Got jumper cables backward. Sparked and sizzled. Should I try again?
January 1, 2019 10:49 PM Subscribe
Trying to jumpstart my dead car. Thanks to a mislabeled battery on the donor car, I hooked up the jumper cables backwards at first -- a couple of brief contacts (sparks), then one for ~30 seconds, stopping when I noticed a low sizzling sound. The donor car was not cranked, and starts up fine after everything was disconnected (and the mistake discovered). Is it safe to try again, or have I done (or will I do) dangerous damage to either car?
I just got back from vacation to find my '96 4Runner had a dead battery. Got another SUV in to jump it off. Red clamp to the dead battery's +, other red to good +, black to good -... but when I went to ground the other black clamp, there was a bit of sparking. Tried another spot, thinking I was poorly grounded or just too close to the battery or something -- same thing. Did some panic searching that suggested this wasn't unusual (??), so tried one more time (the sparking stopped after contact), but disconnected it again after I heard what sounded like a low sizzling sound from the bad battery. Less than 30 seconds of contact altogether, and the good car was never cranked. (Also, the good car started up fine after everything was disconnected).
Looking closer at the good battery, I realized that whoever installed it mislabeled the damn thing -- the red tape was on the negative terminal, and the black tape on the positive. Now I'm worried about whether it's safe to try again with the right configuration -- I've heard a lot of horror stories about shorts, fires, hydrogen gas leaks, exploding batteries, etc. when people talk about the importance of hooking up jumper cables in the right order. Should I try again, or is there a good chance I have done (or will do) some dangerous damage to either car? Difficulty level: one car needs to go to the airport tomorrow morning, and the other one needs to go to work.
I just got back from vacation to find my '96 4Runner had a dead battery. Got another SUV in to jump it off. Red clamp to the dead battery's +, other red to good +, black to good -... but when I went to ground the other black clamp, there was a bit of sparking. Tried another spot, thinking I was poorly grounded or just too close to the battery or something -- same thing. Did some panic searching that suggested this wasn't unusual (??), so tried one more time (the sparking stopped after contact), but disconnected it again after I heard what sounded like a low sizzling sound from the bad battery. Less than 30 seconds of contact altogether, and the good car was never cranked. (Also, the good car started up fine after everything was disconnected).
Looking closer at the good battery, I realized that whoever installed it mislabeled the damn thing -- the red tape was on the negative terminal, and the black tape on the positive. Now I'm worried about whether it's safe to try again with the right configuration -- I've heard a lot of horror stories about shorts, fires, hydrogen gas leaks, exploding batteries, etc. when people talk about the importance of hooking up jumper cables in the right order. Should I try again, or is there a good chance I have done (or will do) some dangerous damage to either car? Difficulty level: one car needs to go to the airport tomorrow morning, and the other one needs to go to work.
In light of zenon's answer of needing to go to the auto parts store, and it sounds like you are up against a time deadline, do you have Triple A? I've had them come out to my home and replace batteries a couple of times. They'll test the battery first to let you know if it can be charged or needs to be replaced. I don't know if the drivers would carry fuses but you could ask when you call in.
posted by vignettist at 12:43 AM on January 2, 2019
posted by vignettist at 12:43 AM on January 2, 2019
You may have done more damage than just to the battery. Wiring can fry from jumping with the cables reversed, and that's going to take an auto electrical specialist to fix. The sizzling sound may have been wires frying. That said, you can try the jump with the cables connected properly, but watch for arcing or smoke, and disconnect immediately if you see any.
posted by Kirth Gerson at 3:13 AM on January 2, 2019
posted by Kirth Gerson at 3:13 AM on January 2, 2019
The charged battery will have a higher voltage than the uncharged one so you may have slightly reversed the polarity in the dead car (to the tune of a volt or two). The car with the decent battery would have seen this as a near short, so only the battery would have suffered. The dead car's electronics (ECU, dashboard, etc) could have suffered from this, but the voltage may well not have been big enough to make a difference.
The jump leads might bear examination - did they get warm? They're designed to pass a lot of current, but it's worth checking.
Sizzling: you were drawing a chunk of current from both batteries, even the dead one, so they would offgas hydrogen and/or boil the battery acid. These will both sizzle.
I doubt you've damaged the car's wiring loom because the connection was battery to battery directly and the wiring loom was not involved - though checking the fuses is a good idea, they should die before the wiring got damaged.
I would use a charger at this point rather than jump anything; but at least run the good car for a while to top its battery up from the alternator before trying again. I would also check the electrolyte level in the batteries and top up with distilled water if they are low. Crossing wires might do that because of the overheating, and it may have been your initial problem anyway.
Our school physics lab had a 'cutaway model' of a lead acid battery, which was the result of the teacher's son doing exactly this with a pair of tractors. That was during, though, not after.
posted by How much is that froggie in the window at 4:05 AM on January 2, 2019 [2 favorites]
The jump leads might bear examination - did they get warm? They're designed to pass a lot of current, but it's worth checking.
Sizzling: you were drawing a chunk of current from both batteries, even the dead one, so they would offgas hydrogen and/or boil the battery acid. These will both sizzle.
I doubt you've damaged the car's wiring loom because the connection was battery to battery directly and the wiring loom was not involved - though checking the fuses is a good idea, they should die before the wiring got damaged.
I would use a charger at this point rather than jump anything; but at least run the good car for a while to top its battery up from the alternator before trying again. I would also check the electrolyte level in the batteries and top up with distilled water if they are low. Crossing wires might do that because of the overheating, and it may have been your initial problem anyway.
Our school physics lab had a 'cutaway model' of a lead acid battery, which was the result of the teacher's son doing exactly this with a pair of tractors. That was during, though, not after.
posted by How much is that froggie in the window at 4:05 AM on January 2, 2019 [2 favorites]
I doubt you've damaged the car's wiring loom because the connection was battery to battery directly and the wiring loom was not involved....
This is not what Rhaomi presented. He or she connected the black cable to a couple of different grounds, but neither was on the dead battery. This would necessarily involve the car's wiring in the circuit. I have seen wiring go up in smoke from doing this, when polarity was crossed.
posted by Kirth Gerson at 7:00 AM on January 2, 2019 [2 favorites]
This is not what Rhaomi presented. He or she connected the black cable to a couple of different grounds, but neither was on the dead battery. This would necessarily involve the car's wiring in the circuit. I have seen wiring go up in smoke from doing this, when polarity was crossed.
posted by Kirth Gerson at 7:00 AM on January 2, 2019 [2 favorites]
Response by poster: Sorry for keeping everyone in suspense -- I'd started writing an update last night but got sidetracked looking at AAA's site. Tl;dr: jumping again did zilch, and there were at least two blown fuses, including the 100A one for the alternator. Had to carpool this morning, and I'll see if AAA can do a battery test and replacement. Hopefully that and new fuses will get it working again, but no clue if there was more electrical damage beyond that. Fingers crossed...
posted by Rhaomi at 11:21 AM on January 2, 2019
posted by Rhaomi at 11:21 AM on January 2, 2019
A AAA truck should be able to handle a battery swap and changing out a few blown fuses, they typically have a pretty good kit in there and technicians who are used to solving problems and making things work. I've been impressed by their ingenuity and effectiveness more than once. If you can buddy up to the tow guy a bit when he (it's probably gonna be a he, though I'd be thrilled to be wrong) shows up, he'll probably go the extra mile for you just to show what he can do. Treat him like he's a hero and he'll try and rise to the occasion. They can do quite a bit to get your car going again.
posted by Anticipation Of A New Lover's Arrival, The at 4:14 PM on January 2, 2019 [1 favorite]
posted by Anticipation Of A New Lover's Arrival, The at 4:14 PM on January 2, 2019 [1 favorite]
Response by poster: Hey all, sorry for not updating -- as you might imagine, this ended up being a bit of a hassle.
So the fuses were pretty much useless, and even that brief surge was enough to damage the battery, alternator, starter, and a lot of the internal wiring. The first guy AAA sent couldn't jump it or diagnose it (due to the fried starter), so I had them tow it to a local Express Oil Change shop (note: always double check where they recommend towing it -- they almost took it to a Hyundai-only place before I caught it).
Anyway, the mechanics there took some measure of pity on me, and charged $0 for labor despite working on it for the better part of two weeks. It wasn't cheap, but they got decent deals on all parts, including a push-button start to avoid having to replace the entire ignition system. Even threw in a free alarm system since the new wiring had to bypass the old one. Grand total was in the high hundreds, though it could have easily been in the thousands (or a total loss). It still drives normally a month and change later.
posted by Rhaomi at 3:13 PM on March 4, 2019
So the fuses were pretty much useless, and even that brief surge was enough to damage the battery, alternator, starter, and a lot of the internal wiring. The first guy AAA sent couldn't jump it or diagnose it (due to the fried starter), so I had them tow it to a local Express Oil Change shop (note: always double check where they recommend towing it -- they almost took it to a Hyundai-only place before I caught it).
Anyway, the mechanics there took some measure of pity on me, and charged $0 for labor despite working on it for the better part of two weeks. It wasn't cheap, but they got decent deals on all parts, including a push-button start to avoid having to replace the entire ignition system. Even threw in a free alarm system since the new wiring had to bypass the old one. Grand total was in the high hundreds, though it could have easily been in the thousands (or a total loss). It still drives normally a month and change later.
posted by Rhaomi at 3:13 PM on March 4, 2019
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Reversing the polarity on the batteries likely killed or significantly shortened the dead batteries life, and worse you likely busted out a bunch of fuses on the dead 4runner as well. The main fuse box is located to the right behind the battery. These are easy to check (pliers or fuse puller, a flashlight and look for busted wire) and easy to replace. In this situation I would track down the busted fuses, and it might only be one or two, and you can even swap out a less critical system to give a test start. You'll likely have to pull out the battery and go find an auto repair shop - most of the chains will check a battery for you (call and check though) and also get those replacement fuses. You'll be able to hopefully get back on the road quickly, at the cost of a new battery.
Note: The bad news is that you might have also cooked sensitive electronic bits like the ECU, or the wiring harness, or melted something close in the circuit but it's the fuses job to prevent that. The jumper cables might also be shot, but you didn't report the usual bad indicators like smoke, fire or the cables fusing to the car, so I'm willing to speculate it's just a few fuses and a very well done battery.
I should also note that the donor battery likely got very hot and you certainly shortened it's life as well.
posted by zenon at 11:29 PM on January 1, 2019 [4 favorites]