How Does Wi-Fi Use Affect Computer Battery Life?

Question: How Does Wi-Fi Use Affect Computer Battery Life?

The Wi-Fi network protocol requires power (electricity) to operate the radios used to send and receive data. How exactly does your usage of Wi-Fi affect a computer's power consumption, specifically the life of battery-operated devices?

Answer: The power required by a Wi-Fi radio is measured in decibel millwatts (dBm). Wi-Fi radios with higher dBM ratings tend to have greater reach (signal range) but will generally utilize more power than those with lower dBM ratings.

Wi-Fi consumes power whenever the radio is on. With older Wi-Fi network adapters, the amount of power used is generally independent of the volume of network traffic sent or received, as these systems keep the Wi-Fi radio powered at all times even during times of network activity.

Newer Wi-Fi systems that implement the WMM Power Save power saving intelligence may according to the Wi-Fi Alliance save between 15% and 40% over other Wi-Fi systems.

On Linux, the LessWatts.org initiative has also created its own Wi-Fi Power Save Poll protocol that intelligently powers off the network adapter for short periods of time to save energy.

A relatively new technology, using solar energy to power Wi-Fi routers is also an area of active research and product development.

Overall, the battery life (the length of uninterrupted operating time possible with one full battery charge) of Wi-Fi devices varies depending on several factors including:

• the type of battery installed
• the dBm rating of the Wi-Fi radio (network adapter)
• how often the Wi-Fi radio is turned off versus on
• Wi-Fi power savings modes available on the device
• the power needs of the display (screen), processor and other elements of the hardware separate from Wi-Fi

To determine the exact power consumption of your Wi-Fi device, you should empirically measure it under real world usage models. You should notice a significant difference in battery life depending on whether you use Wi-Fi.