Connected Battery Jumper Cables Wrong

[funwithahoe]

This happened to me with my F-150. We were on our way home from vacation about 1:30 in the morning. Some guy needed a jump. I said red on the positive. He responded yes. Well he didn't know red or positive. My battery was smoking. Now I always make the connections myself. The clamp that connected to the battery post was broken somehow. Luckily I was able to make enough of a connection to make it the remaining hour home. This was a couple of years ago. My 150 is fine. I did eventually have to replace the battery. But it was 12 years old so it was about time to replace it.

Thanks for all the posts - I think I am lucky that no batteries blew up - Can't imagine that wold have made my mug look any better!

 

[rjkobbeman]

Having a significantly weaker battery in the chain probably saved you. If you connected together two healthy batteries (or course, why would you?), you probably would have had a different outcome.

Another factor could be your jumper cables. They may have been a weak link. You can buy big beefy cables, but they don't seem to be the norm.

 

[funwithahoe]

Having a significantly weaker battery in the chain probably saved you. If you connected together two healthy batteries (or course, why would you?), you probably would have had a different outcome.

Another factor could be your jumper cables. They may have been a weak link. You can buy big beefy cables, but they don't seem to be the norm.

You are right!!

 

[dcyrilc]

Having a significantly weaker battery in the chain probably saved you. If you connected together two healthy batteries (or course, why would you?), you probably would have had a different outcome.

Another factor could be your jumper cables. They may have been a weak link. You can buy big beefy cables, but they don't seem to be the norm.

You are right!!

...and they're expensive.

 

[DiezNutz]

Fun,

I think you're OK. If you did any serious damage, you would already know about it - when it comes to electronics or fuses/fusible links, they're done as soon as you let the smoke out of them. It did put a strain on your truck alternator, but obviously not enough to kill the rectifiers and probably no worse than the load from starting the engine.

The other major factor that saved you here, is you just don't really ever get a good low-impedance/high-current connection with jumper cable clamps. Despite the size of the clamp, there really is not much actual contact area (and therefore current-carrying capacity) with the battery terminal or clamp. Both of which are typically somewhat oxidized anyway, which makes the resistance of the connections even that much higher.

Which is why:
1) You can't usually just start the car having the dead battery right away, you usually have to try to "charge" it some from the booster vehicle first. Because you can't pull all of the amps needed to crank the dead car through the jumper cables and weak clamp connections.
2) Jumper cable clamps heat up with use.
3) Jumper cables with really heavy gauge wires are useless anyway because you can't improve much on the clamp connections, which are the bottleneck.

If you could have gotten solid low-impedance connections between the two systems, then odds are you would have blown something up - perhaps literally.

And since I see at least one flawed set of jumper connections posted, it wouldn't hurt to review the proper technique:

1) + clamps to + terminals of both batteries (keep - clamps from touching anything)
2) - clamp to - terminal of good battery.
3) - clamp to solid bare metal of engine or transmission of car with dead battery (e.g., engine block, motor mount bracket). This last connection is when the spark happens, and you don't want that near the dead battery, which could ignite hydrogen gas venting from the dead battery, causing it to explode in your face. Like this one:

Remove connections in the exact reverse order. :thumbsup:

 

[funwithahoe]

Fun,

I think you're OK. If you did any serious damage, you would already know about it - when it comes to electronics or fuses/fusible links, they're done as soon as you let the smoke out of them. It did put a strain on your truck alternator, but obviously not enough to kill the rectifiers and probably no worse than the load from starting the engine.

The other major factor that saved you here, is you just don't really ever get a good low-impedance/high-current connection with jumper cable clamps. Despite the size of the clamp, there really is not much actual contact area (and therefore current-carrying capacity) with the battery terminal or clamp. Both of which are typically somewhat oxidized anyway, which makes the resistance of the connections even that much higher.

Which is why:
1) You can't usually just start the car having the dead battery right away, you usually have to try to "charge" it some from the booster vehicle first. Because you can't pull all of the amps needed to crank the dead car through the jumper cables and weak clamp connections.
2) Jumper cable clamps heat up with use.
3) Jumper cables with really heavy gauge wires are useless anyway because you can't improve much on the clamp connections, which are the bottleneck.

If you could have gotten solid low-impedance connections between the two systems, then odds are you would have blown something up - perhaps literally.

And since I see at least one flawed set of jumper connections posted, it wouldn't hurt to review the proper technique:

1) + clamps to + terminals of both batteries (keep - clamps from touching anything)
2) - clamp to - terminal of good battery.
3) - clamp to solid bare metal of engine or transmission of car with dead battery (e.g., engine block, motor mount bracket). This last connection is when the spark happens, and you don't want that near the dead battery, which could ignite hydrogen gas venting from the dead battery, causing it to explode in your face. Like this one:

Remove connections in the exact reverse order. :thumbsup:

Thanks Diez. - Good info - Truck and Impala have made it abou 1000 miles each or so with no symptoms so I agree - Not enough load carrying cappacity to do the damage that would be possible.

Was that battery photo taken by you and if so did the explosion spray acid??

 

[DiezNutz]

Nope, that was just a photo I found on the interweb. Thankfully I've only ever witnessed one battery explosion (intentionally, from a safe distance), which was pretty spectacular. By all accounts I know of, they always spray acid and shrapnel. Supposedly a few thousand people each year suffer serious eye injuries or blindness from exploding lead-acid batteries. Wearing safety goggles when working around them is a VERY good idea.

Some eyewitness accounts for your enjoyment: Battery Safety

 

[sharafm2002]

Thanks Diez. - Good info - Truck and Impala have made it abou 1000 miles each or so with no symptoms so I agree - Not enough load carrying cappacity to do the damage that would be possible.

Was that battery photo taken by you and if so did the explosion spray acid??

I did something fu**** stupid.
my tractor was having issues starting in a cold weather. so i went to jump it with my other tractor. so just being so freaking cold and dump, i connected the cables to the right terminals on the running tractor. then i just assumed (which was my fU*** up) that the bigger terminal was the positive. so i connected the positive terminal to it and it sparked and melt part of the battery cable so i took it right off. it took only a split of second before i took the cable off.
i reconnected the jumping cables the right way and fired up the tractor and no problem. several days later. i started having issues starting the tractor. (when i go to start the tractor it either gives me a nice start with no problems or it just gives a soft one click as if the battery dead. then i started noticing sparks going on around the starter and now i can't get it to start.

any thoughts ???

 

[George2615]

Sounds like there may be some that need these foolproof jumper cables.

Michelin Smart Cables jumper cables - About.com Cars product review - Michelin Smart Cables jumper cables

 

[sharafm2002]

well i just learned the hardway to always check terminals before connecting cables. but thanks for the suggestion. although it doesn't help with my current situation right now