# New car battery - which post do I connect first?

**URL:** <https://boards.straightdope.com/t/new-car-battery-which-post-do-i-connect-first/640315>\
**Category:** Factual Questions\
**Created:** [November 8, 2012, 2:23am UTC](https://boards.straightdope.com/t/new-car-battery-which-post-do-i-connect-first/640315 "2012-11-08T02:23:14Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![Northern\_Piper](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/northern_piper/32/5304_2.png) [@Northern\_Piper](https://boards.straightdope.com/u/Northern_Piper)\
**Post date:** [November 8, 2012, 2:23am UTC](https://boards.straightdope.com/t/new-car-battery-which-post-do-i-connect-first/640315/1 "2012-11-08T02:23:14Z")

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Putting in a new battery - does it matter which post I attach first?

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**Author:** ![Crafter\_Man](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crafter_man/32/458_2.png) [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)\
**Post date:** [November 8, 2012, 2:29am UTC](https://boards.straightdope.com/t/new-car-battery-which-post-do-i-connect-first/640315/2 "2012-11-08T02:29:41Z")

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Doesn’t matter, but generally safer to do positive first in case your wrench makes contact with ground.

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**Author:** ![Joey\_P](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@Joey\_P](https://boards.straightdope.com/u/Joey_P)\
**Post date:** [November 8, 2012, 2:33am UTC](https://boards.straightdope.com/t/new-car-battery-which-post-do-i-connect-first/640315/3 "2012-11-08T02:33:42Z")

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Disconnect the negative first.  
Connect the positive first.

That’s the way you always do it.

While it technically doesn’t matter, you do it this why because you’ll have a short to ground if you connect the negative first and then you go yo put the positive on and your wrench touches something metal while it’s on the positive post. Been there, done that. I don’t forget which order anymore. If the negative is disconnected and you do this, nothing happens, there’s no circuit to short.

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**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\
**Post date:** [November 8, 2012, 2:48am UTC](https://boards.straightdope.com/t/new-car-battery-which-post-do-i-connect-first/640315/4 "2012-11-08T02:48:06Z")

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i agree that

if the car is a negative ground (USA) then connect the positive first.

the non-grounded terminal is the first to connect.

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**Author:** ![Northern\_Piper](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/northern_piper/32/5304_2.png) [@Northern\_Piper](https://boards.straightdope.com/u/Northern_Piper)\
**Post date:** [November 8, 2012, 3:09am UTC](https://boards.straightdope.com/t/new-car-battery-which-post-do-i-connect-first/640315/5 "2012-11-08T03:09:01Z")

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Thanks guys - knew there was a particular order but couldn’t remember it.

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**Author:** ![Northern\_Piper](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/northern_piper/32/5304_2.png) [@Northern\_Piper](https://boards.straightdope.com/u/Northern_Piper)\
**Post date:** [November 8, 2012, 3:28am UTC](https://boards.straightdope.com/t/new-car-battery-which-post-do-i-connect-first/640315/6 "2012-11-08T03:28:57Z")

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Put in the new battery, positive first, then negative - no sparks or acid explosions- turned the key and a surge of power! Thanks, all.