Until they make a mini-nuke battery, it won't even be remotely possible to run a good enough light off a battery. If you did actually attempt this, you'd have to have like 100 car batteries to last any appreciable amount of time. In other words, nope not possible with current technology.
I assume this is because where you are growing doesn't have an outlet. If there are other outlets near where you are, it's easy to install one where you want to grow. I just did this and it took $5, 20 minutes on google, and 2 hours putting it in. Just google "installing an outlet using an existing outlet." And make sure you turn off the breaker and check to make you turned off the right breaker.
Yeah but I need to do this without the other people in my housr seeing it Edit:would it be possible to do that without being noticable?
Putting in the outlet would be possible without people knowing as long as no one is home when you shut off the power. But it's much easier in some situations than others. I'm growing in a closet in my attic and there is an outlet right on the other side of the closet wall. And there is no drywall in the attic so there was no cutting involved. If you have to deal with cutting up walls, someone will notice unless you have some serious skills. When you add an outlet to a circuit, there will be a wire running out the back of the original outlet to the new outlet. So if you can access the back side of the wall with the outlet, you are all set. As for installing it, here is a good link Adding a New Outlet from an Existing Outlet - Self Help and More . Anyone can do it but you have to use caution when working with electricity. You can get those electricity detectors people use for christmas lights for cheap. Never touch a bare wire unless you are 100% certain there is no electricity going through it.