.2C). The cell will not accept charge below -20°C. Always pair with a low-temperature BMS that enables charging only when cell temperature is within safe limits.

TAILORED SOLUTIONS FOR RESEARCH
Contact our engineering team for technical support or official institutional quotations.
EMAIL: inquiry@atomfair.com
Manufacturer: Atomfair LLC
Brand: ATOMFAIR®

This cell must be charged within -20°C to 55°C and discharged within -40°C to 60°C. A low-temperature BMS is required to prevent charging below safe temperature limits.

  • Charge Voltage Limit: The maximum charge voltage must not exceed 3.65±0.03V to prevent overcharge degradation.
  • Discharge Voltage Limit: The minimum discharge voltage is 2.00V above -20°C and 1.50V at or below -20°C to avoid irreversible capacity loss.
  • Temperature-Dependent Charge Current: The charge current must be reduced to 0.2C at -20°C and 0.5C at temperatures between -10°C and 0°C to ensure safe operation.
  • Storage and Transport: Cells must be stored in anti-static trays with insulated terminal covers to prevent short circuits and mechanical damage.
  • BMS Integration: A low-temperature BMS must enable charging only when the cell temperature is within the safe charge range.

Follow these steps to initialize and safely charge the battery pack at sub-zero temperatures. Proper setup ensures optimal performance and prevents damage.

Required Equipment: Low-temperature BMS, CC-CV charger

  1. Inspect Packaging
    Inspect the packaging and verify that terminal insulation covers are intact.
  2. Connect BMS
    Connect the cell pack to a low-temperature BMS that disables charging below -20°C.
  3. Set Charger Profile
    Set the charger to a CC-CV profile with a maximum charge current of 0.2C at -20°C.
  4. Confirm Temperature
    Confirm that the cell temperature is above -20°C before initiating the charge cycle.
  5. Monitor Voltage
    Monitor the charge voltage to ensure it does not exceed 3.65V during the constant-voltage phase.

Why does the minimum discharge voltage change from 2.00V to 1.50V when operating below -20°C?

At temperatures of -20°C or lower, increased internal resistance causes a higher voltage drop under load, requiring a lower cutoff voltage to extract usable capacity. The cell is rated to deliver >70% of nominal capacity at -40°C down to 1.50V, whereas above -20°C the cutoff is 2.00V to maintain standard protection thresholds. This trade-off maximizes low-temperature energy delivery without prematurely ending discharge.

What BMS specifications are critical for integrating this cell into a cold-climate energy storage system?

A low-temperature battery management system (BMS) that monitors cell temperature and prevents charging below -20°C is mandatory. The cell will not accept charge below this threshold, and forcing charge can cause irreversible damage. The BMS must also enforce the reduced charge current limits: ≤0.2C at -20°C, 0.5C between -10°C and 0°C, and 1.0C above 0°C.

What are the safe temperature limits for charging and discharging this cell, and what performance can be expected at the extremes?

Charging is allowed from -20°C to 55°C; the cell will not accept charge below -20°C. Discharging is permitted from -40°C to 60°C with >70% capacity retention at -40°C and >75% at -20°C. Exceeding these temperature limits may cause permanent capacity loss or internal damage, so a BMS that enforces these ranges is essential.

This 26650 LFP cell provides reliable operation at -20°C with direct charging capability, but requires careful current management and BMS integration for optimal performance and safety.

Positive

  • Direct sub-zero charging without pre-heat: Capable of charging at temperatures as low as -20°C without external heating, eliminating need for battery warmers in cold environments.
  • High energy density and cycle life: 128 Wh/kg energy density enables compact pack design, while 1500 cycles at 80% DOD ensures long operational life for stationary and mobile applications.

Trade-offs

  • Reduced charge current at low temperatures: Maximum charge current is limited to 0.2C at -20°C and 0.5C at ≤0°C, requiring extended charging times or lower-power profiles in cold conditions.
  • Charge temperature floor at -20°C: Cell will not accept a charge below -20°C; a low-temperature BMS monitoring cell temperature is required to prevent unsafe charging attempts.

Every advanced material, component, equipment, and instrument in our catalog is backed by rigorous testing. We maintain strict internal quality management frameworks and align with CE conformity metrics to deliver transparent, reproducible performance data via our public open-science repository.

To request raw batch performance data, submit formal vendor registration paperwork, or execute a fast-turnaround R&D manufacturing loop, contact us at inquiry@atomfair.com.

Item is dispatched under the Atomfair Shipping & Delivery Framework (Free worldwide shipping on orders over $59 USD). Return is governed by the Atomfair Return & Refund Policy (7-day technical return window).