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YFH21700-4000Mha

YFH-INR21700-40Q 4000mAh 45A 70@80C 140A 5S

Original price was: $8.38.Current price is: $5.16.

YFH-INR21700-40Q 4000mAh 45A 70@80C 140A 5S

394 in stock

SKU: YFH-INR21700-40Q 4000mAh 45A 70@80C 140A 5S Category: Tags: , , , Brand:

YFH-INR21700-40Q 4000mAh 45A 70@80C 140A 5S

YFH-INR21700-40Q 4000mAh 45A 70@80C 140A 5S. High-performance cell for demanding battery packs and DIY builds.

Technical Specifications

Model YFH-INR21700-40Q 4000mAh 45A 70@80C 140A 5S
Format 21700
Nominal Capacity 4000mAh
Discharge Current 50A
Brand YFH-INR21700-40Q

Safety Warning

Unprotected cell. Always use with a BMS. Never short-circuit or overcharge. Keep away from fire and extreme heat. Not for use in e-cigarettes or similar devices.

Cell Specification

Item Specification and comments
Model YFH-INR21700-40Q – cylindrical lithium-ion rechargeable cell
Nominal capacity 4000mAh (0.5C discharge, 4.20–2.50V)
Minimum capacity 3900mAh (0.5C discharge, 4.20–2.50V)
Nominal voltage 3.70V
Discharge cut-off voltage (min) 2.50V
Max charge voltage 4.20 ± 0.05V
Standard charging current 4A (standard charge: 4000mA CC to 4.2V, then CV at 4.2V with 100mA cut-off, 25 ± 3°C)
Max. charge current 12A
Max. continuous discharge current 45A (without temperature cut-off), 70A (with 80°C temperature cut-off)
Instantaneous discharge current 140A (5s pulse)
Internal AC impedance ≈4mΩ (without PTC), measured at 1kHz
Cell weight 67.0 ± 2.0g
Cell dimension Diameter ≈21.20 ± 0.20mm; Height 70.50 ± 0.20mm; Prohibited welding area diameter ≈4mm
Energy density (by weight) 221Wh/kg
Energy density (by volume) 595Wh/L
Operating temperature (surface) Charging 0–50°C; Discharging -20–80°C
Storage temperature 1 month: -20–60°C; 3 months: -20–45°C; 1 year: -20–25°C
Delivery voltage range 3.65–3.70V

Download Manufacturer data sheet

Battery Safety

Battery Safety & Product Disclaimer

Read before purchasing or using any rechargeable lithium-ion battery.

Rechargeable lithium-ion batteries are high-energy devices that require proper handling and technical knowledge. Improper use can lead to fire, explosion, thermal runaway, serious injury, property damage, or death.

By purchasing products from CH-AmpX, you acknowledge these risks and agree to use all battery products responsibly and in accordance with manufacturer specifications.

Read the Complete Battery Safety Guide

Is This Product Right for You?

CH-AmpX battery cells are intended for:

  • Professional battery pack builders
  • Engineers and product developers
  • Industrial applications
  • Qualified hobbyists familiar with lithium-ion battery technology

These cells are designed to be integrated into battery packs protected by an appropriate Battery Management System (BMS) or Protection Circuit Board (PCB).

They are not intended for standalone consumer use, vaping devices, e-cigarettes, or any application lacking proper battery protection.

Before Every Use

Always inspect every battery before charging, installing, or transporting it.

Do not use any battery that shows signs of:

  • Damaged or torn PVC wrapping
  • Missing insulator ring
  • Dents or crushed casing
  • Swelling or bulging
  • Leakage
  • Corrosion
  • Burn marks or overheating

Using a damaged cell significantly increases the risk of battery failure.

Safe Charging Practices

Battery safety begins with proper charging.

Always:

  • Use a charger designed for lithium-ion batteries.
  • Confirm the charger matches the battery's voltage specifications.
  • Charge on a non-flammable surface.
  • Monitor batteries while charging.

Never:

  • Overcharge or over-discharge a battery.
  • Leave batteries charging unattended.
  • Charge damaged cells.
  • Use incompatible charging equipment.

Safe Storage & Transportation

Improper storage is one of the leading causes of accidental battery incidents.

Never carry loose batteries in:

  • Pockets
  • Backpacks
  • Purses
  • Toolboxes
  • Bags containing metal objects

Contact with keys, coins, tools, or other conductive materials can create a short circuit capable of causing severe burns, fire, or explosion.

Always transport batteries inside protective, non-conductive battery cases.

Store batteries in a cool, dry environment away from excessive heat, moisture, and direct sunlight.

Understanding Thermal Runaway

Thermal runaway is a rapid chain reaction that causes a battery to generate excessive heat, potentially resulting in venting, fire, or explosion.

It may be caused by:

  • Overcharging
  • Short circuits
  • Physical damage
  • Excessive temperatures
  • Internal battery failure

Reducing these risks begins with proper charging, careful handling, and correct battery storage.

Never Do the Following

To reduce the risk of injury or property damage, never:

  • Short circuit a battery.
  • Crush, puncture, or modify the cell.
  • Expose batteries to fire, water, or excessive heat.
  • Charge or discharge outside the manufacturer's specifications.
  • Dispose of lithium-ion batteries in household trash.

Recycle batteries only through approved recycling facilities.

If a Battery Fails

Immediately stop using any battery that becomes unusually hot, swells, leaks, hisses, or emits smoke.

If it can be done safely:

  • Move the battery to a non-flammable surface such as concrete or sand.
  • Keep it away from combustible materials.
  • Allow the battery to cool from a safe distance.

For lithium-ion battery fires, an ABC dry chemical extinguisher may be used. Large amounts of water may also be effective for cooling lithium-ion cells and helping prevent fire spread. Continue monitoring the battery after the incident, as damaged cells may reignite.

If the fire cannot be safely controlled, evacuate the area immediately and contact emergency services.

CH-AmpX Product Disclaimer

CH-AmpX supplies lithium-ion batteries and battery components intended for knowledgeable users and professional battery pack builders.

Customers are responsible for ensuring that all batteries are used, charged, stored, transported, and installed according to manufacturer specifications, industry best practices, and applicable regulations.

CH-AmpX shall not be held liable for any injury, property damage, equipment failure, financial loss, or other damages resulting from:

  • Improper handling or misuse
  • Incorrect charging practices
  • Unauthorized modification
  • Improper storage or transportation
  • Failure to follow recommended safety procedures
  • Use outside manufacturer specifications

By purchasing from CH-AmpX, you acknowledge the inherent risks associated with lithium-ion batteries and accept full responsibility for their safe handling and use.

View Complete Safety Guide
Weight 0.15 lbs
Dimensions 2.776 × 0.835 × 0.835 in

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