disconnect battery while away 3 months?

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New member
Nov 8, 2023
New Leaf owner (2019 SL), and wondering best practices for long term holiday. Car will sit idle in driveway for 3 months. Am I right in thinking that there is a small 12 V battery that is specifically for the starter? And that perhaps I can either disconnect or put a small solar panel outside to keep it charged? Any advice welcome. THANKS.
You have an full-battery EV, so it does not have a starter or engine. The 12V battery mainly provides powers for electric devices (e.g., lights, radio, etc.) when the car is OFF, similar to a regular ICE vehicle, and for controls / electronics. This 12V battery gets charged by the main (big) battery when the EV is ON or driven around.

You can find info on EV storage in past posts:

One option would be to remove the 12v battery and put it in your garage on a trickle charger/battery tender during your absence. Or do the same with the 12v still in the car with an appropriately sized extension cord and plugs for outdoor use.
My recommendation:
1. Charge traction battery fully.
2. Drive car a bit to discharge the traction battery to between 80% and 85% SOC.
3. Park car in driveway making sure all accessories are turned off and windows are fully closed. Do NOT plug EVSE into charging port.
4. Unplug anything such as Bluetooth adapters or insurance company monitors from the OBDII diagnostic port.
5. Fully close and lock all doors.
6. Store key fobs far enough from car to avoid radio transmission between fobs and car.

If you follow the above steps, then the traction battery will charge the 12V battery for 5 minutes every 24 hours. This takes very little energy so the traction battery should still be well above 50% SOC when you return. My 2019 SL Plus has been parked at my office for extended periods of time on numerous occasions while I travel on business. There was very little reduction in traction battery SOC% after it was parked for a full month during one of my longer trips. Note that the telematics system goes into deep sleep after 2 weeks so don't be surprised and don't worry when you can no longer check vehicle status through the Nissan Connect EV app on your phone.

Edited to add: The 2019 SL Plus charges the 12V battery for 5 minutes every 24 hours while the 2011 SL only charged the 12V battery for 5 minutes every 5 days. I never completely documented the charging algorithm of the 2105 SL while parked, but all 3 of my LEAF's kept their 12V batteries charged while parked for extended time unless something was left plugged into the OBDII diagnostic port. I never disconnected the 12V batteries while parked and never connected an external 12V charger to my LEAF's.
The car will charge the 12 volt battery every 24 hours, my car sat on the dealers lot for 1 year. 12 volt battery is still original.

Just charge the traction battery to 60% and leave it alone....JMHO