Anyone had to jump 12v battery?

As I understand the Leaf ... the 12v battery must be charged (have enough capacity) before the main ~400V battery pack can be charged. If the ~400v battery pack is too low to charge the 12v battery and the 12v battery does not have enough 'juice", the 12v battery must be charged first (before ~400v pack can be charged).

Under these conditions the 12v battery can be "jumped" from another 12v car battery or a battery charger (110v, etc).

Has anyone had to do this?

It's actually a little worse than this. You can have a full main pack, and still run the 12v battery down, requiring a jump to operate the car. The 12v battery is charged when the car is running, or every few days if the car is left off. Leaving lights on is supposed to be able to run it down before the recharge cycle happens on it's own. I haven't done it, but I'm sure someone has or will.

dznit said:

As I understand the Leaf ... the 12v battery must be charged (have enough capacity) before the main ~400V battery pack can be charged. If the ~400v battery pack is too low to charge the 12v battery and the 12v battery does not have enough 'juice", the 12v battery must be charged first (before ~400v pack can be charged).
Under these conditions the 12v battery can be "jumped" from another 12v car battery or a battery charger (110v, etc).
Has anyone had to do this?

Click to expand...

No, of course not. That fantastic PV panel on the LEAF keeps it fully charged at all times. :lol:

At least the process isn't quite as complicated as boosting a dead Prius battery. You do have to get under the hood, and that means popping the hood latch, which means getting into the car, which means using the manual key hidden inside the key fob if the car is locked. But with the Prius you then realize that the battery is at the back of the car, and the manual key doesn't work for the hatch. Fortunately there is a trick. The Prius has a hard-to-remove plastic cover over a fuse panel under the hood, and if you can manage to get that off there is a +12v terminator directly connected to the battery.

Thankfully, the LEAF battery is sitting right there in the open under the hood.

Ray

When charging the LEAF's 12v battery, is it recommended
to disconnect the 12v Ground first (and while charging the 12v battery)?

I've never seen a recommendation like that; in fact the opposite is always stressed. You should never connect directly to the negative battery terminal, but instead to some vehicle ground, after connecting to the positive terminal. I think the concern is sparks in the neighborhood of gasses from the battery.

Ray

For the LEAF (and really any other car), you hook up the terminals is this order: Bad battery positive, good battery positive, good battery negative, bad battery car ground (like the frame).

Never connect to the negative terminal of the bad battery, your completel a circuit and the bad battery will loose juice this way (your trying to give it juice!). The connection to the good battery negative terminal prevents the battery from exploding.

Owners manual page 6-9, 6-10, 6-11 show jump starting the 12v battery the same as any other ICE 12v battery. Only warnings about doing it while charging the main pack (Don't).