Crossed poles on jumper cables

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Yep, my fault, lets get that out of the way.

Ok, my neighbor, who has a decrepit vehicle and plenty more problems than that, texted my wife asking for a jump, so off I went.

Upon arrival, I noticed the lights on her car were on pretty bright, and she was trying to start her car. It was trying mightily, sounded like it was just barely not starting.

She informed me her battery was only three months old, and the car had been parked since Thursday. Her driveway was such that I had to pull in behind her and clamp two sets of cables together. When attaching to her car, i noticed a spark upon connecting to what thought was her positive terminal. Yes, I crossed polarity. There was only a spark, I never even fully clamped the clip to the negative terminal. However, the negative cable was clamped to positive on her end. My car, the donor car, was not running, and obviously her ignition was off too. I corrected for polarity and then started my car. Her car tried to start, and wouldn't. Behaved just as it was when I got there- barely not starting. I tried swapping my battery in- same thing. Tried bypassing solenoid- no dice. Gave the starter a few good whacks with the wrench for what that's worth. Everything remained the same, and for me that's the end of what I know to try.

My car runs like normal. Did I break anything, or is it more likely her car has the same issue it always did, whatever that is? I couldn't sleep knowing I did in some poor family's only vehicle.

EDIT: And now, really bizarrely, 15 minutes after I posted this and several hours after doing the deed, her car started and is running as normal.
 
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There is no telling, you might have fried some of her electronics. When I was a young teenager, I did this to an expensive tractor battery and melted the terminal. Fortunately, that tractor was mostly mechanical in nature.
 
Don't worry about it....her car started and is running after not being running even after you made that mistake...move on and forget about it.

Oh and remember...No good deed goes unpunished.
 
1. Buy a jump box with reverse-polarity protection. I replaced the cables in both of our vehicles with li-ion jump-starters.

2. If it was cranking, then why did you try jumping her car?

3. If it was cranking, then why did you whack the starter? All she can thank you for there is possibly damaging her starter...

//

I stopped to help an old lady in a parking lot nearby a while back. Her son worked at the Starbucks in that same complex, so, even though it was cold, she had a place to hang out while they waited for a tow truck (which hadn't been called by the time I arrived). Why? Even though she told me her son told her she needed a jump, her car was cranking full-speed. Unfortunately, I did not have anything to read the codes for her CEL. I convinced her to have her car towed somewhere to diagnose the issue and that a jump would do nothing for her.
 
Only mistake you made was whacking the car. I know that is a way yo get a stuck starter going but anything that breaks on the car will cast a wary eye towards that repair technique.

As a kid I've taken jumper cable and make a 30 second spark show before I know that batteries sometimes blow up. I've done it many times to impress the buddies. "Look this battery is Hawt" BZZZZZZ!!!!!! BZ BZ BZZZZ!!!!!!

never a problem. highly unlikely you caused any issue.
 
All I can add is ALWAYS WEAR SOME EYE PROTECTION AROUND BATTERIES. Only seen it once in 50 years but it is real. I would always charge my boat battery the night before and in the morning I would hit the trim button (Mercruiser) and could tell by the sound if the battery sounded good. (to me) This one time I did that and the battery blew the .... UP! I think the water level maybe got low and there was a lot of hydrogen in there?? I took it to Wallyworld as a trade in, and asked her to show it to their workers as a reminder. What saved me was I was up by the console where the trim switch was instead of hovering over the battery.
 
Many, many, many people think that jumper cables are the end-all solution to a car that won't start. Doesn't matter that it can be cranking 100% normal, just doesn't fire up or the headlights are burning full bright, not dimming, and so on.

As for this situation, just move on and don't give this a 2nd thought. Your car is fine.
 
Originally Posted by hallstevenson
Many, many, many people think that jumper cables are the end-all solution to a car that won't start.

LOL...it's a bit of a running joke for me as I sarcastically point out pretty often while on the road. You see a disabled vehicle on the shoulder of the road...it could have 4 flat tires, a connecting rod through the engine block, and transmission literally falling out from underneath. There will almost always be a car in front of it with jumper cables hooked to it.
 
Originally Posted by 3Aone
Yep, my fault, lets get that out of the way.

Ok, my neighbor, who has a decrepit vehicle and plenty more problems than that, texted my wife asking for a jump, so off I went.

Upon arrival, I noticed the lights on her car were on pretty bright, and she was trying to start her car. It was trying mightily, sounded like it was just barely not starting.

She informed me her battery was only three months old, and the car had been parked since Thursday. Her driveway was such that I had to pull in behind her and clamp two sets of cables together. When attaching to her car, i noticed a spark upon connecting to what thought was her positive terminal. Yes, I crossed polarity. There was only a spark, I never even fully clamped the clip to the negative terminal. However, the negative cable was clamped to positive on her end. My car, the donor car, was not running, and obviously her ignition was off too. I corrected for polarity and then started my car. Her car tried to start, and wouldn't. Behaved just as it was when I got there- barely not starting. I tried swapping my battery in- same thing. Tried bypassing solenoid- no dice. Gave the starter a few good whacks with the wrench for what that's worth. Everything remained the same, and for me that's the end of what I know to try.

My car runs like normal. Did I break anything, or is it more likely her car has the same issue it always did, whatever that is? I couldn't sleep knowing I did in some poor family's only vehicle.

EDIT: And now, really bizarrely, 15 minutes after I posted this and several hours after doing the deed, her car started and is running as normal.


Intermittent problems are the worst. this vehicle you tried to help will either keep having problems or fail completely which will enable a successful diagnosis. Lesson here is don`t exceed your knowledge level although it is tempting.
 
You did a good deed and I don't think any wrong came from crossing poles as "quickly" as you did.
Remember, it was only a quick touch. Sure, something bad could have happened but it didn't.
Apparently, touching + w/ - or visa-versa wasn't severe enough in you case.

Sleep well,

CB
 
You tried to do a good deed and based on your description I'm doubtful you did any damage to neighbor's vehicle. Stuff happens, lesson learned, move on.

On a related note, I recently wrote about a good sam jumper cable experience here. There the dude cracked the live cable ends from the good battery vehicle together multiple times to check for spark.
crazy.gif
Afaik donor vehicle ok, but not for lack of trying. In that case, example of no good deed going unpunished.
 
There was enough resistance on something-- rusty cables-- that you didn't break anything. If you had a clean connection you'd have seen the full 24 volt arc welding experience. Just think of how many times one connects cables, they don't work, then they go around wiggling the alligator clips, sparks flying, until the donee car reports a bright dome light and tries with success.
 
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