Yes, it's detachable. 

Hello, thank you for your question, do not need a solar controller, cut the DC line in the middle, come up with positive and negative junction, plug in the 12V lithium battery will be fine, we generally do not recommend that you do so, worried that you will damage the solar panel, Thanks &Best regards 

No, there is no built-in battery in this solar panel. But it supports all the power banks charging, so that you can store power for using. 

Yes, the hunting camera comes with a solar panel with a 3m cable, the solar panel can be adjusted to suit the location and How do you get the electricity? How much capacity does the hunting camera have The product itself has a battery capacity of 7800mAh and is powered by the solar panel. Please fully charge it with the adaptor before use. You do not need to remove it often to charge it in summer and in sunny places 

Yes, but you need to contact us to purchase the bracket and extension cable separately, the extension cable is 2M