So, for Christmas, I got this car jumper that apparently jumps cars by reverse charging your battery through the cigarette lighter (car outlet). You stick it in the lighter, and it charges the battery of your car. After your car is started, it proceeds to recharge itself through the same outlet. They call it "MightyJump."

However, I have been told that it is bad or dangerous to use this type of thing on certain cars. Does anyone know if this'll work on a 2001 Ranger with a stock battery?

 

The 2001 Ranger wiring diagram shows the Lighter or Power Point plug to be fused and Hot all the time, so not on the key switch.

This means it should have 12v all the time.

The Mighty Jump, and other similar products are NOT for "jump starting" an engine, they, and the wiring in your vehicle, do not have and can not carry enough amps for that.
What they are for is to trickle charge a battery that has been drained by leaving a light on or similar "oops" issue.

You plug it into the cigarette lighter socket and then wait for 10 to 15min., the longer the better, unplug it and THEN try starting engine.
DO NOT turn on the key with this type of device connected.

Before using I would test it's voltage, some have reported as much as 30vDC which could fry some electronics in a vehicle, it can be as high as 15vDC but I would be concerned if it was higher.

If car battery is bad or the cars charging system was the reason for the dead battery then Might Jump won't help, simply not enough amps to replace car battery.

So for the specific "oops I left the lights on" this could be helpful.

And yes, after engine is started and charging system is working you can plug the Mighty Jump back in to cigarette lighter socket to be recharged.

Most newer vehicles have "battery savers" that will cut power after 20 minutes or so to prevent the dead battery issues with leaving something on.

 

Wow, thanks- I'm glad to have someone who really knows what they're talking about.

Though I can't test the voltage right now, I'll do it as soon as I can.

 

Yep- it's 12 volts DC, so it should be relatively good.