Battery warming in cold weather, even when not plugged in?

[tuffcalc]

Noticed something today in cold Ontario.

Went outside to add some air to the tires and I could hear a pump running at the front of my model 3. Presumably the heating/cooling loop for the battery. The car was in sleep mode and my phone was not in my pocket.

I don't have a level 2 charger, so I've been leaving it unplugged overnight (plugging into a 120v seems like a waste as it doesn't add any charge but draws a full 12 amps). Overnight I notice I lose some range to the snowflake symbol, but that range comes back after the battery is heated up. Vampire drain is otherwise is very low. With vampire drain so low, I was surprised to hear a pump running.

My thoughts:

1. In very cold weather Tesla is trying to slightly warm the battery even when in sleep mode;
2. The proximity sensors of the car are starting a pump when someone walks within range; or
3. Gremlins.

Anyone have any idea what the pump is doing and/or at what point it tells itself to come on?

 

[5_+JqckQttqck]

3 - 100%

 

[darkenergy]

Noticed something today in cold Ontario.

Went outside to add some air to the tires and I could hear a pump running at the front of my model 3. Presumably the heating/cooling loop for the battery. The car was in sleep mode and my phone was not in my pocket.
<snip>
Anyone have any idea what the pump is doing and/or at what point it tells itself to come on?

I'm not sure I can reasonably comment on the reason, but I can confirm that I've definitely heard that kind of noise multiple times. We generally leave the car plugged in to a 125v EVSE that is only powered overnight (7pm to 7am).

 

[Lon12]

I hear the pump often. Parked in garage, above zero, not plugged in. Even when it is plugged in the car is not drawing shore power when the pump is running.

 

[chevycc]

I know the battery management system monitors the temp of battery. If it is too cold, it use the battery heating/cooling loop to warm up the battery. I read somewhere that 3 doesn't have a dedicated battery heater like S/X. It uses its motor's residual heat to heat up battery. How the motor generates heat while not running is beyond me. So it's probably the pump of battery temp management loop that you are hearing.

 

[Lon12]

Definitely not heating the battery in my case. Just moving the fluid.

 

[tuffcalc]

Definitely not heating the battery in my case. Just moving the fluid.

Agree with this. Moving fluid but unlikely to be heating anything. If it was heating the battery the battery drain would be massive and very noticable.

 

[Zirak]

One thing I noticed was before I took my car to the SC to fix a charge port issue, they did a BMS update on my car (which was long overdue, since I got my car in May 2018). Before this update my car would never get the "Battery is warming" indicator (but I would get the snowflake), now I get "Battery is warming" indicator every time I start to drive for the day.

 

[yyzbig6]

One thing I noticed was before I took my car to the SC to fix a charge port issue, they did a BMS update on my car (which was long overdue, since I got my car in May 2018). Before this update my car would never get the "Battery is warming" indicator (but I would get the snowflake), now I get "Battery is warming" indicator every time I start to drive for the day.

Interesting... I got my car in May too, and I never ever saw "Battery is warming". But it did throw a "Unable to charge" and "Needs service" notice after a -15C night last week. Now I'm waiting for a full battery replacement from the SC.

 

[Zirak]

Interesting... I got my car in May too, and I never ever saw "Battery is warming". But it did throw a "Unable to charge" and "Needs service" notice after a -15C night last week. Now I'm waiting for a full battery replacement from the SC.

Ouch full battery replacement? It wouldn't charge at all? I'd figure it'd be a software glitch or something and would try to reset the car..

 

[RedM3]

Last time I was in service (for brake clips), they updated my battery firmware. They told me they are proactively updating it as other cars go in.

 

[bijan]

One thing I noticed was before I took my car to the SC to fix a charge port issue, they did a BMS update on my car (which was long overdue, since I got my car in May 2018). Before this update my car would never get the "Battery is warming" indicator (but I would get the snowflake), now I get "Battery is warming" indicator every time I start to drive for the day.

In my experience it has to be around -15C or colder and cold soaked battery to get battery is warming message. I preheated the car the past few days and didn't get it even though it was below -15C. But I got it every day it was cold last weekend,