I have a Canon Eos 1100d camera. I am wondering if there is a method to use this camera without a battery, and connect to continuous power? I want to keep this camera open for a lot of days without charging the battery. It is possible?
Canon makes AC adapters for pretty much all of their cameras, but they can be a bit expensive. In your particular case, the Canon ACK E10 is the AC adapter for your camera. This will provide continuous power to your camera, but it is also $65. Third party options can be cheaper, but make sure you get a reputable one if you do so as to avoid damaging the camera.
It typically runs up in to the battery compartment through a little cover that can allow the cable to pass through and takes the place of the battery.
I've also found a solution around $5 to produce this permanent power supply (kind a battery simulator) using the 7808 voltage regulator build into a battery package.
Here is the YouTube Video