32650 and 32700 are both lithium-ion battery cell sizes known for their larger physical dimensions and higher capacity. Here are some reasons why these batteries are preferred for solar-powered lights:

1. High Capacity: Compared to other commonly used lithium-ion cell sizes like 18650, 32650, and 32700 batteries offer higher capacity. This means they can store more energy, allowing solar-powered lights to provide illumination for an extended period after sunset. These high-capacity batteries are particularly suitable for applications that require longer operating times.

2. High Discharge Rate: 32650 and 32700 batteries typically have higher discharge rates, meaning they can deliver higher current output. This is crucial for solar-powered lights as they need to produce sufficient brightness during nighttime or low light conditions. Batteries with high discharge rates ensure that the lights can operate properly.

3. Long Lifespan: 32650 and 32700 batteries are engineered and optimized to provide longer service life and cycle counts. They are designed to withstand years of charge-discharge cycles while maintaining high performance. For applications like solar-powered lights, these batteries can endure prolonged use and maintain their performance over time.

4. Enhanced Safety: Due to their larger size, 32650 and 32700 batteries generally offer better heat dissipation, which contributes to improved safety. This helps mitigate the risk of battery overheating, making them safer for outdoor environments where solar-powered lights are often used.

It's important to note that the selection of battery sizes for solar-powered lights also depends on specific design requirements and application scenarios. Other factors such as cost, charging requirements, and available space also need to be considered.

In summary, the high capacity, high discharge rate, long lifespan, and improved safety make 32650 and 32700 batteries common choices for solar-powered lights.