Yes, you can use 4 or 8 rechargeable AA batteries as backup. 

No, Only one charger, but can charge two batteries at the same time. 

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 

You can view photos and videos from this WiFi trail camera without removing it from the mount. And you can set the camera in the APP. This is very useful for cameras mounted in high places or hard-to-reach places. 

Hello, this trail camera can provide 4K video and 30MP photo. It's clear enough to see what you're shooting with this hunting camera. So you get clear images even in the dark. More importantly, this hunting camera has WiFi connection and APP control. That means you can use the APP to preview and download photos on your phone. It's so convenient.