We had a nasty storm last evening… and all of our vehicles were obviously burried in snow this morning. I have an 87’ Land Cruiser that likes to go dead after letting it sit for a couple days. I only got it a month ago and it has been giving me grief ever since. I bought it as a beater car for the winter so I could garage my Avalanche. I found out quickly that I was killing the battery by leaving the ignition switch on ACC over night every night… I quickly learned to switch it to OFF and have not had too much problems with it since.
This morning I wasn’t getting anything upon trying to start it so I grabbed the truck, pulled it up to the Cruiser and tried jumping it. Here is the exact sequence of events and subsequent issues.
Pulled truck to cruiser and left it running. Attached cables to truck then to cruiser… Tried jumping cruiser to no avail. Nothing came from the jump so I hopped out to check the connections. Positive on Positive Negative on Negative check…
I noticed smoke coming from both connections on both vehicles, I tried pulling the cable off my battery and it burned through the protective rubber and snapped off leaving the bare wire still burning the rubber casing on the cable line. I tried removing the cable from the truck and the same thing happened, it burned through the rubber casing in the line and snapped off.
Here’s the weird part. I then tried starting the cruiser without the cables and it started right up?
Do I have a Stephen King mobile or am I doing something wrong? I’ve jumped the cruiser plenty of times… what gives today?
Too much current and too small of a cable.
Before they burned up, you managed to get enough amps into the battery to start.
Jumper cables come in three flavors
Very Crappy (cheap)
Crappy (not very cheap)
Good (very spendy)
For what you are trying to do, I would expect that you need to pay in the $50-$75 range for cables that will last.
I’ve been on this soapbox too often, but here goes again:
The vast majority of jumper cables sold are junk. Good ones exist, but you have to seek them out, and as previous respondant said, they are not cheap. Thin wire with thick insulation so that it looks “heavy duty”. This is actually detrimental, as that thick plastic provides thermal as well as electrical insulation. Hot thin wire has even higher resistance than cold thin wire, so generates even more heat.
Somewhere on the package will be the wire gauge. On cheap cables it will be in the fine print, and will be AWG (american wire gauge) 10 at best. Like most things measured in “gauge” smaller numbers mean larger wire.
You can’t start a cold engine with #10 wire. You can, at best, charge the battery enough over time so the dead car might start.
Actually starting a car requires at least #6 wire. Make that #4 if you live somewhere where it gets really cold. Make that #2 if the dead car is a diesel. Make it #0 or 2/0 if it is a diesel truck.
Places that cater to truckers sell heavy jumper cables. The auto parts chain with the blue and gold motif also does. Welding equipment dealers sell wire and clamps so you can make your own.
Your problem is that you’re not supposed to connect both terminals on the car to be jumped. You connect positive to positive, but then negative on the car doing the jumping to the engine block (or some other grounded section of the car) on the car to be jumped. By connecting positive-positive and negative-negative, you created a short circuit and the live battery forced electricity through the dead one.
I wonder if I should even bother having a mechanic look for a short in the lines… It would seem there is probably miles of electricals that couls be shorting something to ground. Oh and I did have a cheap pair of cables…
Oh hell yeah! That was one of the reasons I bought it, it’s not all decked out with leather, ultra sound proofiing etc…etc… It’s a hog! And it can pull just about anything I hitch onto it. I love it! I’m contemplating having the exterior body done to perfection and retoring the looks to full luster and using it full time. I get tons of complements on it.
The block and any grounded section of the car are electrically common with the negative post on the battery - in fact, the negative post on the battery is the reference ground for the entire car, given that there’s obviously no “grounded to earth” reference on a vehicular electrical system. There is absolutely no difference in terms of the circuit created between connecting your negative clamp to the battery terminal and any grounded chunk of metal on the car. The reason it is sometimes not recommended to connect the negative clamp to something other than the negative post is to avoid creating sparks in the vicinity of the battery - something to do with flamable fumes given off by the battery acid or something.
This is incorrect. Given a constant (or nearly so) voltage source like a battery, less resistance generates more heat. Think of it this way: Before you snap on the cables at all, there’s an air connection between the two batteries. Air has a huge resistance (effectively infinite, for most purposes), far higher than even the crappiest jumper cable. And the air between the batteries doesn’t heat up at all.
I’d be curious to know if there’s any actual evidence of this being a real concern. Even if a battery gives off a little hydrogen, it would be a fairly small amount and disperse pretty much immediately. And in the unlikely event that there were a high enough concentration to ignite, it’d be just one little poof of flame and go out. I can’t imagine that it would be any more likely to ignite a grease fire or anything that might actually burn in something like a sustained fashion than the spark itself would be. I dunno. I could be wrong here, but the concern as stated doesn’t make much sense to me.
I’ve heard this nonsense for years, often with scary stories (urban legend type) of what will happen if you do direct battery-to-battery connections.
Yet in 50 years of living thru Minnesota winters, and seeing a lwhole ot of dead batteries being jumped, I have probably seen less than a dozen cases where real people used anything other than a direct battery-to-battery connection.*
And I’ve never seen, or even heard of anyone who had a ‘hydrogen gas explosion’ while jumping a battery.
I suppose it could happen, but I’d bet being hit by a lightning bolt is more common!
(Heck, on most cars it’d be real hard to find a part of the engine block that is connectable that isn’t so dirty with grease, mud, or snow as to be a poor conductor.)
Allow me to correct this statement. It should read "It would be just one small explosion that although it probably won’t burn the car to the ground it will blow a hole in the top of the battery, and spray sulfuric acid all over the nearby area. This includes the unlucky guy holding the jumper cables. Sulfuric acid seems to be almost magnetically attracted to people’s eyes.”
Likely damage from an exploded battery include:
New battery
New clothes
Visit to the Dr. for your eyes
Trip to the body shop to repaint fender
You are. The last battery I saw explode threw a large chunk of the top of the battery about 20 feet into the air. It sent the guy that was standing there to the hospital due to acid in the eyes.
When the battery charges it generates Hydrogen. It also generates pure oxygen. Put a spark to that mixture and it will EXPLODE. Not burn, explode.
I’m glad to read that story. I’m another person who has always believed that stuff about hydrogen danger around a battery but I never heard about anyone actually getting hurt by an actual explosion. Fortunately, one story from a person who saw it happen is enough for me. (Jeez, I hope this doesn’t count as a friend of a friend kind of thing). I’ll take it for the case that disproves the hypothesis. And that’s all I need.
Of course, now I’m wondering if the cables I keep coiled up in my trunk could get brittle in the cold and snap inside the insulation if I pull them out to use them on a particularly chilly winter morn. I haven’t had a problem over the last seven or so years with occasional use, though, and these (as I recall) were decent but not super-high-end cables.
Your jumper cables burned because you got too impatient. When jumping from one vehicle to another it’s advisable to wait a few minutes, after hooking up the jumper cables, to allow the low battery to absorb some charge. If the low battery is in good condition, this won’t take long.
When you hook up the jumpers and immediately try to start the second vehicle, you are bypassing the low battery and send current directly to the starter motor. That means that your passing a couple hundred amps. through those jumper cables. Now compare the size of the wire in the jumpers to the size of the wire going from the battery to the starter, the cheaper the jumpers, the bigger the difference. There’s also the issue of the aligator clamps, most have little teeth to grap onto the battery post, or other point of contact. This is, in effect, the “weak link” in the circuit. This weak link cause more resistance and faster heat rise in the jumper wires.
So hook up the cables and then up the idle on the donor vehicle for a few minutes before attempting to start the other engine. This will avoid drawing all the required an amperage through the jumpers.
Here’s where the generation of gas comes from, as both batteries are accepting a charge it warms and generates the gas in both batteries. After the second vehicle starts, you should properly disconnect the neg. connection from it first. If you have made that connection to the neg. post of the low battery then there may be a spark right there where the gas is venting from the charging battery and BOOM. If you made the neg, connection to a point away from the battery, it may spark, but there’s no gas to ignite.
Remember, both batteries can be venting gas, but the low one is charging faster and more likely to be the danger.
If you have quality jumpers w/ heavy cable and strong aligator clip, such as you’ll find on a wrecker, or service truck, you may be able to skip the few minutes of charging, but w/ typical Wallyworld jumpers, you should do it as I described.
