Dead 12v battery, twice!

[voganni]

I've leased a new 2013 Leaf S with large charger option. Twice now, the 12v battery has been found dead, after one week, then two weeks of ownership. Calling the dealer produced no useful information. I have discovered that powering the Leaf off from ACC mode causes the battery to drain to stone dead in about 4-5 hours. This is not the infamous "double push" syndrome others have discussed. It is some kind of glitch in the 2013. Since I quit doing this (it was, both times, when I powered it up in ACC to check the miles on the charge, then giving ONE PUSH to power it off.

Since I have avoided doing this, the battery has remained fully charged for over a week. I've been monitoring battery voltage during the last week, and notice that it is a little higher when the car is plugged in, (after charge is done) than when unplugged. Note that the 12v battery only gets charged when the main contactors are closed, which is in ready mode, or during charging.

ACC mode is not your friend! Use it very carefully, and don't power the car down from this mode. Go back to ready, then off.

 

[planet4ever]

I have discovered that powering the Leaf off from ACC mode causes the battery to drain to stone dead in about 4-5 hours. This is not the infamous "double push" syndrome others have discussed. It is some kind of glitch in the 2013. Since I quit doing this (it was, both times, when I powered it up in ACC to check the miles on the charge, then giving ONE PUSH to power it off.

Sorry, but I expect you are seeing a close relative of the "double push" problem. Since you have an S model, there was nothing you could have looked at in ACC mode -- the dash would have been dark, and only the audio system display and/or climate control display might have been lit up. So you were not in ACC mode, but (probably) in ON mode, i.e. dash lit up, but no green car with arrows. Now let's talk about that "one push". Did you have your foot on the brake pedal when you did it? If so, the car would have looked like it was shutting down, but it would then have powered itself up to READY state, perhaps after you got out and shut the door.

See my complete mapping of the transitions.

Ray

 

[voganni]

OK, guess I was wrong about the verbage, but not the glitch. In ACC my car lights up the audio screen which is very obvious. I did a double-push to put it in ON mode, checked the charge, then one push, with brake off, to power it down. No door chime, fob in my pocket (second instance), dash dark, car apparently off. Came out about 3 hours later and 12v battery was at 9 volts. Time before, it was at 7 volts and wouldn't power up the car.Totally freaked out the computers and I had to disconnect the battery (after charging it up) to reset the system before the EV and brake failure lights would go off.

The first time it happened I had left my fob in the car, as well as my phone, with bluetooth enabled. I thought maybe this had caused the car to power itself back up, but no. Did it the second time with nothing in the car.

Reading other owner's posts, I think it is the same issue. They take it to the dealer, everything checks out OK, dealer replaces the battery, which is probably not bad, and this sneaky problem is still there.

BTW, if I go from ON to Ready with a single push with the brake depressed, the transition is instant, with no powering off and then on. The dash merely shows the ready light, batt warning light goes off, and eco indicator comes on.

 

[TimLee]

... Note that the 12v battery only gets charged when the main contactors are closed, which is in ready mode, or during charging.

ACC mode is not your friend! Use it very carefully, and don't power the car down from this mode. Go back to ready, then off.

You are correct that the 12V battery will only be charged when the main contactors are closed. But in addition to Ready mode, or during charging, 12V battery charging will also occur in the On mode when the 12V battery drops to a certain level. In the 2011 / 2012 the fact the 12V battery is charging in On mode will be indicated by flashing of the center blue LED. I'm presuming the indication is the same on the 2013.
Your observation of shutdown from ACC mode resulting in dead 12V battery is interesting. You could have spotted something of interest that Nissan should research further. They have experienced a lot of issues with 12V batteries, although their response to the issue on the 2011 / 2012 following questions at the January 8th townhall meeting was basically no response. They consider the 12V battery failure rate within normal limits.
In my opinion, use of ACC mode in the LEAF is a bad idea in general. You should at least put the vehicle into ON mode where the main battery will keep the 12V charged from the DC to DC convertor if the 12V battery drops too low on voltage.
It is possible that putting the LEAF in Ready mode (but making sure it is in Park and parking brake is engaged) may be better than On mode. When the car enters Ready mode, several people have observed that the DC to DC converter does bring up voltage to something in the low 13V range, for at least some period of time, although not as long as it should to actually assure the 12V battery is fully charged.
If you use On mode, it apparently does not do that. Only starts charging the 12V battery after the voltage has dropped to some threshold value.
In light of that, I have begun putting the car in Ready mode instead of On mode when listening to the car radio for extended durations. I thought it might result in more drain from the main battery pack, than On mode. But I have not noticed any difference. The drain on the main pack appears to be the same for Ready and On (have to make sure HVAC is off in both cases).
Quit using ACC mode. It is a bad unnecessary thing to do with the LEAF. :shock: :shock:

 

[voganni]

I have to agree with you about using ready mode instead of ON. I had a bluetooth phone call sitting in my driveway for over an hour in ready mode and not even a mile of range was lost!

I don't know about the 12v battery being charged in ON mode, it would have to close the contactors to do that. There is supposed to be a feature that will charge the battery every 5 days if the car is off and unplugged. Perhaps that feature also works in ON mode if the battery level drops low enough. I'm not going to test it! The Leaf is very unhappy when a power-up is attempted with a near-dead 12v battery. I hope this post and discussion can prevent some other unsuspecting owners from getting the dead battery blues! Thanks for your input Tim.