An electric drill that is not AC powered but dependent on a battery source is called a cordless drill. These devices are available as an alternative to AC powered drills and until recently could not match up to the performance and power of electric drills.

Todays cordless units are better adapted to the requirements of a construction worker as they operate on a hammer mechanism along with a clutch system to allow driving screws without damaging them.

Some cordless drills even come as right angled drills allowing operation in tighter spots. Some cordless variants are quite capable of drilling holes over an inch in diameter, although doing that does use a lot of batter power.

You can gain a better understanding about these devices by reading cordless drill reviews and ratings online.

The only problem with cordless drills is that the battery will run out at some point of time requiring a replacement. That is why users often keep another spare on charge replacing the depleted battery as soon as possible to continue work uninterrupted.