Posts: 40
Joined: Fri Feb 23, 2018 3:30 pm
Location: SoCal

12v battery and using accessories - how does it recharge?

Fri May 11, 2018 5:12 am

From the Nissan Leaf forum, I had learned that the big traction battery recharges the 12v battery that runs all the electronic interfaces. However, it doesn't charge the 12v battery if the car is plugged in. The result is that if someone leaves the car plugged in while they go on a 2 week long trip, when they get back, the 12v battery is dead and the car has to be towed because the electronics won't work to start the car.

I want to install a dash cam that I would like to have run continuously even when the ignition is off. I want to make sure it doesn't drain the battery and I get stuck because the 12v battery is dead even though the traction battery is full. For the Leaf, this would not be a problem IIUC per the above as the traction battery would simply charge the 12v battery as needed and there is no way a dashcam is going to drain that in any short period of time.

Does anyone know how/when the 12v battery in the PHEV Clarity is recharged? Is it from the 17 kwh traction battery? Or does it have an alternator that recharges when the car is running hybrid? Does it only recharge when the car is on? Or will it keep the 12v battery topped off as my dash cam drains it while it sits while I'm out of town for a week? Does it shut down the 12v recharge when plugged in like the Leaf does?

Posts: 17
Joined: Mon Mar 26, 2018 5:22 pm
Location: Arcadia, CA USA

Re: 12v battery and using accessories - how does it recharge?

Fri May 11, 2018 10:36 am

Our prior car was a '13 Ford C-MAX Energi. Plugged in would help keep the 12 V battery charged, opposite of your concern. I have not read much about the LEAF, but that's not a wise design, in my humble opinion. Hopefully Honda didn't do the same as Nissan...

I'm not sure how exactly the 12 V battery is charged, but my suspicion is a DC-DC converter...

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