Samsung 40T 4000mAh 40A 21700 Li-Ion Cell – High Drain

The Samsung 40T 4000mAh is a high drain (high current) 21700 lithium-ion cell built for battery pack assembly and repair. It is used in electric motorcycle packs such as Sur-Ron Light Bee and Talaria class machines. In addition, it suits electric scooters, e-bikes and power tool packs that demand sudden current delivery.

Each cell holds 4000 mAh and delivers a maximum discharge current of 40 A. The nominal voltage is 3.6 V, while the charge limit sits at 4.2 V. The cut-off voltage is 2.5 V. Dimensions follow the 21700 standard: 21 mm diameter and 70 mm length. Weight is approximately 67 g per cell.

The terminal is flat, so the cell accepts spot welding with nickel strip. Chemistry is Li-ion and the cell is rechargeable. Importantly, this is an unprotected cell with no protection circuit. Therefore, any pack you build requires a BMS to control charge and discharge limits.

Key Benefits

• 40 A maximum discharge current — the cell handles heavy loads when a motor demands instant power.
• 4000 mAh capacity — single-cell energy that adds up across parallel (P) groups into total pack capacity.
• 21700 format — 21 mm diameter and 70 mm length let you plan pack geometry without adapters.
• Approximately 67 g weight — pack mass can be calculated precisely during the design stage.
• 3.6 V nominal voltage — the standard Li-ion figure used to calculate series (S) group voltage.
• Flat terminal — convenient for spot welding with nickel strips.
• Defined voltage limits — 4.2 V upper charge limit and 2.5 V cut-off voltage.
• Samsung SDI production — from the Samsung group division that manufactures cylindrical cells.

Who Is This Cell For?

This cell suits builders who assemble or repair battery packs themselves. First of all, that means electric motorcycles — Sur-Ron Light Bee and Talaria class machines whose packs need high current cells. It is equally used in electric scooters and electric bicycles.

Beyond two-wheelers, the Samsung 40T fits power tools, where the motor briefly demands a large current surge. Consequently, the cell is popular in high power DIY projects and mod devices. This product is aimed at battery manufacturing specialists and experienced builders. A single cell is not a finished battery. Do not fit it directly into a device that requires a protected battery.

Technical Specifications

Why Choose the Samsung 40T?

The main difference here is 40 A discharge current alongside 4000 mAh capacity. Many ordinary 21700 cells focus on capacity alone, so they cannot sustain large currents. The Samsung 40T combines both parameters in one 21 × 70 mm body.

Compared with 18650 format cells, the 21700 body has more internal volume. As a result, a pack needs fewer cells to reach the same capacity. The number of joints and weld points drops too. Meanwhile, the precise ~67 g figure lets you calculate total pack mass in advance — useful when designing electric motorcycle packs, where weight directly affects riding dynamics.

Frequently Asked Questions

What is the capacity of the Samsung 40T 4000mAh?

• Capacity is 4000 mAh per cell.
• That figure applies to one cell, not to a finished pack.
• Capacity adds up across parallel (P) connected groups.

What is the maximum discharge current?

• The maximum discharge current is 40 A.
• This rating suits loads with sudden power demand.

Is the Samsung 40T suitable for Sur-Ron and Talaria packs?

• Yes, it is used in Sur-Ron Light Bee and Talaria class electric motorcycle packs.
• These machines need high current cells.

Can I use this cell in an electric scooter or e-bike?

• Yes, the cell is used in scooter and bicycle battery packs.
• It also works in power tool packs and DIY builds.

Does the cell have a protection circuit?

• No, this is an unprotected cell.
• A BMS is required to control charge and discharge limits.

What are the voltage limits?

• Nominal voltage is 3.6 V.
• The charge limit is 4.2 V and the cut-off is 2.5 V.

Can the cell be spot welded?

• Yes, the terminal is flat.
• That shape suits spot welding with nickel strip.

What are the dimensions and weight?

• Diameter is 21 mm and length is 70 mm.
• Weight is approximately 67 g.

The Samsung 40T 4000mAh is a rechargeable Li-ion cell from Samsung SDI, supplied for pack building rather than direct device use. Plan your series and parallel layout around 3.6 V and 4000 mAh, then pair the finished pack with a suitable BMS.