# How much energy a day does a cell phone use?

It seems like every 6 months they are coming out with a new high tech phone, and each time the battery life is improving. So obviously it can be hard to determine the amount of energy your phone uses, and it obviously depends on if you use it fairly often or not.

A few tips to reduce energy use include:

• unplugging your charger when not being used.
• Decrease your phones black light settings
• Turn it off completely when you go to a movie or travel via airlines- you’ll still get your texts when you turn it back on.
• Only buy a new phone when you need it.
• Only charge your phone when you need too.

First off, the amount of energy used by your cell phone is going to depend on a) which model phone it is, and b) what exactly you’re doing on your phone.  For argument’s sake, let’s assume that you have a non-energy-efficient phone, and that you run the battery down all the way every day.

According to a study by the Lawrence Berkeley National Laboratories, an average cell phone CHARGER uses:

3.68 watts while charging

2.24 watts while plugged to your phone but not charging (battery full)

0.26 watts when plugged into the wall but not your phone

If you plug your phone in before you go to bed, it will typically take about three hours to fully charge.  The remaining five hours (while you’re asleep) it will continue to drain energy.  So 3×3.68=11.04, and 5×2.24=11.2.  Total of 22.24 watts per day, IF you’re a tree hugger and unplug your charger like you should.  If you happen to leave your charger constantly plugged in, your daily use will be an additional 4.16 watts.