Benefit of plugging car in before scheduled charging?

[Olle]

I have my car's charging circuit monitored by a dedicated meter. The only time in 2.5 years that I've ever seen power being drawn from that circuit is when the car is charging, if I open a door and the HVAC comes on, or if I've activated the HVAC remotely. Under no other circumstances have I observed power flowing from the wall.

Very interesting! What are your record high and low garage temperatures during this time?

 

[mknox]

Very interesting! What are your record high and low garage temperatures during this time?

Quite a range over 2.5 years. Recently, it's been in the mid to high 90s here and my garage can sometimes get even hotter inside. In the winter, we have had temps as low as -5 F although my garage, while not heated, does tend to stay a little bit warmer. I haven't measured it, but when it's below 0 F outside, it's probably about 10 F in the garage. Again absolutely zero consumption on my sub-meter except when the car is charging or running it's HVAC based on an open door or remote app control.

 

[Olle]

Quite a range over 2.5 years. Recently, it's been in the mid to high 90s here and my garage can sometimes get even hotter inside. In the winter, we have had temps as low as -5 F although my garage, while not heated, does tend to stay a little bit warmer. I haven't measured it, but when it's below 0 F outside, it's probably about 10 F in the garage. Again absolutely zero consumption on my sub-meter except when the car is charging or running it's HVAC based on an open door or remote app control.

Based on your evidence, I would not benefit anything from plugging my car in when I come home in the afternoon, only to unplug it when the lightning starts and then plug it in again at night.
I will just plug it in when I go to bed from now on then.

 

[mknox]

Based on your evidence, I would not benefit anything from plugging my car in when I come home in the afternoon, only to unplug it when the lightning starts and then plug it in again at night.
I will just plug it in when I go to bed from now on then.

Tesla likes to say to keep it plugged in, and for most it's probably good advice. If you're not in the habit, you might end up going away on vacation and forget to plug it in. I've noticed that when I'm away, the vampire drain will cause the charging cycle to come on and "top up" the battery every couple of days. Quite a while ago, it was exactly 2.5 kWh every other day when parked unattended. It seems once the battery drifts down a certain amount below the setpoint, it will come on and top itself up.

But I agree with you. If I have an electrical storm, I will not plug the car in and I will shut the power off to my HPWC too.

 

[Larry Chanin]

Based on your evidence, I would not benefit anything from plugging my car in when I come home in the afternoon, only to unplug it when the lightning starts and then plug it in again at night.
I will just plug it in when I go to bed from now on then.

Battery conditioning only occurs when the battery is outside certain upper and lower temperature limits. It is quite possible that mkox's garage never experienced those limits. I am pretty sure that a garage temperature of 150 would trigger battery conditioning. If you install an air conditioner your car may no longer trigger battery conditioning either.

Regardless, if you haven't already done so, you should read the manual on Battery Care.

Larry

 

[David99]

That's very interesting. I would have thought it draws power when it runs the coolant pump (which it does here and there to keep the temperature even). But I guess it doesn't. I think just for making it a habit it's a good idea to always plug it in. There are many advantages to having the car plugged in all the time to be able to get grid power when you need and it and most of all, start charging when you want. Nothing worse that forgetting to plug in the car and then finding it with an empty batter next day.

 

[S'toon]

Quite a range over 2.5 years. Recently, it's been in the mid to high 90s here and my garage can sometimes get even hotter inside. In the winter, we have had temps as low as -5 F although my garage, while not heated, does tend to stay a little bit warmer. I haven't measured it, but when it's below 0 F outside, it's probably about 10 F in the garage. Again absolutely zero consumption on my sub-meter except when the car is charging or running it's HVAC based on an open door or remote app control.

Gosh darn it! You're going to make me break out a calculator to convert to metric, aren't you?

 

[mknox]

That's very interesting. I would have thought it draws power when it runs the coolant pump (which it does here and there to keep the temperature even). But I guess it doesn't.

You're right. I have heard the cooling pump and even when my car is plugged in, I see no record of power draw on my sub-meter. The car seems to do these little things that gradually draw the battery down, and then at some pre-determined delta from setpoint, a charge cycle initiates bringing the pack back up to the setpoint.

My guess is that if the cooling system ever did have to come on by itself (as in @Larry Chanin's 150 degree garage scenario), you would see some shore power used just like it does if I turn the HVAC on via the mobile app. It's just that in 2.5 years, I've never seen it happen.

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Gosh darn it! You're going to make me break out a calculator to convert to metric, aren't you?

LOL. Yeah, I do tend to think in US/Imperial units, but probably the majority of forum users here do as well. (Not trying to discount Canadian and European members, it's just that I suspect the population here skews heavily to the US).

 

[Larry Chanin]

Battery conditioning only occurs when the battery is outside certain upper and lower temperature limits.

That's very interesting. I would have thought it draws power when it runs the coolant pump (which it does here and there to keep the temperature even). But I guess it doesn't.

Hi David,

No doubt I was over-simplifying. As I understand it a battery prefers the same temperatures that we do, around 72 degrees. Obviously, attempting to maintain that particular temperature would be prohibitively energy intensive. So I assume Tesla uses an acceptable range of temperatures in which to perform battery conditioning. I suppose in addition to taking simple temperature readings throughout the pack there may be other criteria which triggers running the coolant pump.

I think just for making it a habit it's a good idea to always plug it in. There are many advantages to having the car plugged in all the time to be able to get grid power when you need and it and most of all, start charging when you want. Nothing worse that forgetting to plug in the car and then finding it with an empty batter next day.

I share your recommendation. I personally feel that particularly here in Florida, where garage temperatures are elevated, that it makes good sense to plug in when the opportunity presents itself. Yes, Florida has numerous thunder storms. So surge protection make sense and if a person is around to unplug during a storm, that's okay too. Personally I don't bother.

Larry