Unscientifically? Not to be rude, but if not scientifically based, then what are your statements about electrical components based on?
Are you just assuming this, or do you have some evidence or personal experience to back this up with? I’m asking because I want to get to the bottom of getting factual answers to my questions, and I was pretty sure I already did. If you’ve got a cite or even anecdotal evidence to share, please do.
In no particular order:
Frozen battery = replace it. Do not pass go, do not collect $200.
Quality of jumper cables? Bigger is better, size does make a difference. I also have 4 ga. cables.
Batteries going boom! Anytime a battery is charged, some hydrogen is produced. If hydrogen is present in the correct amount and a spark is present then BOOM! I have personally witnessed two battery explosion in my career. One was an old battery possibly bad, a spark was introduced by the customer while screwing around under the hood, and BOOM! Customer was taken to the hospital. Second was a professional technician who disconnected a battery cable with the key on. Spark jumped, hydrogen exploded, and part of the top of the battery decided to leave town. This was on a two year old car so I assume that that the battery was good. In this case all the technician had to do was change his shorts. Call me chickenshit, but I make both negative connection to the frame/engine.
You are correct about the complexity of a modern car, but IMHO you are incorrect about the end result. Cars are way more reliable now then 30-40 years ago. Particularly in electrical systems.
Discussing your truck in particular. The generator is probably capable of producing 25 A. My 2005 car has more electronics than you can shake a stick at, and the alternator is rated at 180 A (In testing it produces over 200 A).
Now let’s assume we are going to jump start a car, that requires 100 A to be drawn from the donor car. In my case, it will require about 60% of the rated output of my system. Your truck? 400% of it’s rated output. Which system do you think is being stressed harder?
Is there a risk to a modern car? Sure there is, but as I said in my first post
IMNSHO assuming that the cables are connected correctly, the risk is so low as to be not a concern. I am much more concerned about the guy connecting the cables than I am about the car’s electrical system.
Rick- can you suggest some good locations to ground to (Especially in a Ford E-350)? I always seem to have a hard time finding a good spot lately. Also, does it have to be bare metal?
No. All I was referring to there is the complexity of the system - there is very little to go wrong as far as a “jump start”, because it is so simple - far less to go wrong. Certainly, cars are much more reliable today, but that isn’t at issue here.
I’m just sayin’ - Figure a higher end late model car costs what, $50,000 or more? Say $30,000 for a “nice car” - if you have ever had serious or intermittent electrical problems with a car you’ll understand why you wish to avoid these if at all possible. When cars were simple, a “jump start” had no possibility of really hurting anything if performed correctly - there wasn’t anything to hurt - Today, with so many myriad critical low voltage/low current computer controls and individual parts rated at the margins of the design, I’m not so sure. It shouldn’t hurt anything, but I would avoid it unless absolutely necessary.
Could you please convince my dad of this?
We carry jumper cables in both the car and truck. I don’t go looking for opportunities to use them, but if I encounter someone who needs a jump I usually give it.
My dad invariably freaks a little whenever he hears about me doing this.
I carry them as well, at least in the wintertime. Or used to - the portable charger/air-compressor units work pretty good. If you really want to make someones’ day, bring along a good used (at least better than what they are trying jump!) battery as a donor! Mostly, I find people (in the wintertime) who are running on the last legs of the battery if not the whole car. When a car is in poor tune, it can be tough to start - starters and the battery are designed for only momentary use - the engine should pop off immediately. So many times a jump start is of little value to the stranded car.
Interesting reading here. By coincidence I had to jump start my girlfriend’s car yesterday. I was not aware that connecting the black lead directly to the dead battery was considered bad form. Certainly the car handbook makes no mention of it, and simply says to connect in the order red then black, dead to charged in each case. Was I dicing with danger by doing this?
So if not to the battery, where should you connect it? Any convenient exposed metal in the engine compartment?
Incidentally, I treid and failed to jump it off my neighbour’s car – no joy at all. I had to buy a new battery and jump it off that until I can get the new battery installed. Why do they make it utterly impossible to install a new battery yourself on modern cars? It appears that to fit the new battery you have to undo several clamp bolts which you can barely see, let alone get at with standard workshop tools. 
Seems to me that with the donor car running the radiator fan would vent any hydrogen immediately away from the car’s battery. Especally with the hood up and fresh air available.
The recipient’s car I would be more careful with. A charging battery will produce hydrogen gas. (You can see the bubbles when the low battery’s charging. This should be dealt with much more care.
Sorry, I missed your post earlier.Usually there is a bracket or boss on the engine that can be accessed and clamped to. If you can see where the battery ground strap attaches if you can clamp on that it is perfect. Painted surfaces are no good, as paint insulates. There may be treated surfaces that look painted but conduct electricity.
Colophon yes you were running a risk. Not as great as Russian Roulette but greater than the odds of you winning the PowerBall. Lots of people jump start cars by connecting both cables to the battery. Lots of people don’t have the battery explode. But when a battery goes boom, it can spay acid all over the front of your clothes, and in your face.
Jake You would think so, but experience tells us different. Also the guy driving the donor car probably has no idea about the condition of the battery in it. It could be gassing like mad, and since the car owner has not tested the battery, he would be unaware of it.
The very first automotive instructor I worked with used to say this about following procedures when jump starting / charging / servicing batteries.
Here’s where I believe the confusion exists. Say your jumping a dead battery and it takes a few minutes to get the dead batt. sufficient charge to start the disabled vehicle. If either batt. is likely to produce flammable vapors, it’s the one being charged. Now, if you have both jumper leads attached to the posts of the recipient batt., then when you remove one or the other, it’s probable that arcing may occur, igniting any vapor present. However, if you have the ground attached at some point away from the batt., and disconnect it first, it will dramatically reduce that probability.
So the danger exists, not in the initial attachment of the jumper cables, but rather, when they are being disconnected. Make sense?
Actually you can get a spark either when you attach the final cable, or detach the first cable.
Thanks, Rick!
Of course you can. My point is that the potential for explosive vapor to be present is more likely after the current tranfer has had time to warm the electrolyte in the discharged batt.
Thanks for the info. I think I will go get some and now I know what to get.
Frozen battery? Woudl this be the battery has gone dead and had time to freeze? I mean, the battery sits there in sub-freezing temps all winter and I assume it’s never “frozen”??
The electrolyte in a battery is sulphuric acid. H[sub]2[/sub]SO[sub]4[/sub] When charged all those SO[sub]4[/sub] ions are floating around in solution. That causes the freezing point of the battery to go down, way down. Kind of like anti freeze.
As the battery discharges the sulfur is deposited on the plates, and the freezing point of the battery rises. If the battery gets discharged enough, and the weather cold enough, you can freeze a battery just like an ice cube.
All I know is, the first time I tried to jump-start my car from my wife’s Volvo V70, it took me forever to find the battery. Finally, feeling like an idiot, I looked in the manual. It was in the back cargo area, beneath the floor, under the spare tire. There are terminals under the hood for jumper cables, but no battery.
Yup.
the good news is that by having the battery back there it prolongs the life of the battery.
Depending on which year V70 you have make damn sure the plastic cover over the battery is back in place, or the red plastic cover is back over the positive terminal. If something metal comes in contact with the positive terminal, bad things can happen.
A friend of mine related the story of how, back in the 70’s - well before cell phones - an all-nighter kegger in the sticks resulted in one of the partygoers cars battery dead, after playing the 8-track all night or whatever. Nobody had any jumper cables. What to do? Car bumbers weren’t made of plastic yet, so he had the good car pull up close and touch each other, making the negative ground/earth connection. Then, he used the now empty keg of beer, and a tire iron in series to make the positive connection. McGuyver would have been proud I’m sure.
I’m impressed. Even more so when you consider they figured this out hung over.