When selecting batteries for unmanned ships, the following factors need to be considered:

1. Battery type: Unmanned ship batteries generally use lithium batteries. Lithium batteries are lightweight and fast to charge, but they are relatively expensive.

2. Battery capacity: The larger the capacity, the more electricity the battery can store and the longer the navigation time. But the larger the capacity, the more bulky and expensive the battery will become. Therefore, it is necessary to choose the battery capacity reasonably based on the needs and budget of unmanned ships.

3. Charging time: Charging time is also an important factor because the battery needs to be charged frequently during use. Choosing a fast charging battery can reduce unnecessary waiting time.

4. Battery life: The lifespan and quality of a battery are directly related. A good battery has a long lifespan and a longer lifespan, but the price is relatively high.

5. Safety performance: The safety of battery use is a crucial issue. It is necessary to choose batteries with protective devices to prevent short circuits and overcharging, in order to avoid safety accidents caused by battery fires or explosions.

6. Battery weight: The balance and flexibility of the ship are quite important. Therefore, it is necessary to search for batteries with moderate weight in order to maintain balance without significantly affecting the performance and sailing time of the vessel.

7. Battery size: Battery size is also an important factor because unmanned ships usually have very small space, and batteries should be as small as possible to accommodate the volume size of unmanned ships.

8. Manufacturer credibility: Choosing well-known brands of batteries and manufacturers can ensure the quality and performance of the batteries. At the same time, these manufacturers also provide comprehensive technical support and after-sales service.