12v battery disconnected while driving?

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fgoh

New member
Joined
Sep 2, 2015
Messages
1
Today, after arriving at work as usual, I parked, hit "off" button...& bam! everything in my Leaf 'died'--couldn't re-start, no radio, no lights, couldn't pop-open the charge port, fob didn't work, etc., nothing worked on the car, except there was a soft high pitched sound that could only be heard inside the car. Battery charge was at about 60% right before I hit the "off" button. So, dug up the manual & called Nissan emergency (I'd heard the service was good but still have to give Nissan kudos as I was quickly connected to a real person). While talking to the rep, I popped the hood to look around & lo-&-behold, the negative terminal on the 12v battery was disconnected! Haven't opened the hood on this car since I got it (zero maintenance ownership aspect totally rules!), however I did take it to local dealer for regular service about 2 months ago & can only conclude they didn't fully tighten the clamp back-on after servicing. That service (with Buena Park Nissan) was a headache--among other things they misinformed me about repairs, didn't re-charge my car nor do all the recall fixes, but all that's another story. Anyways, back to my battery experience--so, I reconnected the terminal & everything came back! Did a short test drive, the radio stations had to be reset but otherwise all seems ok.

So here's what I'm wondering--it's possible & somewhat likely the clamp came off while I was driving rather than right when I parked, which means the Leaf can run even when no 12v battery? Has anyone experienced this? With an ICE I've read that if the 12v disconnects the car can continue to run but the alternator would fry the electronics. Since DC power & no alternator on our Leafs, that would explain why all is still well with car electronics? Any feedback would be appreciated as I'm also trying to decide if I need to take the car in (not to Buena Park Nissan tho'!) for a checkup.
 
fgoh said:
So here's what I'm wondering--it's possible & somewhat likely the clamp came off while I was driving rather than right when I parked, which means the Leaf can run even when no 12v battery? Has anyone experienced this? With an ICE I've read that if the 12v disconnects the car can continue to run but the alternator would fry the electronics. Since DC power & no alternator on our Leafs, that would explain why all is still well with car electronics? Any feedback would be appreciated as I'm also trying to decide if I need to take the car in (not to Buena Park Nissan tho'!) for a checkup.

I think you correctly identified the problem, and I also think there's nothing more you can/should do other than tighten that terminal/lug. While the 12v battery is very important in the Leaf when off, I believe it's main on function is to engage the main battery pack; after that, the car provides a stable 12v source (and charges the 12v battery).
 
A similar thing happened to me. I came out of a restaurant after breakfast and my Leaf was dead. I called road service and they sent out a tow truck.

The driver jumped the battery and I drove to the closest Nissan dealer. When I shut down the power it was dead!. They put in a new battery under warranty.
 
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