The answer to this lies in the purpose that you would be using the trail camera for. If your camera is placed at a location where you can access it frequently with ease, lithium batteries are a good option. If your camera requires a greater power source, you could also go opt for an external battery box. However, they are comparatively more expensive. In case you are looking for a more permanent solution to manage the power source for your trail camera, solar panels would be a wise choice and would save you from additional expenditures of replacing the battery.