Misery loves company, so what happens when the traction battery and the 12 V battery are both discharged?
As electric cars become more and more popular, many users or potential buyers will wonder what exactly happens when the main traction is discharged and at the same time as the 12 V auxiliary battery is discharged or totally dead.
It is not a frequent problem, but it might happen for a variety of reasons (for example, if we left the car for too long not plugged-in).
One such problem arises, the car might not only be completely non-operation, but also it will not start charging or not even open.
Access to the 12 V battery
The first step is to get physical access to the 12 V auxiliary battery.
In the case of Tesla Model 3, the low-state of charge of the 12 V battery means that you can't open the doors, the hood, or the charging port.
The manufacturer envisioned an emergency way to open the hood, through powering an external 12 V voltage to the wires hidden in the front.
For demonstration purposes, FreeWire used its Mobi Gen mobile power source (equipped with 80 kWh battery pack with various outlets), but you can use any 12 V source, even a battery from another car.
Reviving 12 V auxiliary battery
Once we obtain access to the 12 V auxiliary battery, we can recharge it (at least to a certain point to get the car operational again) or replace it.
In this step, FreeWire simply connected the battery to 12 V output, supplied by the Mobi Gen.
Recharging the main traction battery
The last step is to connect the car to an outlet (stationary or mobile) or a charging terminal.