3.7V 4000mAh 18650 Battery Pack

3.7V 4000mAh 18650 Battery Pack for Sound Box

In the new era, smart speaker manufacturers demand more from batteries than just basic functionality—they require enhanced safety, lighter weight, and longer lifespan.

CM Batteries offer a protected 3.7V 4000mAh 18650 li ion Battery Pack, delivering reliable performance, a compact design, and stable output supporting 2A continuous and 4A peak discharge for consistent audio quality and extended operation. It also comes with standard interfaces and customizable options to accelerate development and streamline production.

3.6V 2000mAh Rechargeable High Temperature Battery Pack

Key features:

  • Integrated with PCB protections,discharge current 2A and Peak discharge current 4A
  • Configuration: 1S1P,made of highest capacity 1pcs 3.6V 18650 4000mAh rechargeable cell
  • Connector: XH 2.54 with 150mm ,custom connectors are available upon request.
  • Dimension: 19*69.5(mm) and Weight: 50g
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3.7V 4000mAh 18650 Battery Pack Parameter

No. Item Parameter Remark
1 Nominal Voltage 3.7V 3.6V/Cell
2 Nominal Capacity 4000mAh @0.2C
3 Minimum Capacity 3850mAh
4 Shipment Voltage /
5 Initial Internal Impedance ≤80mΩ AC 1KHZ
6 Standard Charge Voltage 4.2V 4.2V/Cell
7 Standard Charge Current 2A
8 Max. Charge Current 4A
9 Standard Discharge Current 2A
10 Max. Discharge Current 4A
11 Burst Discharge Curren 8A ≤5s
12 Discharge Cut-off Voltage 2.5V 2.7V/Cell
13 Cycle Life ≥500 cycles Retention: ≥70%
14 Charge Temperature 0°C~+45°C Standard Charge
15 Discharge Temperature -20°C ~+60°C Standard Discharge
16 Storage Temperature -20°C~ +45°C ≤3 Months
-20°C~ +25°C ≤1 Year
17 Weight About 50 g
18 Special Request

3.7V 4000mAh 18650 Battery Pack FAQs

Can this battery pack be adapted to my existing sound box design?

Yes. We provide flexible connector options, wire lengths, and pack designs to match your assembly requirements and reduce redesign costs.

How do you ensure product consistency in bulk production?

All packs are manufactured with strict quality control and testing, including internal resistance, capacity, and safety checks, to guarantee uniform performance.

Do you provide testing and certification services?

Yes. We offer customization based on your specific requirements, including waterproof designs, heating functions, and low-temperature operation (as low as -20°C). We also provide custom BMS configurations and communication protocols such as CAN, SMBus, and RS485 to ensure compatibility with demanding or outdoor environments.

Is it possible to produce samples or in small quantities?

Yes. We provide a flexible MOQ, which includes small-batch customization and sample orders for prototype testing.

Are other capacity options available for this battery pack?

Certainly. This battery pack is built with a single 18650 cell and is available in capacities of 2000mAh, 2600mAh, 2900mAh, 3500mAh, or 4000mAh.

Tailored Customization

Our design team can create custom battery designs for just about any device or machine.

Timely Delivery

Our efficient production and distribution process gets your product delivered in a timely manner.

Quality Guarantee

We stand by our products and guarantee you’ll be happy with your purchase.