Theoretical: What happens if you fully deplete the battery at home?

[GMan]

Let's say the Air is in your garage, next to your L2 charger, and the HV battery fully depletes. What would be involved to get the car to a state where it could begin taking a charge from the home charger?

Does the 12 volt battery power the charging port door so that it could open? If so, would the vehicle require some minimal amount of charge in the HV battery in order to begin charging from the wall charger?

Or, would the car need to be towed to a Service Center to get it back online?

 

[segbrk]

The charge port door (and access in general) is powered by the 12V. There are instructions in the manual for both manually opening the charge port door and jumping the 12V externally - leads are buried up in the rear right wheel well. I would guess you need 12V power in order for the car to initiate charging as well.

 

[borski]

Let's say the Air is in your garage, next to your L2 charger, and the HV battery fully depletes. What would be involved to get the car to a state where it could begin taking a charge from the home charger?

Does the 12 volt battery power the charging port door so that it could open? If so, would the vehicle require some minimal amount of charge in the HV battery in order to begin charging from the wall charger?

Or, would the car need to be towed to a Service Center to get it back online?

From the manual:

 

[borski]

The charge port door (and access in general) is powered by the 12V. There are instructions in the manual for both manually opening the charge port door and jumping the 12V externally - leads are buried up in the rear right wheel well. I would guess you need 12V power in order for the car to initiate charging as well.

You don’t need to charge up the 12v first.

 

[GMan]

You don’t need to charge up the 12v first.

Thanks @borski - so would I be able to plug in my L2 charger and start charging from zero SOC?

 

[borski]

Thanks @borski - so would I be able to plug in my L2 charger and start charging from zero SOC?

That's my read of the manual, but I've never tried it myself.

 

[knewman]

Step 1 made me wonder, how would I get this door open if the 12v was dead? Turns out you've got to jump the 12v door circuit via leads in the rear right wheel well, underneath the liner. Hope I never need to know that.

 

[Tâm]

Thanks @borski - so would I be able to plug in my L2 charger and start charging from zero SOC?

The BMS (Battery Management System) needs 12V to work. To charge your car, you need to power the BMS.

Yes, you can manually open the charge port and plug in the cord but if your 12V is depleted (because the 900V is too depleted to keep the 12V to be fully charged) then the BMS is not powered.

If that is the case, you need to charge up the 12V first. There's a procedure to do that and you can access the 12V charging leads from the right rear wheel.

If that's too much for you, of course you can call Lucid to either do a mobile service or to tow your car.

 

[Tâm]

Step 1 made me wonder, how would I get this door open if the 12v was dead? Turns out you've got to jump the 12v door circuit via leads in the rear right wheel well, underneath the liner. Hope I never need to know that.

Some people have a habit of keeping their windows down even when the 12V is dead. In that case, just reach through the window and manually open the driver's door from the inside. It works as mechanical leverage system to unlatch the door if there's no 12V.

 

[GMan]

This is very helpful information. To be clear, my car is fine.

I live in a climate where the garage gets hot over the summer. It has reached 109 while the outdoor temp is 120. While away from your car for any extended period, the guidance is to leave your car plugged in. That way if the BMS needs to cool the battery, the car will stay charged.

However, the BMS plus the charging will actually generate heat, which could lead to a situation where the BMS never turns off and the garage continues to heat. I'm not sure how much heat will be generated in this situation if left unattended for days or weeks at a time. The HV battery should not stay in heat over 115 for any length of time.

As such, in my situation, I may choose to instead not leave the car plugged in. Worse case, the HV battery eventually runs out due to the BMS use. However, the confined heat on the garage will not be a runaway train, and may actually minimize any damage to the battery.

 

[Tâm]

This is very helpful information. To be clear, my car is fine.

I live in a climate where the garage gets hot over the summer. It has reached 109 while the outdoor temp is 120. While away from your car for any extended period, the guidance is to leave your car plugged in. That way if the BMS needs to cool the battery, the car will stay charged.

However, the BMS plus the charging will actually generate heat, which could lead to a situation where the BMS never turns off and the garage continues to heat. I'm not sure how much heat will be generated in this situation if left unattended for days or weeks at a time. The HV battery should not stay in heat over 115 for any length of time.

As such, in my situation, I may choose to instead not leave the car plugged in. Worse case, the HV battery eventually runs out due to the BMS use. However, the confined heat on the garage will not be a runaway train, and may actually minimize any damage to the battery.

Good rationale but I still do what the manual says: plug in when not driving.

As long as the 12V is still alive, the BMS works whether you plug in or not.

One of its jobs is to thermo-regulate the main battery whether you plug in or not.

In your case, when your garage is too hot for the main battery, the BMS would automatically turns on the HVAC to cool the battery down to prevent damage whether you plug in or not.

When they BMS turns the HVAC on, your garage would become hotter but your battery would become cooler.

Thus, no matter how much your car causes your garage to heat up, your battery is still nice and cool whether you plug in or not. In the case of not, once the battery is depleted, the battery is no longer protected by the auto thermo regulation anymore.