Skip to content
View in the app

A better way to browse. Learn more.

Ultimate Subaru Message Board

A full-screen app on your home screen with push notifications, badges and more.

To install this app on iOS and iPadOS
  1. Tap the Share icon in Safari
  2. Scroll the menu and tap Add to Home Screen.
  3. Tap Add in the top-right corner.
To install this app on Android
  1. Tap the 3-dot menu (⋮) in the top-right corner of the browser.
  2. Tap Add to Home screen or Install app.
  3. Confirm by tapping Install.

Jump starting someone elses car

Featured Replies

I don't know if I am blind but I would have sworn you are suppost to leave your car off while you jump someone elses car who has a dead battery to protect my alternator because I could damage a diode. Is this correct?

No. Connect the cars then start it up. If that doesnt work rev the engine to about 1800 RPM where the alt starts putting out power. You can start it with the car off, but if you have been trying a while you may need a jump start yourself.

 

 

nipper

  • Author

i thought it was bad for the alternator diods thats why i ask.

With the advent of all the electronics stuffed under the hood since the mid - late 80's, the basic of jump starting have changed.

 

Whenever possible, use a portable starter kit. These are the jumpstart units most tow trucks use these days when dispatched. They are separate and have little chance of overvoltage or frying the 'jumped' vehicle electronics.

 

In the event one is not available, attach the cables to the donor vehicle's battery positive, then the dead vehicle positive, the donor negative at the battery, then last the dead vehicle motor for ground.

Start the donor and let it run for 20-30 minutes to charge the dead battery.

Shut off the donor vehicle and try to start the dead vehicle. In the even it does NOT start, you should not go further.

Having the donor run while attempting to start the dead vehicle can damage the donor's Alternator or cause a voltage spike which can damage electronics in either vehicle.

 

It's a wonderful thing to be a good Samaritan, but at what cost.

With the advent of all the electronics stuffed under the hood since the mid - late 80's, the basic of jump starting have changed.

 

Whenever possible, use a portable starter kit. These are the jumpstart units most tow trucks use these days when dispatched. They are separate and have little chance of overvoltage or frying the 'jumped' vehicle electronics.

 

In the event one is not available, attach the cables to the donor vehicle's battery positive, then the dead vehicle positive, the donor negative at the battery, then last the dead vehicle motor for ground.

Start the donor and let it run for 20-30 minutes to charge the dead battery.

Shut off the donor vehicle and try to start the dead vehicle. In the even it does NOT start, you should not go further.

Having the donor run while attempting to start the dead vehicle can damage the donor's Alternator or cause a voltage spike which can damage electronics in either vehicle.

 

It's a wonderful thing to be a good Samaritan, but at what cost.

 

The only time a module or alt gets blown up is when people connect to a running car (modern cars), and that was never in the procedures for jump starting a car. It doesnt pay to rush things.

 

 

nipper

I had to look for one for a lady friend. They have a gizmo that goes from cigarette lighter to cigarette lighter. Hard to screw up. But you gotta have patience. In some cases you may need to have the key on (to make the lighter "hot") so it may never charge.

 

I myself have the big blue Jump-n-carry 660 I believe. The best i've found. It'll start 20-30 dead cars on one charge when newer, and diesel cars. If it's charged and doesn't start it the car is dead. ALso works to power my winch.

 

Remember those bizarre batteries they were marketing that had like a different "bonus" section where you could open the hood, throw a switch, and get an extra start out of them. Saw them on TV, never seen one in person. Can't imagine they worked well or that folks would buy them.

the cig lighter things doesnt work, its a HUGE waste of money. At best that circuit is ten amps. ten amps wont even get the straters attention.

 

 

I have a nice bridge for sale that i would throw in that lighter thing.

 

 

nipper

the cig lighter things doesnt work, its a HUGE waste of money. At best that circuit is ten amps. ten amps wont even get the straters attention.

 

 

I have a nice bridge for sale that i would throw in that lighter thing.

 

 

nipper

 

It's supposed to charge the battery - like over lunch or something. I figure it's like a 10 amp charger. Not fast but hard to screw anything up.

 

Not that I'd use one myself. It just doesn't sound like it could hurt anything.

It's supposed to charge the battery - like over lunch or something. I figure it's like a 10 amp charger. Not fast but hard to screw anything up.

 

Not that I'd use one myself. It just doesn't sound like it could hurt anything.

 

 

So you leave your car running for an hour or so while the other is charging? An invitation to theft. Also if someone isnt patient they can fry the thing. usually when you need a jump start you discover it when you have to be someplace.

 

 

nipper

So you leave your car running for an hour or so while the other is charging? An invitation to theft. Also if someone isnt patient they can fry the thing. usually when you need a jump start you discover it when you have to be someplace.

 

 

nipper

heck no, i sometimes wake myself up in the middle of the night just to go out and see if i need a jump. i certainly wouldn't want to find out when i was getting in the car to go somewhere. :lol:

Please sign in to comment

You will be able to leave a comment after signing in

Sign In Now

Account

Navigation

Search

Search

Configure browser push notifications

Chrome (Android)
  1. Tap the lock icon next to the address bar.
  2. Tap Permissions → Notifications.
  3. Adjust your preference.
Chrome (Desktop)
  1. Click the padlock icon in the address bar.
  2. Select Site settings.
  3. Find Notifications and adjust your preference.