Help! Air Conditioning problems - Road Trip in Progress!

[Ingineer]

That would be ideal, and in fact it was originally speculated that this is how they were going to implement it.

One thing they do is utilize the coolant loop through the battery, motor and inverter to extract heat in the winter. A resistance heater supplements this. I have found on long winter road trips, my consumption is barely off summer levels. It spikes at first, but tapers off as this closed loop gets warmed up by everything running. On short trips, when the car has had a chance to cold-soak, my consumption is off the charts (literally, it goes beyond the scale of the energy graph).

Well, there isn't any possibility of waste heat from the powertrain being used to heat the cabin, there is no glycol loop inside the cabin, only the PTC electric resistance heater (I think it's about 6-7kW). The waste heat can be used to warm the battery however. I suspect the large pull is the either the cabin heater warming up or the battery heater doing the same. After either is up to temp, it needs less to maintain.

 

[mknox]

Well, there isn't any possibility of waste heat from the powertrain being used to heat the cabin, there is no glycol loop inside the cabin, only the PTC electric resistance heater (I think it's about 6-7kW). The waste heat can be used to warm the battery however. I suspect the large pull is the either the cabin heater warming up or the battery heater doing the same. After either is up to temp, it needs less to maintain.

I believe the coolant loop does flow through the HVAC system to allow excess heat to be used in the cabin. See early energy display and diagnostics screens below:

 

[Cyclone]

How do we get to those screens? My Engineer mind is jumping up and down in excitement!

 

[Ingineer]

I believe the coolant loop does flow through the HVAC system to allow excess heat to be used in the cabin. See early energy display and diagnostics screens below:

No, Unfortunately it doesn't. See the box in the second image you posted labelled "HVAC". That's the cabin part. There is an Evaporator (Cooling for A/C) and a PTC heater. There is no Glycol loop in the cabin. The only way you could get heat from the powertrain into the cabin is to install a reversing valve and convert the Evaporator into a Condenser, and the hardware to do that doesn't (yet) exist.

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How do we get to those screens? My Engineer mind is jumping up and down in excitement!

The only way to get into the Diagnostic screens shown is to get a code from Tesla, and they will not give you one. If you feel adventurous, hold down the "T" at the top until it flashes then let go and you'll get the prompt for the access code. IIRC, the code is at least 6 digits and it automatically changes often, and is different for each car. If you do manage to figure it out, it would only work for a short time. These screens are also enabled anytime Tesla accesses the system from their laptops.

 

[Cyclone]

The only way to get into the Diagnostic screens shown is to get a code from Tesla, and they will not give you one. If you feel adventurous, hold down the "T" at the top until it flashes then let go and you'll get the prompt for the access code. IIRC, the code is at least 6 digits and it automatically changes often, and is different for each car. If you do manage to figure it out, it would only work for a short time. These screens are also enabled anytime Tesla accesses the system from their laptops.

I figured as much foas the diagnostic screen (I heard about the rotating codes on the "T" before), though I was hoping to see the Power tab on Energy app was available and I just missed enabling it. I really would like to see the power draw of the HVAC in my car.

 

[Ingineer]

I figured as much foas the diagnostic screen (I heard about the rotating codes on the "T" before), though I was hoping to see the Power tab on Energy app was available and I just missed enabling it. I really would like to see the power draw of the HVAC in my car.

If you want to see the power draw of the HVAC, simply connect your charger but have it set to NOT charge then fire up the HVAC. If it's drawing any appreciable amount the charger will call for shore power and you'll see the amps come off zero. Multiply the Amps x the volts shown and you roughly have your HVAC load in watts. Likewise for any large loads.

 

[mknox]

If you want to see the power draw of the HVAC, simply connect your charger but have it set to NOT charge then fire up the HVAC. If it's drawing any appreciable amount the charger will call for shore power and you'll see the amps come off zero. Multiply the Amps x the volts shown and you roughly have your HVAC load in watts. Likewise for any large loads.

You can also see a good approximation of it just by sitting in the car stopped with the HVAC on. The power display will show up to about 10 kW of heating power in the winter when the car is first turned on and is cold soaked. Turn the system off and the power meter will drop to near zero.

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No, Unfortunately it doesn't. See the box in the second image you posted labelled "HVAC". That's the cabin part. There is an Evaporator (Cooling for A/C) and a PTC heater. There is no Glycol loop in the cabin. The only way you could get heat from the powertrain into the cabin is to install a reversing valve and convert the Evaporator into a Condenser, and the hardware to do that doesn't (yet) exist.

I realize the car doesn't have a reverse cycle a/c, or heat pump, but I thought the coolant loop did feed a small "heater core" to transfer some of the heat into the cabin in the winter. A Tesla representative once told me that in the summer, the excess heat is expelled through an external radiator at the front, but in the winter, the coolant by-passes the radiator and feeds this "heater core". Here's what I have observed in very cold temperatures (around 0 F): The car will initially pull about 10 kW of power just to heat the cabin and the battery. After a half hour to hour of driving, this drops to less than 1 or 2 kW. If I stop for, say, 5 minutes I can get back into a very cold cabin and not see this initial high spike of power, even though I am getting heat from the vents in the car . If I drive for 2 or 3 hours in these temperatures, my Wh/mi numbers are very close to what I would see in the summer.Something seems to be going on to substantially reduce the amount of energy it takes to heat my cabin after about an hour or so of driving in extreme cold.

 

[scottm]

The only way to get into the Diagnostic screens shown is to get a code from Tesla, and they will not give you one. If you feel adventurous, hold down the "T" at the top until it flashes then let go and you'll get the prompt for the access code. IIRC, the code is at least 6 digits and it automatically changes often, and is different for each car. If you do manage to figure it out, it would only work for a short time. These screens are also enabled anytime Tesla accesses the system from their laptops.

4 digits got me in for a look-see

It's a 6 hour window, that's where the six comes in!