Putting in sun screen caused dead 12 V battery

[Jeffs231Leafp]

On my 2024 Nissan Leaf; While I was putting in my sunscreen ( black side out for snow/ ice ) I accidentally hit the emergency flashers. I did not notice that they were on. It was about 5 PM, my car was plugged in, on a timer for midnight charging. It was about 20 F at the time and about 16 F overnight. Next morning the car was dead. Got in with the driver side door key. So what I learned is that the 12 VDC battery does not charge when plugged in , unless you are actually able to charge. A quick jump from a sump pump battery backup battery in my garage and it started. Then pressing the timer override, It was then able to charge both the 12 V and the HV battery. But I am not sure if the timer was reset, due to the dead 12 V battery. BTW; The way I discovered it EV Connect was not giving me a charge status.

 

[k9spud]

So what I learned is that the 12 VDC battery does not charge when plugged in , unless you are actually able to charge.

Yup. And it's worse than that -- if the EVSE is plugged into the car, it slowly drains the 12V battery unless you're actually charging. That vampiric drain on the 12V battery is why I never use the charging timer feature and always pull the EVSE out of my car as soon as it finishes charging. I also like to blip the windshield wipers a few times before I power off the car after arriving home, as that triggers the DC-DC converter to top-up the 12V battery from the traction battery for a minute or two after each wiper blip.

Of course, I'm using a 2013 Leaf. I have no idea if they fixed any of this stuff in a 2024 Leaf.

 

[bruceha2000]

The topic title is VERY misleading but the information is good. Do not leave it plugged into the charging station after it is charged if you aren't going to drive it for a day or a few, no reason to waste electricity with the parasitic drain. But my wife has to use the charge timer feature because:
- We pay 4 cents/kWh less between 9 PM and 1 PM
- She drives 70 miles minimum 7 days a week and leaves at 6:30 AM, gets home about 5 pm. In the winter she is using about 30 kWh/day.
- She uses the climate control from the App to warm the car up before leaving for work in the winter so. Better for the car, better for her.

 

[Jeffs231Leafp]

Yup. And it's worse than that -- if the EVSE is plugged into the car, it slowly drains the 12V battery unless you're actually charging. That vampiric drain on the 12V battery is why I never use the charging timer feature and always pull the EVSE out of my car as soon as it finishes charging. I also like to blip the windshield wipers a few times before I power off the car after arriving home, as that triggers the DC-DC converter to top-up the 12V battery from the traction battery for a minute or two after each wiper blip.

Of course, I'm using a 2013 Leaf. I have no idea if they fixed any of this stuff in a 2024 Leaf.

No drain on battery when plugged in that I know of for Gen2. At least it is low enough that it never affected the Gen2 leaf’s I have owned ( 2018 SL, 2019 SL plus, 2023 SV Plus, 2024 SV Plus ).

 

[Bombastinator2]

Is it rechargeable still? The 12v is lead/acid. A lot of people who replace them do it with LiFePO4 batteries partly because they have a higher voltage.

 

[RYoungberg]

On my 2024 Nissan Leaf; While I was putting in my sunscreen ( black side out for snow/ ice ) I accidentally hit the emergency flashers. I did not notice that they were on. It was about 5 PM, my car was plugged in, on a timer for midnight charging. It was about 20 F at the time and about 16 F overnight. Next morning the car was dead. Got in with the driver side door key. So what I learned is that the 12 VDC battery does not charge when plugged in , unless you are actually able to charge. A quick jump from a sump pump battery backup battery in my garage and it started. Then pressing the timer override, It was then able to charge both the 12 V and the HV battery. But I am not sure if the timer was reset, due to the dead 12 V battery. BTW; The way I discovered it EV Connect was not giving me a charge status.

 

[RYoungberg]

I left my emergency blinker on as a warning to others when I was parked temporarily in a bad spot, drained the 12V in less than an hour. Used jumper cables from another vehicle for about 15 seconds to get the 12V battery up again and the connection to the main battery reestablished. No problems.
As recommended in other posts, if your 12V is older, more than 3 years, best to carry jumper cables or a 'jump battery' pack. Either one are as low as $20. Cheers!