If you are a complete novice and have just started using 18650 batteries to power your project, the simplest way is to use ready-made modules that can safely charge and discharge your 18650 batteries. Only the TP4056 module can handle a single 18650 battery.

If your project requires an input voltage of 3.6V or higher, you may want to connect two 18650 batteries in series to obtain a voltage of 7.4V. In this case, using modules such as the 2S3A lithium-ion battery module should help with safe charging and discharging of the battery.

To combine two or more 18650 batteries, we cannot use traditional welding techniques to connect the two, but instead use a method called spot welding. In addition, more caution should be exercised when combining 18650 batteries in series or parallel, as will be discussed in the next paragraph.

Shenzhen Topband Battery Co., Ltd.，established in 2006, is a wholly-owned subsidiary of Shenzhen Topband Co., Ltd. (002139.SZ). We focus on lithium iron phosphate batteries,with independent research and development in cells and BMS. With the ability to integrate the entire industry chain, we are committed to providing customers with one-stop lithium battery solutions and services. Our quality products are widely used in energy storage and light power.