Samsung INR21700-40T 4000mAh 35A Li-ion Battery for Power Tools, E-Bikes & DIY Battery Packs (1-100 PCS)

The Samsung INR21700-40T 4000mAh 35A Continuous Discharge Li-ion Rechargeable Battery (40T / 40T5) is an elite high-drain 21700 cylindrical power cell engineered for demanding high-current applications. Manufactured by Samsung SDI and supplied by DXF POWER with strict quality grading, this flat-top unprotected cell delivers a minimum 4000mAh standard capacity at 3.6V nominal platform (4.20V max charge) with an impressive 35A continuous discharge rating without temperature cut (up to 45A with an 80°C thermal cut-off). It is the premier choice for high-draw cordless power tools, electric skateboards, e-bikes, scooters, high-lumen flashlights, and custom multi-cell DIY battery packs requiring massive current delivery and robust cycle life.

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Key Features

• Genuine Samsung SDI 40T Cell: Authentic Grade-A 21700 cylindrical cell (40T / 40T5) renowned for low internal resistance and massive continuous power delivery
• 35A Continuous Discharge Rating: Delivers true 35A continuous discharge without temperature cutoff (and up to 45A with 80°C surface thermal control)
• 4000mAh High Capacity: Minimum 4000mAh standard discharge capacity (at 0.2C / 800mA) and minimum 3900mAh rated capacity at 10A discharge
• High-Speed Rated Charging: Supports 2A standard charge (approx. 180 mins) and rapid 6A rated charging (approx. 70 mins to full charge)
• Robust Cycle Life & Storage Recovery: Retains ≥2400mAh after 250 harsh cycles (6A charge / 35A discharge at 25°C), and ≥3510mAh recovery after 30 days storage at 60°C
• Standard 21700 Flat-Top Design: Dimensions (21.22mm max diameter × 70.30mm max height) with flat top terminal, ideal for spot-welded packs and modular battery sleds
• Multiple Pack Bundles: Available in 1, 10, 20, 50, and 100 piece packages to suit single replacements or bulk pack fabrication

Specifications, Per Battery

• Brand / Manufacturer: Samsung SDI (Supplied by DXF POWER)
• Model / Variant: INR21700-40T (40T / 40T5)
• Cell Type: 21700 Cylindrical Rechargeable Lithium-ion (Li-ion)
• Positive Terminal / Form Factor: Flat Top (Unprotected industrial cell)
• Standard Discharge Capacity: Minimum 4000mAh (at 0.2C / 800mA discharge to 2.5V)
• Rated Discharge Capacity: Minimum 3900mAh (at 10A discharge to 2.5V)
• Nominal Voltage: 3.6V
• Charge Cut-Off Voltage: 4.20V
• Discharge Cut-Off Voltage: 2.50V (end-of-discharge)
• Continuous Discharge Current: 35A (without temperature cut, recommended headline rating); 45A with 80°C surface thermal control
• Standard Charge: CC-CV, 2A, 4.20V, 200mA cut-off (approx. 180 minutes)
• Rated Fast Charge: CC-CV, 6A, 4.20V, 100mA cut-off (approx. 70 minutes)
• Cycle-Life Criterion: ≥2400mAh after 250 cycles (6A charge, 35A discharge to 2.5V at 25°C)
• Storage Recovery: ≥3510mAh after 30 days at 60°C
• Ambient Operating Temperature: Charge: 0°C to 45°C / Discharge: -20°C to 60°C
• Surface Temperature Limits: Charge: 0°C to 50°C / Discharge: -20°C to 80°C (recommended re-discharge release <60°C)
• Dimensions: 21.22mm max diameter × 70.30mm max height (with tube)
• Weight: 70.0g max (approx. 67g nominal)
• Protection: No integrated protection circuit (requires device-level or pack BMS protection)
• Applications: Cordless power tools, electric bicycles, e-scooters, electric skateboards, high-output flashlights, robotics, and custom DIY battery packs

Package Includes

• Samsung INR21700-40T 4000mAh 35A battery cells, quantity chosen from 1, 10, 20, 50, or 100 PCS
• Protective packaging / cell box
• User manual and battery safety guide

Choose Your Ideal Power Bundle

• 1 PCS – Quick Replacement & Testing: Single cell for flashlight upgrade, tool testing, or individual cell repair
• 10 PCS – Tool Pack Rebuilds: Perfect for rebuilding heavy-duty cordless power tool battery packs
• 20 PCS – High-Output Modules: Ideal for 36V or 48V auxiliary modules, robotics, and DIY power packs
• 50 PCS – Mobility & Energy Modules: Tailored for high-performance electric bike packs, e-scooters, and portable power stations
• 100 PCS – Master Builder Bulk Set: Best value for workshops, custom pack assemblers, and volume battery builders

Purchasing in bundles ensures matched cell batches for balanced series and parallel assembly.

180-Day Warranty & Customer Support

Every cell batch supplied by DXF POWER is covered by a 180-day manufacturer warranty against defects in materials and craftsmanship. Our technical support team is always available to assist with charging parameters, pack layout recommendations, and safety practices.

Usage & Safety Guidelines

• Use a dedicated lithium-ion smart charger supporting CC/CV charging mode.
• Never charge above 4.20V per cell or discharge below 2.50V per cell.
• Do not exceed cell surface temperature of 50°C during charging and 80°C during discharge; allow cell to cool below 60°C before recharging.
• Always inspect cell outer shrink wrap, insulator ring, and terminals for damage before use; rewrap immediately if damaged.
• Never carry loose 21700 batteries in pockets, bags, or purses with metal objects like keys or coins; always store in an insulated battery case.
• Do not short-circuit, crush, incinerate, puncture, or submerge cells in water.
• Store batteries at 3.60V–3.85V per cell in a cool, dry, well-ventilated location away from direct sunlight.
• When building multi-cell packs, always integrate a quality Battery Management System (BMS) with over-current, over-charge, over-discharge, and thermal balance protection.

Why Choose DXF?

• Genuine Grade-A Samsung SDI 40T cells with true 4000mAh capacity and tested 35A high-drain output
• Reliable 35A continuous discharge rating under demanding industrial operational loads
• Carefully matched batches for balanced series and parallel pack assembly
• Strict factory pre-shipment quality checks and secure protective packaging
• Global warehouse logistics network and professional technical customer support

Perfect For

Engineered for contractors, e-mobility builders, DIY pack fabricators, and enthusiasts demanding class-leading 35A continuous output and 4000mAh capacity for high-drain cordless tools, electric transport, robotics, and custom energy modules.

Power your projects with trusted Samsung 21700 performance. Learn more about setups and battery care on the DXF YouTube channel.