Battery & Cabin Preconditioning Departure Time

I am still seeing different advice regarding the departure time that needs to be set.

This is unfortunately still a very murky concept.

If i were to leave work at 5pm every day, with the car plugged in.

What time do I set to have both battery and cabin preconditioned?

2pm (3 hours earlier) or just 5pm?

Thanks.

Set it to 5 p.m. In the time leading up to then, the car will automatically activate the climate system to precondition the HV battery and cabin temperatures so that they reach ~70ºF at 5 p.m. In extreme temperatures (dead of winter), the car could take up to three hours to achieve that optimum HV battery temperature.

So preconditioning adjusts its start time based upon the car status and temperature?

What happens at the departure time? Does the car maintain the status for 5 minutes or longer or just shut off? Typically my departure time varies by 5-15 minutes. So understanding the sustained window is an open question.

Also, is there any advantage to setting a departure time when the car is not connected to a charger?

Bob Wilson

Setting a departure time primarily conditions the batteries. You have an option to also condition the cabin. The car will keep going with what you told it for about 30-minutes after the set departure time, then shut itself off. Battery warming can take up to 3.5-hours if things are really frigid. Cabin preconditioning typically only starts about 30-minutes before your set departure time, and if you use the preconditioning from the app, or tell the car to keep it on when you stop, that will run for about 30-minutes.

So, set it for when you plan to depart, and you have about 30-minutes of play after that time while it will continue.

and battery precon only works with L2 not L1 charging

good info here http://bmwi3.blogspot.com/search?updated-max=2015-04-24T02:30:00-04:00&max-results=7&start=26&by-date=false

justanotherdrunk said:

and battery precon only works with L2 not L1 charging
. . .

Click to expand...

Interesting, I didn't see that limitation in the Owner's Manual but it does make sense in some cases.

If dealing with sub-freezing temperatures, a Level 1, 1.5kW charger would be stressed. If using the 1.2kW charger that comes with the i3, it would be challenged.

Bob Wilson

I have seen my EVSE peak at 20A during a preconditioning cycle...way more than the level 1 devices can provide, so I don't' think it will even try. It can always condition the cabin, and will do that from the batteries, augmented by the EVSE, if it is attached and the battery level gets low enough to overcome the hysteresis, trip in level.

Q. When Preconditioning via the iRemote app Remote Control menu is activated, only the cabin is preconditioned, not the battery, correct?
A. When triggering Preconditioning from the Remote Control menu, the answer is Yes, only the cabin.

Q. If you want to precondition the battery from the app, you need to set the departure time and then enable “preconditioning for departure," correct?
A. Yes, provided the departure time programmed is at least 3 hours from the time when it is selected.
*Important: This is a very important fact that most i3 owners are not aware of. If you don't set the departure time at least three hours in advance the car is not performing battery preconditioning at all, only the cabin will be preconditioned.

Q. Can you precondition the battery without the vehicle being plugged in?
A. The HV battery, no. The cabin, yes.

Q. Can you precondition the battery while the vehicle is plugged into a 120v source or does it need to be connected to a 240v source?
A. 120V (Level 1/OUC) or 240V (Level 2) have the same effect in terms of Preconditioning. However, if charging on Level 1, the preconditioning consumption is higher than the charge rate, therefore potentially the vehicle will not be fully charged at the departure time.

Q. How early before the departure time will the vehicle begin to precondition?
A. When using the vehicle preconditioning menu, it will depend on temperature, but generally 30-40 minutes prior to the set departure time the cabin preconditioning will start, and the battery preconditioning will start 150 minutes prior to that.

Q. Will the car ever turn a battery warming on by itself if the battery temperature gets critically low. For example, the car is parked outside and plugged in and the battery temperature drops below 30 degrees, will the preconditioning turn on and warm the battery up without owner intervention?
A. No. User intervention is required for battery preconditioning. If the battery temperature is very low, it will be outside its normal operating temperature. As a result, the power output and usable energy of the battery will be reduced.

Q. How about if it gets critically hot – over 105 degrees?
A. If the battery temperature is higher than the optimal operating range and preconditioning is activated, the battery can be cooled. This is not very common due to the fact that the battery is such a high thermal mass, is located close to the ground, and is not exposed to direct sunlight.

Q. Why is it that sometimes after preconditioning (plugged in) the car is left at 97% or 98% SOC? Why doesn’t it fully recharge the car to 100%?
A. When preconditioning using a Level 1 charger, the car will always be below 100%. It could be about 80% or lower.(Because it uses more energy than the 120v source can provide) When using a Level 2 charger, the SOC could be slightly under 100% as the vehicle electrical load stays somewhat constant while the charger will switch off and on.

Q. Will battery cooling occur automatically while you are driving when the battery temp exceeds a certain set point?
A. Yes.

Q. When battery preconditioning is being performed, what is the battery temperature that the vehicle is attempting to achieve?
A. The battery is warmed or cooled to bring it close to or within the optimal operating range of 25-40C (77-104F)

THANK YOU! This is exactly what I needed.

I will set preconditioning Mon-Friday, 5:30 AM. With my current Level 1 charger, 12A using the provided EVSE, it should work perfectly fine for the rest of the summer and well into the fall.

I've gotten notice that my Level 2 charger has shipped and I have a 40A circuit that can power it. So within a week or so, I should have enough power to handle cold snaps in Alabama. Once the the electrical work is done on the house with with 17 kW Generac, I should be good even if another set of tornadoes wipe out the TVA transmission lines.

The only thing I don't like is having a gap between loss of power and the Generac coming online. But this remains an interesting puzzle to figure out.

Bob Wilson