"Battery" is a song by the American heavy metal band Metallica, and serves as the opening track to the band's third studio album, Master of Puppets.

The song is composed in the key of E minor.^[2] It has a similar structure to the opening track of Ride the Lightning ("Fight Fire with Fire") and ...And Justice for All ("Blackened").^[3] The song begins with an acoustic guitar introduction before drums and bass guitar come in with distorted guitars playing a more melodic sequence. Then the song cuts into a very fast thrash metal riff which is the base for the rest of the song.

James Hetfield improvised the main riff to the song while relaxing in London.^[4]

The lyrics discuss control of anger over one's behavior. However, the theme of the song is based around the San Francisco thrash scene in the 1980s. The most prominent club played by Metallica was the Old Waldorf at 444 Battery Street in downtown San Francisco.^[5] The lyric "Cannot kill the family, Battery is found in me" is a statement that society does not understand the scene and that those within it ("the family") will defend it as a show of solidarity against the glam metal scene that was popular in the Los Angeles area.^[6] The tone of the song is of familial ties and the positive release of energy through interest in metal.

AllMusic's Steve Huey called the songs "Battery" and "Damage, Inc." "two slices of thrash mayhem".^[7]

A readers' poll in Rolling Stone placed "Battery" at number 9 on its 10 Best Metallica Songs list.^[8]

Kerrang! ranked the song number 5 on its 20 Greatest Metallica Songs Ranked list, commenting, "Echoing Ride The Lightning's superb Fight Fire With Fire in its medieval-tinged acoustic opening before bombing headlong into a masterclass in lean, taut thrash metal, Battery was the fine-tuned statement of intent from a band ready to make their serrated sound a platinum success."^[9]

Revolver magazine hosted a fan poll and "Battery" was ranked number 4 out of "Top 5 Metallica Songs".^[10]

Loudwire ranked "Battery" at number 7 in its "Best Metallica Songs" list.^[11]

Billboard ranked the song at number 4 on its "Top Ten Greatest Metallica Songs" list.^[12]

The song was first played live on March 27, 1986, along with the songs "Welcome Home (Sanitarium)" and "Damage, Inc".^[13]

"Battery" used to be a constant part of the band's live set list, frequently as either the opening or closing song. In some cases, it was used as a song before the intermission in concerts. Since 2008, the song has been dropped from most set lists. When played live, the song may stop before the interlude and James Hetfield asks the crowd, "Are you alive?... How does it feel to be alive?" (This can be heard on the live album S&M.)^[6]

"Battery" has been played live 989 times up to September 2022.^[14]

• This song (along with the entire Master of Puppets album) was covered by Dream Theater as part of its world tour in 2002 and has been released as an official bootleg recording.^[15]
• This song was covered by the band Machine Head for Kerrang!'s Master of Puppets: Remastered, and is also included as a bonus track on some versions of the band's album The Blackening.^[16]
• It was also covered by the a cappella metal band Van Canto on its first album, A Storm to Come.^[17]
• On "Animetal Rebirth Heroes", Animetal uses the riff for "Battery" throughout the entire song "Touch" with some changes in between.
• This song was covered by the band Ensiferum for Evil Ultimate Metal Covers No. 55. It was also on the single "Tale of Revenge".
• Beatallica, a mash-up band that combines Metallica and The Beatles, combined "Battery" with "The Ballad of John and Yoko" to create "The Battery Of Jaymz And Yoko" on the Masterful Mystery Tour album.
• Die Krupps covered the song for A Tribute to the Four Horsemen.
• The song was covered by Eric AK (Flotsam & Jetsam), Dave Lombardo, Mike Clark and Robert Trujillo for Metallic Assault: A Tribute to Metallica. Lombardo played the song with Metallica on stage when Lars Ulrich missed the 2004 Download Festival, and Trujillo became a member of Metallica in 2003.
• It was covered by Prototype for Phantom Lords - A Tribute to Metallica released by Dwell Records in 2002.
• Harp tribute duo Harptallica covered the song's introduction on the album Harptallica: A Tribute.
• The pop-punk band Lagwagon borrows the line "smashing through the boundaries/lunacy has found me" for the song "Raise A Family" found on their 2000 release Let's Talk About Leftovers'.
• Deftones covered the song on the second night of the band's "One Love For Chi" concerts in 2009 with accompaniment from Dave Lombardo of Slayer on drums, Alexi Laiho of Children of Bodom on guitar, Robert Trujillo of Metallica on bass guitar, Daron Malakian and Shavo Odadjian of System of a Down on guitar and bass guitar respectively, and Greg Puciato of The Dillinger Escape Plan on vocals.^{[citation needed]}
• Sum 41 covered this song on their tour but they normally played the introduction of this song.

• The song appears as one of playable tracks in Rock Band 2, Guitar Hero: Metallica and Fortnite Festival.
• The song appears in the 2011 indie film Hesher.^[18]
• The song appears in the 2012 film Project X.
• The song appears in the 2013 film Metallica: Through The Never.

On August 13, 2018, a man named Chris Watts murdered his family.^[19] A report on the situation included how Watts Googled lyrics to Metallica's "Battery"^[20] after he had disposed of the bodies of his pregnant wife and children.^[21] It stirred up controversy in the media, some reports trying to link the song to the murder.^[22][23]

Credits are adapted from the Master of Puppets's liner notes.^[24]