How to Jump Start an ICE with a Leaf

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How to jump start an ICE car with a Leaf? In the manual it says: "LEAF cannot be used as a booster vehicle because it cannot supply enough power to start a gasoline engine", which doesn't sound very encouraging.

Howeever, I came across a long discussion on this topic on There was a lot of different opinions voiced, many seemingly contradictory. In any case, I've paraphrased what I've considered the majority opinion.

I've followed these steps on two or three occassions and it has worked fine each time.

Extracts copied and pasted from


There's always a possibility something could go badly wrong. Wear protection for eyes and skin. You could die, you could destroy one or all nearby vehicles! You have been warned!


  1. LEAF is in Ready mode (green car with bidirectional arrows on dash).
  2. Be sure all unattached jumper cable clamps are not touching each other or anything else conductive.
  3. Connect the positive (red) jumper cable clamp to the positive terminal of the dead car's battery.
  4. Connect the other positive jumper cable clamp to the LEAF's 12v battery positive terminal.
  5. Connect the negative jumper cable clamp to the dead car's negative battery terminal.
  6. This is the final connection, connect the negative jumper cable clamp to the LEAF's DC-DC converter negative terminal. You can locate this by following the heavy wire from the negative battery terminal. [This cable meanders somewhat – see the arrow in the image below in a 2012 Leaf].

Allow at a minimum of 2 full minutes before attempting to start the dead car. If it doesn't crank fast, immediately stop and wait some more. If after 10 minutes it won't crank, you should throw in the towel; Something is wrong.

Always disconnect in reverse order, so once the dead car is running, disconnect the negative clamp from the LEAF's DC-DC.

Note: The LEAF's DC-DC converter is about as powerful as an alternator on any normal car, and should charge a dead ICE battery enough to start it in a few minutes. No need to "rev" the LEAF! (Putting high loads on the little battery without the DC-DC converter is not a good idea. In fact, The DC-DC is powerful and yet current-limited, and since it is liquid-cooled, it can handle high loads much better than most car alternators. Without having the LEAF in ready, you aren't going to get much across the jumper cables from the small battery alone.)

Jump starting an ICE car with a Leaf.jpg

The LEAF's DC-DC converter negative terminal marked with an arrow in a Gen 1 Leaf.