A guy replaced my car battery and connected black wire followed by red cable. Google says it should be otherwise. When he connected the black one my alarm beeped once. No sparks, fire, flickering lights or anything out of ordinary. I drove the car for a few hours after that, everything as usual.

Despite that should I be worried that the battery may be short-circuited or damaged? Right now it's parked outside at -6 C, don't know if that's much relevant.

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    Welcome to Motor Vehicle Maintenance & Repair! Commented Jan 10 at 21:02
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    Harm to the battery is unlikely, but don't let "a guy" near it again. A battery short-circuit can literally weld a wrench across the terminals and burn out the car. My kids tried to charge a small (motorcycle) battery powering a CB radio. The battery clips touched, and they called me to deal with it. Having no tools or rags to hand, I chose to take off the clips by hand: forty years on, I still have a + -shaped scar on my thumb from the positive terminal. Commented Jan 11 at 14:41
  • Next time I'll just replace it myself. Sorry to hear about the scar, that's definitely a story to tell!
    – Fleeck
    Commented Jan 12 at 7:56

1 Answer 1


In this case, it should be considered a no harm, no foul situation ... however, you are right to worry about it a little. The reason you should put the positive side on first and then the negative is that with the negative first, there's a chance you can ground the positive side out and cause bigger issues. For instance, if you already had the negative side affixed, then while trying to bolt down the positive side your wrench inadvertently touches something and grounds, you have sparks and problems. This situation is completely avoided by putting the positive side on first. That you saw no sparks and the vehicle seems to be running as expected, I'd suggest all is fine.

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    Thanks! Do you think it's worth to double-check with a battery tester?
    – Fleeck
    Commented Jan 10 at 21:09
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    @Fleeck I think the main mission of this site is to convey the feeling that, if you have a tester and a concern, you should always feel free to test your vehicle. I agree with Paul, though, that you almost certainly won't find any issues. If you do, come on back and we'll be happy to help more!
    – Bob Cross
    Commented Jan 10 at 21:50
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    @Fleeck: Paraphrasing what Pᴀᴜʟsᴛᴇʀ2 already said: the battery doesn't care (or even know) what order the terminals are attached; the reasons for attaching them in a specific order are to help avoid dangerous situations while installing the battery in the car. If those dangers didn't happen, the battery doesn't know any different, and you're fine :)
    – psmears
    Commented Jan 11 at 14:48
  • @psmears - Well said and thanks for the add. Commented Jan 11 at 14:54
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    "Do you think it's worth to double-check with a battery tester?" - No. The guy didn't follow the best protocol for safety, but that protocol is to avoid accidents. No accidents happened, so there's absolutely no reason to suspect a problem with your battery.
    – marcelm
    Commented Jan 11 at 22:36

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