Pre-Heating/Cooling Does NOT use Shore Power?

[efusco]

Well, the plot thickens.

I took my car out for a drive to drain some of the battery (I know, painful).

Charged it up to the max and used my tablet to remotely preheat the car. Over the period of two minutes or so, I dropped from 241 to 239 rated miles with no indication of charging or using any shore power to facilitate heating. Here's the link to the video. The next test will be to see what happens in the early morning (although I generally need to get going in the morning .

Video

Try it again by triggering the preheating from outside the car with all the doors on the car closed. I think it may behave differently since you were sitting in the driver's seat and the door was open.

 

[kevincwelch]

Try it again by triggering the preheating from outside the car with all the doors on the car closed. I think it may behave differently since you were sitting in the driver's seat and the door was open.

Good point. Will check and report back.

EDIT:

Well, I'll be a monkey's uncle. So, here's what I did. I remotely turned on the heat without opening the door or unlocking it as you suggested.

Sure enough, the UMC started to kick on and the display showed 1 amp of current.

Then I watched it. I watched it preheat the cabin as I watched my range dip from 238 down to 235. So, perhaps it does draw some shore power, but not enough in my opinion to prevent the range from dropping.

 

[montgom626]

My 2012 Volt does not use shore power when preheating or cooling, so I do not expect the MS to use shore power either.

 

[efusco]

My 2012 Volt does not use shore power when preheating or cooling, so I do not expect the MS to use shore power either.

If you base your Model S expectations on your Volt experience...you're in for many very pleasant and unexpected surprises!

 

[montgom626]

If you base your Model S expectations on your Volt experience...you're in for many very pleasant and unexpected surprises!

How true. Now that I have one each (Volt and MS) I am living the dream!!!!

 

[efusco]

Good point. Will check and report back.

EDIT:

Well, I'll be a monkey's uncle. So, here's what I did. I remotely turned on the heat without opening the door or unlocking it as you suggested.

Sure enough, the UMC started to kick on and the display showed 1 amp of current.

Then I watched it. I watched it preheat the cabin as I watched my range dip from 238 down to 235. So, perhaps it does draw some shore power, but not enough in my opinion to prevent the range from dropping.

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Yea, that's exactly what I've seen. I suspect it's a sort of permissive drain, they'd rather a small drain than risk an over charge. I bet there's no integrated feedback that would allow a 1:1 power in to power used balance, they're opting to be conservative.




Evan, Via Tapatalk

 

[montgom626]

Yea, that's exactly what I've seen. I suspect it's a sort of permissive drain, they'd rather a small drain than risk an over charge. I bet there's no integrated feedback that would allow a 1:1 power in to power used balance, they're opting to be conservative.

I don't own a Leaf, but I am going to take a wild guess that the Leaf is the same as the MS and the Volt. None of them use shore power when preheating the cabin. There is an engineering reason for this behavior. I just don't know what it is.

 

[efusco]

I don't own a Leaf, but I am going to take a wild guess that the Leaf is the same as the MS and the Volt. None of them use shore power when preheating the cabin. There is an engineering reason for this behavior. I just don't know what it is.

Have you watched the 2 videos I posted? The MS clearly is using a small amount of shore power when heating/cooling--I've clearly documented that behavior.

 

[montgom626]

Have you watched the 2 videos I posted? The MS clearly is using a small amount of shore power when heating/cooling--I've clearly documented that behavior.

I have and I love the videos. But 1 amp is nothing. No disrespect meant. If it was pulling 15 amps, then I would be on board.

 

[kevincwelch]

I have and I love the videos. But 1 amp is nothing. No disrespect meant. If it was pulling 15 amps, then I would be on board.

Well...

It's clear that it is drawing power. What is supplied by that power is not known at this point.

I agree that 1 amp is a very small amount. It's clear to me that it's not enough to power the heater without suffering a loss of range. Maybe that's just conditioning the battery. Who knows?

But, we do know from Evan's videos and my accounts that the behavior depends on how the heating is triggered (outside car v. inside car, etc.) and that clearly some power is being drawn from the shore.

Sent via Tapatalk.

 

[Doug_G]

I have recorded my Model S using 4.5A @ 202V shore power while preheating. That's about 1 kW, which is quite sufficient to heat the cabin.

 

[efusco]

Well...

It's clear that it is drawing power. What is supplied by that power is not known at this point.

I agree that 1 amp is a very small amount. It's clear to me that it's not enough to power the heater without suffering a loss of range. Maybe that's just conditioning the battery. Who knows?

But, we do know from Evan's videos and my accounts that the behavior depends on how the heating is triggered (outside car v. inside car, etc.) and that clearly some power is being drawn from the shore.

Sent via Tapatalk.

Exactly, while I agree that 1 amp is pretty minimal, I want to recheck this. Today I'll try putting the car on the charger with a delayed charge, but with the battery with a lower rated range...should be around 200 miles rated when I get home from work and picking up kids. I suspect that just as regen is limited when the battery is nearly full, that the shore power draw is also limited when the range is near full and that perhaps the shore draw will be higher when the battery is at a lower state of charge....I'm not sure, but that's what I suspect.

But as Kevin points out, the car is clearly drawing some small amount of power when the remote heating/cooling is triggered and it may be that Tesla is tweaking this functionality to try to optimize it without any untoward side effects and that with future updates we'll see a better balance b/w shore power use and actual energy drain with heating/cooling.

 

[montgom626]

Well...

But, we do know from Evan's videos and my accounts that the behavior depends on how the heating is triggered (outside car v. inside car, etc.) and that clearly some power is being drawn from the shore.

More to learn. I am excited when we can come to some final conclusions!

 

[DocDog]

Wow. I am amazed at the different experiences that everyone is reporting. Here is my experience, FWIW. Background: Had my MS for 4 weeks now (still on ver 4.2). I have had a Volt for about a year. I am using the UPMC on the 50 amp circuit. I have one charger in the MS. I have a TED home electrical monitoring system. Results: My Volt (when connected to L2 charger) draws as much power (about 3.5 kW) as when charging (240V, 15Amps) when pre-heating via the On-Star app. My Model S (when connected to the UPMC) draws nothing (not even Evan's 1 Amp) when pre-heating via the Tesla app (doors closed, nowhere near the car). Odd.

 

[mknox]

My 2012 Volt does not use shore power when preheating or cooling, so I do not expect the MS to use shore power either.

It may have to do with whether it is charging the battery or not. I recorded my company's Volt drawing up to 300 watts periodically after the battery was fully charged. That was during moderate weather, so I'm not sure what it was... maybe fans or some other form of battery management. It would go as low as 2 watts for the majority of the time.

I get that pre-heating/cooling is not going to use shore power (directly) if the battery is charging. If you're already drawing rated amps to charge the battery, you're not going to be able to pull any more current for the HVAC.

 

[efusco]

Wow. I am amazed at the different experiences that everyone is reporting. Here is my experience, FWIW. Background: Had my MS for 4 weeks now (still on ver 4.2). I have had a Volt for about a year. I am using the UPMC on the 50 amp circuit. I have one charger in the MS. I have a TED home electrical monitoring system. Results: My Volt (when connected to L2 charger) draws as much power (about 3.5 kW) as when charging (240V, 15Amps) when pre-heating via the On-Star app. My Model S (when connected to the UPMC) draws nothing (not even Evan's 1 Amp) when pre-heating via the Tesla app (doors closed, nowhere near the car). Odd.

Not odd, that was the same for all of us with v4.2. The change seems to be with 4.3 and you have to trigger the preheat/cool from outside the vehicle with the app with all vehicle doors closed.

 

[mknox]

My Model S (when connected to the UPMC) draws nothing (not even Evan's 1 Amp) when pre-heating via the Tesla app (doors closed, nowhere near the car). Odd.

I also use a TED monitor, and that has been my experience as well.

EDIT: I'm on 4.2, so that may be it!

 

[efusco]

I'm officially putting this to bed. With only 202 miles rated range, on delayed charging, I remotely activated climate control with the app. Again the HPWC kicked immediately on.

This time, however, the car drew a full 79 amps while still showing delayed charge.

I'll shoot another video if there are still skeptics, but I shot a still that should be plenty convincing.

 

[mknox]

I'm officially putting this to bed. With only 202 miles rated range, on delayed charging, I remotely activated climate control with the app. Again the HPWC kicked immediately on.

This time, however, the car drew a full 79 amps while still showing delayed charge.

First of all, thanks for all of your testing and verification work. It seems that your activation of climate control started the battery charging cycle. 79 amps at 240 volts is just about 19 kW. If all that was going to heat, your interior would be a puddle of liquid plastic and leather in no time! I suspect that charging was initiated but heating was still coming from the pack. Same difference, though... you wouldn't be losing range while it heats (and at 79 amps, you should be gaining a lot of range).

It's getting warmer where I live now, and I won't have to do this much longer, but I have been doing the Max/Standard Charge trick on my phone to start the charge cycle and then I flip on the heat. I guess this is a v4.2 thing.

 

[efusco]

First of all, thanks for all of your testing and verification work. It seems that your activation of climate control started the battery charging cycle. 79 amps at 240 volts is just about 19 kW. If all that was going to heat, your interior would be a puddle of liquid plastic and leather in no time! I suspect that charging was initiated but heating was still coming from the pack. Same difference, though... you wouldn't be losing range while it heats (and at 79 amps, you should be gaining a lot of range).

It's getting warmer where I live now, and I won't have to do this much longer, but I have been doing the Max/Standard Charge trick on my phone to start the charge cycle and then I flip on the heat. I guess this is a v4.2 thing.

Well, yes, I'm confident that there is no direct method to use wall power to power climate control. It must go through the pack and I don't think the car has a sound way to match the climate control's energy use directly to the wall draw, so when charge is near full it draws just a little(1 amp), when the pack has more room, it draws more (79 amps). I would like to watch what happens to the power draw as charge approaches full, I expect it begins to taper.


Evan, Via Tapatalk