I have heard stories of people damaging the alternator by giving a jump-start. I have jump-started a handful of cars and never had a problem. I am just wondering how common this is.

I know a boost pack is a better option, but that is expensive if you want to keep them in multiple vehicles.

Never heard of it.

LOL! No!

Why is a "boost pack" which is a 12V battery in a box better than a 12V battery in a vehicle?

Not that big of an issue for a short amount of time.


It will destroy a bike or a lawnmower though! ??

Standardize your connections, ie, use the RED  clamp on both positive battery terminals, and use the BLACK clamp on both battery negative posts, and you will NOT fuck anything up.

Nope.

No, never known anyone first hand...but I did learn when I was younger to always hookup your own cables. (I was jumping someone's car and the hooked their end of the cables up backwards.) smoked the cables for a couple seconds. My car was fine for years after that.

My father in law says "you should never jump start someone, not worth the risk."

I've seen a dipshit kill an alternator by hooking up wrong way round.

How would that even work?

You are just adding another battery to the car.

I don't see how that's an issue.

Now what I have seen in that some of the older Outboards I have worked on if you are running and then disconnect the batter while the engine is running you blow the rectifier/regulator.

Not yet, no.  I didn't even know it was possible to be red/black color blind.

two vehicles with metal bumpers touching each other can short out an alternator.

I have done this once. about 25 years ago.

Red to positive and Black to negative.  Probably best if you did it yourself instead of trusting someone to know positive from negative.  In the dark....well, get a flashlight.  You could burn out a diode (back in the old days) by hooking it up incorrectly.

Aloha, Mark

No, but I have witnessed quite a bit of derp from people I've stopped to give jumps. I always insist they hook up "their end" themselves. One young man was trying to put his positive end onto the big-ass red plastic cover over his battery terminal. I was glad he knew that red went with red, but still had to explain to him how electrons don't travel through plastic.

If I'm jumping someone else I don't hook both clamps up to my battery, I use a piece of bare metal for negative. Never blown up an alternator either.

lolno

I did once jumpstart a 7.3 diesel with a 1.8T; almost stalled my fucking car when he hit it

I don't touch anybody else's shit anymore, and tell them to call a tow truck.

My neighbor's truck was a dying piece of shit for months and I helped by jumping it to get it going.  It died finally a week later (after being driven around a bunch) and he joked about me killing it later.

I have had people with computer problems that show up 8 months later saying something I did removing their viruses their (or their kid's) porn surfing habits got them were my fault.

"Hey, you touched it once, and I am too stupid to understand what you did, it must be your fault!"  Like a big old cargo-cult of blame for the drooling primitives.

Don't need that hoseshit in my life. So I just lie and say "I don't have cables" or just say "No" if they have their own.

That said, a booster pack has been one of the most useful tools I own for family and the GF.

This.  At least not without doing something stupid.

That works right up until a very good friend needs a jumper.  My truck lived through it just fine.  It is best to start with both vehicles off.  Hook up cables. Start and run yours for a minute or two.  Then start the dead vehicle.

Because it's portable, and I can jump my own car without relying on anyone else.

I carry a jump battery and jumper cables in both my vehicles.  Always have options. 

Yes I have ruined an alternator from jump starting, 20 years ago.  It was dark out so I left my car running with the headlights on . It sparked pretty good......besides that I made the correct connections. On my drive home the wipers got slower and slower, headlights got dim. Tested it and found my alt. was bad

A dead battery puts a higher charging load on the alternator and drives up heat.

Also, I have absolutely lost an alternator just after jump starting another car. This was about 16 years ago and was not due to connecting things the wrong way.

Most people just call that "blind".

No, but my college roommate fucked up his girlfriend's car trying to jump it with the leads reversed. Still won't let that dumbass live that down

nope,, have heard of people fucking things up because they cannot figure out the correct way to use jumper cables crossing them

I won't jump anyone...Just had a friend ask for that the other week, and I basically told him to call AAA.  Sure, risk is small if you know what you are doing, but it's just not worth it to me to risk fucking something up in my car due to someone (even me), not stopping to think.

Everyone is racist. 

Not me but happens all the time.
My sister blew her master fuse hooking it up wrong.

I destroyed an alternator in my 1996 Thunderbird that had a custom high output alternator for the sound system by jumping someone's vehicle.  After replacing that $700 bad boy, I never jumped another vehicle.  

I was even called an asshole by someone who asked me for a jump, even though I told them my reason for not doing it.  Sorry, but you leaving your headlights on is no reason for me to risk another $700 of my own money.

EDIT:  The last vehicle I jumped was my wife's car after she left her headlights on.  I don't care if I ruin an alternator jump starting her vehicle!  

Had a 1983 Honda Accord that ate the alternator both times I tried to use it to start something. Only vehicle I ever owned out of dozens that did that.I was a mechanic that jumped started cars and trucks all the time.So it wasn't being done wrong.

Just because you haven't seen it doesn't mean it can't happen.

First rule of jumping a car is leave YOURS turned off. It's the surge that can kill some alternator circuits, and nobody promised that some other derp hooking it up backward can swear on a stack of Motor Manuals that a diode in his old POS is proof against 500 amps.

Second, if the battery is dead, then the alternator hooked up to it is likely, too. All you do is run down your car even more, and then when you finally diagnose it correctly, you have the alternator trying to divert amps to charging the battery when it was never designed to do that job - charge it from dead. No, it never was. Why should it be, you aren't supposed to run the battery dead, it's pretty presumptuous to think they added extra capacity to it just for a once every ten years situation. If they can save a buck they will - don't even try to charge a dead battery under the hood.

Heres some math if its not too intellectually taxing: 140 amp alternator trying to charge a 800 amp battery. Nope, you DON'T get the full capacity, it's using at least 80 amps running the motor: electronic ignition, fuel injection including computer, fuel pump, injectors and sensors, then add A/C, dash, interior, electric steering, etc. You are lucky to get 15-20 amps left over. Divide that into the complete lack of 800 amps capacity, you get 40 HOURS of driving the car around to charge it back up. Not Idling it, no, it has to run over 1800 rpm to get the alternator up to speed working. That means you are busting it for a 40 hour duty cycle. It's no wonder that the alternator manufacturers and rebuilders all say their #1 failure is from a dead battery getting charged up after running the car all day ignoring the light on the dash.

Hook up the external charger and just stand back and watch the magic. Cheaper, too.

Do not, under any circumstances, try to diagnose the charging system by removing the positive cable from the battery. No. Not even. You just removed the 140 amps trying to go somewhere and the battery is the capacitor. So, now where's all that power going? It's sitting in the diode grid with no where to go except the weakest link - and that's a printed PC circuit board in the internal voltage regulator. ZZZZZPP and it shorts to ground. Happy now? Do not let Uncle Fred pull that 1950's dinosaur tech he played with back in the day with your car. His old beater had a 40 amp generator points controlled, with a 250 CCA battery. You have a 140 amp computer circuit controlled system with a 800 amp battery. What Uncle Fred may have done to his old lever action you do not want to try with your AR. Stand your ground and get someone who was at least 20 years old at the time your car was built. Uncle Fred isn't that guy and has NO clue.

For the most part just pay attention to the gauges and lights every now and then driving your car. If it is hard to start don't go 50 more miles down the road into a snow storm thinking "Oh it's ok." Clean your battery terminals at least every 6 months - they made the cells maintenance free, not the cables and clamps. If they aren't bright shiny clean you are setting yourself up for failure.

Lots of people finesse neglect, put off the obvious, have the exact wrong things done, and then go into blame everybody else mode with it all blows up in their face. Don't be those people. They lost the election. Make American Great Again, pay attention to the rules of working with alternators. Not Uncle Freds rules of what he got away with abusing low amp generators back in the adolescence of automobiles.

Really, considering what he did and how he learned it, do you want to take the advice from someone who didn't have the experience and education then to know what he's doing wrong? Put it this way, were all his smart ideas a big hit with his spouse back then, too. He was the smooth debonair ladies man of mystery? Uncle Fred? You really sure about that? No. He never had a clue either. He had to blow stuff up to learn. Ask your Aunt.

Don't let him blow your stuff up to learn about modern electrical systems. The average 20 something counterman working for a year knows more.

The rest of your post is spot on, however, the above sentence and really mess up some of the new cars unless a power source in used to keep the power to the car.

This and I have jumped off several class 8 trucks and a lot of other stuff too. I have however burned up an ignition coil on a 50cc scooter jumping it with my truck.

Or, you can just carry one of these in your car instead of jumper cables (lots of different brands. Just search "car jumper pack" on Amazon). They're the size of one of the larger cell phone battery pack chargers.

I tested alternators for a decade at a big remanufacturer. You'd be surprised how long modern units can sit at high output. I also tore down warranties and saw lots of fun heat and arcing damage on rectifiers 

In my experience whenever you start needing a jump start it's because your alternator or battery is bad.  If the battery is bad, chances are the alternator will be shitting the bed in the near future.

Possibly the reason some may believe jump starting kills an alternator.

What are you driving a Tesla?

My WRX has a 17 AH battery. 75 amp alternator soo, not 40 hours of driving to charge.

Never in my experience.

Drives me nuts when people advice to "take the positive cable off, if it runs, it's the battery" crap.  Good advice +50 years ago when cars came with 12 vdc generators, not 3 phase 120 VAC alternators.

Had some yuppie shitbag loose his mind when I refused to jump his POS Acura with the M-37 I was driving.

He did not seem to get it that "24 volts is bad for 12 volt systems".

Google is your friend.

https://www.youtube.com/watch?v=kVXf7B5UoI4

Alternators don't wear out at near the rate that batteries do. 

At least not anymore.

What a 28-year-old alternator sounds like when the bearings are almost ready to come out the back of the alternator.

https://youtu.be/X4u4m3ufJiY

Once I stopped and jump started a car driven by a Mexican chick who didn't speak much English. I assumed her red cable was positive and black was negative, and got smoke.

Turns out someone had installed a black cable for her positive and red for her negative.

I've done scores, maybe even hundreds of jumps for people over the years and never had a problem. I've always had cables and always helped people who needed a jump.

Another thing - you really should wear eye protection. I know this is GD and safety is for faggots, but THOUSANDS of people end up in the ER each year because a car battery blew up in their face. Something to consider.

No .

Yep. That's why they recommend the last neg connection to be to GND on metal somewhere not near the battery. So the spark doesn't ignite fumes over the battery.

So to sum-up this thread...

"If you do simple shit wrong, shit gets fucked up."

A.W.D.

What a piece of shit car.

Blew out some primary system board in a 1987 325ic by jump-starting another car back in the day.  About a $1500 part at the time.

I have. Old Nissan 720 pickup we had used a black cable for +12v and a black with red stripe for ground. First time I jumped it I didn't look at the terminals and hooked red to black-red and black to black and immediately popped the voltage regulator on the alternator. I put red electrical tape on the positive connection after replacing the alternator...