Model 3 using battery for precon when plugged in

[Foxsbiscuits]

Apologies if this has been posted already, I couldn't find anything similar.

I have my car set to 5pm scheduled charging (via car software) and plugged into a gen 3 connector.
In the morning I turn on the climate and it does not draw from the mains, it uses the battery.

Is this how it's supposed to function? I ask because the manual says it will always draw from mains if plugged in.
However this is the behaviour I'd expect from setting a scheduled charge.
My mains supply is 7kw so I suppose on a very cold day it might be drawing from both supply and battery? The stats app tells me to plug in for precon though.
Just wanted to check if all is ok or if something funky was happening.

Thanks.

 

[Rocky_H]

In the morning I turn on the climate and it does not draw from the mains, it uses the battery.

What are you seeing that tells you it is NOT drawing from mains power?

My mains supply is 7kw so I suppose on a very cold day it might be drawing from both supply and battery?

So now you're saying it might be drawing from mains power? Which is it?

The information I can give is that I think you are correct in your second statement. While it is plugged in, it is supposed to draw from mains power for those large heating draws, such as warming up the battery, or warming up the interior cabin. And yes, if both of those are running at the same time, for a lot of people, it is more power consumption than their wall connection can provide. So it may need to consume 9 kW of power to run both (made-up number), and it can only draw 7 kW from your plug, then it will start running down the battery too, with that extra 2 kW of power needed.

 

[Foxsbiscuits]

What are you seeing that tells you it is NOT drawing from mains power?

Car used 1.2% of battery to precondition climate, and a tip to plug in next time. Although I suppose it could have also been drawing from the mains and the tip was generic/inaccurate.

So now you're saying it might be drawing from mains power? Which is it?

I don't know when it's drawing from the mains, all I have is car battery state and the wall connector log which doesn't log direct powering, only charges.

So it seems it will still draw from supply even if charging is scheduled for another time. I guess it doesn't class it as charging...

 

[Rocky_H]

So it seems it will still draw from supply even if charging is scheduled for another time. I guess it doesn't class it as charging...

Yes, it has always been that way. You can have a scheduled charging start time, like 1:00 AM (I do too). But that is for when it will run the actual full charging event. That has never applied to if you tell the car to turn on the heat, or if you open the car door, and that wakes it up, and the heater is on. Those will still draw from the wall unrelated to having a scheduled charging time.

 

[MP3Mike]

My mains supply is 7kw so I suppose on a very cold day it might be drawing from both supply and battery?

Yep, it was likely using more than 7kW to precondition so it used both the battery and EVSE.

The stats app tells me to plug in for precon though.

I think it will say that when your EVSE can't provide enough power to cover all of the preconditioning. (I know it does for me, but I currently only have ~4kW available, so it always draws from the EVSE and the battery when preconditioning.)