It's not any safer insofar as my alternator diodes are concerned.

Please explain, in detail, how what you say above is true.

Running the negative jumper to a grounded place on the other vehicle is no different than putting the cable on the other vehicle's negative battery post (assuming a good negative cable connection at both ends).

You are not BYPASSING their battery(ies) at all, merely moving a potential "spark" farther away from a potential source of flammable (explosive) gasses.

Sorry, but I'm not buying into the assertion that it makes it "safe", other than to avoid a potential battery explosion.

Again, it's not any safer for my alternator diodes.

Explain?

Pop

 

I LOVE THEM because you don't have to worry about overheating the battery.

 

I am embarrassed to say that only after purchasing and reading the instructions from the CTEK 4.3 charger I just bought did I learn that the reason folks are advised not to connect the negative jumper to the dead battery (or which ever is the last battery you connect to) is to avoid the spark caused by that connection potentially igniting any gases from the battery. So they tell you to connect to a bare metal surface away from the battery...and not the negative terminal on the battery.

This was news to me...

 

Yep, that is reason.. to keep the sparks away from the battery and the gases..

 

I enjoy helping people out, but given the complexity of modern vehicle electrical systems and the expense of repairs, just don't feel comfortable "jump starting" another vehicle. For one thing, there's no way to necessarily diagnose what the problem is accurately in a few minutes. Usually the no start situation is unrelated to the battery, but it has been neglected along with everything else, too. Might as well be trying to jump start a frying pan.

If it's wintertime, it's possible the battery electrolyte is frozen, for example. A fully charged up battery is good to go at thirty below, but a dead battery will freeze and may explode. Batteries with low electrolyte have the plates exposed and can also explode.

One way around this is to carry one of those portable jump-pack deals.

 

I bought a brand new "jump pack deal" a few years ago. Used it monthly to jump my lawnmower. It worked great for two years then the battery inside it refused charge. Very handy but will never get another one again. Bad experience. I think it was an Eliminator brand.

 

I wouldn't let one bad experience dissuade you from the concept of jump packs. After all, even tow truck drivers use jump packs. They are more convenient than maneuvering a tow truck around to be within a dead vehicles reach of cables.

I bought a "Professional" jump pack more than a dozen years ago. At the time it was Made in the USA, manufactured by Century MFG. It still works great today, more than a dozen years later. I think a lot depends on the quality one buys. The old adage "you get what you pay for" still holds true. I paid over $300 for mine at the time, but I just now found something similar (albeit different labeling and more than likely now made offshore) for only $266.00 on Amazon.

Here is a pic:





I've used this thing to start EVERYTHING, including my 7.3L truck, (before I switched to AGM batteries and have never had a dead battery since). Get a good one, keep it charged, and it is worth it's weight in gold.

 

Yes, Pop, I paid for a new alternator after jump starting some stranger that way in the ski resort parking lot. I will never do it that way again. Noticed that my van was not charging during a blizzard 100 miles from home... Back then AAA would put my van on a flatbed (it just barely fits under 15' overpasses) so I road home in the cab of an IH with a 7.3L. Now AAA calls my van an rv and won't tow it without an extra charge under my Premium Membership.

 

Tim and Pop... please explain more.

I've always tried to be a good Sam, and have jumped started a fair number of disabled vehicles with my current truck over the last 15 years that I've owned it, as well as with my previous trucks.

In all instances, I've always left my engine running. Oops? I've never lost an alternator... well, let me take that back. In my 1963 unibody F100, I lost a voltage regulator, but it was 1983 when that happened, so it was already 20 years old.

I don't know how I managed to jump start as many vehicles as I have with my source vehicle running without damaging an alternator, but it looks like the planets of dumb luck and pure ignorance aligned in my case, because I had no idea until this thread that this is considered by some to cause problems. I'm still not convinced, though.

In fact, what I have done with my 7.3L is kick up the Auxiliary Idle Control box to "Charge Protect", which elevates the engine idle to spin up my dual alternators to produce a constant 14.2 volts. The idle speed is typically between 1,200 and 1,350 RPM when in the Charge Protect mode. While running in that state is usually when I have the other driver start their dead vehicle that I've hooked up to mine.

From both of your reports, this sounds like a recipe for blown diodes and alternator replacement? Can you guys please explain more? I had no idea that truck alternators were that sensitive. I understand that jump starting a dead vehicle is a high current demand, but so is a hydraulic liftgate, drill rig, bucket lift, box crane, or any number of other high current electrical upfits and accessories that a work truck is expected to deal with. Heck, I imagine that the stereo systems some kids blast the block with have heavy current demands also.

If the engines had to be off all the time to deal with these high current electrical loads, then that could be quite inconvenient, and might also lead to more dead and drained batteries. I need some further education on this, because my past experience (spanning decades) has not managed (yet) to encounter an alternator failure based on jumpstarting another vehicle while mine was running.

 

Step 1,I charge the low battery for 10 to 15 minutes.Step 2, shut my truck off & let them try to start the truck with low battery.If wont start then evaluate connections & go back to step 1.

 

Since I missed this thread when it started 4 years ago I'll chime in now.
How many people know this trick?:


Back in the muscle car days when the cars had steel bumpers and high compression engines that would draw some serious starting amps we would sometimes butt the bumpers up tight and use both cables in parallel on the positive terminal. You could start any car using cheap cables this way.

 

Y2KW57: Pop's the brains here. I can just state that following that jump start, my alternator which was only a few months old (a replacement by Ford under warranty after the 4x4 conversion - welding frame with battery connected?), and it failed after a jump start in the ski resort parking lot.

I don't know the "why" but I do know the "how": Snow storm at night. (Obviously no moon.) Hwy 88 down from Kirkwood to Hope valley. First the radio fails, then the windshield wipers, (trying hard to get down off the Carson Pass), then the electric fuel pump fails (IH runs their 7.3L with a mechanical cam driven fuel pump for a reason?), then the lights, then coasting to a very dark stop. Then flares to avoid being hit by a car or taken out by a snowplow.

The jump start and the alternator failure may only be coincidence, but I don't want to repeat it.

 

A buddy of mine said he used a variation of this after a big all nighter out in the sticks. Maybe they had plastic bumpers, I dunno. No jumper cables. He used the empty Keg and a tire iron.

 

AKA same reason you are told to shut off engines in gas stations and phones on planes.

Nobody does it yet you don't see planes coming down and gas stations set on fire.

Also, same reason your ladder has no less than 4 warning labels.

 

Thanks Tim, for "jumping" back in to explain your circumstance. I'm not entirely convinced of the correlation, and am thinking your stated possibility of "coincidence" may be more the case.

Pop, I was hoping to hear more from you about an explanation of your assertion that alternator diodes are more likely to pop if the booster vehicle is running when giving the disabled vehicle a jump start. You say that you turn your booster vehicle off when jumping the disabled vehicle. This is the opposite of what Ford recommends in the owner's manual. Maybe Ford just want's to sell more alternators, but my experience leaving my engine running as a booster vehicle hasn't harmed any of my alternators yet. Do you think there might have been another cause for your popped diode?

Here is what our 2000 Model Year Ford F-250/350/450/550 Owner's Guide instructs us to do when jump starting vehicle, found on pages 164-168:

1. Use only a 12 volt power supply to start your vehicle.

2. Do not disconnect the battery of the disabled vehicle as this could damage the vehicles electrical system.

3. Park the booster vehicle close to the hood of the disabled vehicle, making sure the two vehicles do not touch. (Ford's bold emphasis, not my own). Set the parking brake on both vehicles and stay clear of the engine cooling fan and other moving parts.

4. Check all battery terminals and remove any excess corrosion before you attach the battery cables. Ensure all vent caps are tight and level. (Oh so nice not to have to do any of step 4 with AGM batteries... but I digress).

5. Turn the heater fan on in both vehicles to protect against any electrical surges. (Could this be the step you need to do instead, to protect your diodes without draining your booster batteries while starting the disabled vehicle?) Turn all other accessories off.

Then there are a couple of pages of diagrams about how to hook up the cables to the batteries and a separate ground point on the engine. I won't bother retyping those, because this thread has already covered the topic of the spark on the negative battery terminal connection igniting the localized cloud of explosive gasses hovering above a lead acid battery, and those dangers are not in dispute. What is in dispute here is whether or not the engine of the booster vehicle should be running or shut off when jumping a disabled vehicle. Ford continues at the top of Page 167...

Jump Starting:

1. Start the engine of the booster vehicle and run the engine at moderately increased speed.

2. Start the engine of the disabled vehicle.

3. Once the disabled vehicle has been started, run both engines for an additional three minutes before disconnecting the jumper cables.


So as I read this, not only should the booster vehicle be running when jump starting a disabled vehicle, it should be started first, and both vehicles should run together for several minutes before disconnecting. To me, this makes more sense than jump starting a vehicle from my batteries with my engine off. But maybe this makes more sense to me because it is what I've always done.

If there is a new and better way to do it (besides my convenient jump pack, which I don't always carry), I'd like to learn more about why deviating from Ford's recommendation may be better, even if following all the steps, including turning on the heater fans to both vehicles.