Practically the worst way to found out what a company has done is to look at it's patents.
That aside, NO. Take apart your car if you have to convince yourself that it's not implemented.
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Winter charge failure: don't use scheduled charge when very cold.
- Thread starter Ollie Jones
- Start date
Practically the worst way to found out what a company has done is to look at it's patents.
That aside, NO. Take apart your car if you have to convince yourself that it's not implemented.
It used to be possible to get this display on the touchscreen, if you knew a password:
As you can see, it's possible for the battery and drive train loop to be put in series or in parallel operation. There's also an optional linkage from the battery loop to the HVAC loop through the "Chiller", which I assume to be a heat exchanger. Presumably that is intended to allow the HVAC to cool the battery pack. But it could also be used in the opposite direction.
And yes, you should never turn Range mode on while plugged in. It will dial back the power on the pack heater and cabin heater, even though you have lots of power available. Basically, don't ever turn Range mode on except in one extreme situation: the car has completely cold soaked at extreme temperatures, and not plugged in so you can't preheat from AC power. In that case if you need to do a long trip it will help. Otherwise its downsides are much greater than its upsides.
As you can see, it's possible for the battery and drive train loop to be put in series or in parallel operation. There's also an optional linkage from the battery loop to the HVAC loop through the "Chiller", which I assume to be a heat exchanger. Presumably that is intended to allow the HVAC to cool the battery pack. But it could also be used in the opposite direction.
And yes, you should never turn Range mode on while plugged in. It will dial back the power on the pack heater and cabin heater, even though you have lots of power available. Basically, don't ever turn Range mode on except in one extreme situation: the car has completely cold soaked at extreme temperatures, and not plugged in so you can't preheat from AC power. In that case if you need to do a long trip it will help. Otherwise its downsides are much greater than its upsides.
Thanks for posting the image,.
The cabin and battery chiller both tap off the same high pressure feed from the compressor. Vehicle only has A/C, not a heat pump/ reversible set up, so the heat exchanger only works in the cooling mode.
That is true, except we are looking at the “water” loops, not the freon loop. The heat exchanger would inherently work in either direction.
Isn't the blue loop freon? Chiller is refrigerant to coolant heat exchanger. EVAP is cabin evaporator for AC.
The chiller is the air conditioning compressor and the blue loop is refrigerant. EAC is the electronic expansion valve and you can see the refrigerant pressures and temperatures displayed on either side of it (high and low sides). In this particular example, the chiller is not running, so the refrigerant system is at rest.
The green and red loops are coolant, with green being battery and the DC-to-DC converter and red being motor, inverter and charger.
The green and red loops can be combined (run in series mode) when the system wants to scavenge heat from the motor and send it to the battery. The blue and green loops can be combined when the system needs to actively cool the battery with the air conditioning compressor (more accurately referred to as the chiller in this context).
I do not see a way for the red loop to be combined with the HVAC, as there is no coolant heat exchanger present in the HVAC system. There is no way to dump heat into the refrigerant loop and have it heat the cabin, thus making it impossible to use excess motor/drivetrain heat to heat the cabin air.
The green and red loops are coolant, with green being battery and the DC-to-DC converter and red being motor, inverter and charger.
The green and red loops can be combined (run in series mode) when the system wants to scavenge heat from the motor and send it to the battery. The blue and green loops can be combined when the system needs to actively cool the battery with the air conditioning compressor (more accurately referred to as the chiller in this context).
I do not see a way for the red loop to be combined with the HVAC, as there is no coolant heat exchanger present in the HVAC system. There is no way to dump heat into the refrigerant loop and have it heat the cabin, thus making it impossible to use excess motor/drivetrain heat to heat the cabin air.
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NeverFollow
Active Member
I found this to be an interesting idea, like putting an extra blanket to keep the battery warm,
mostly by limiting heat flow convection with the outside surrounding ambient air under the car.
However I think that you need to consider the thermal conduction of the battery aluminium frame.
Unless you manage to isolate thermally the battery itself from the rest of the body frame,
there will be a lot of heat transfer between the battery frame and the whole body of the car,
which will be itself at the same temperature than the ambient temperature.
Which metals conduct heat best: Common metals ranked by thermal conductivity
Rank - Metal - Thermal Conductivity [BTU/(hr·ft⋅°F)]
1 ....... Copper .......... 223
2 ....... Aluminum .......118
3 ....... Brass .............. 64
4 ....... Steel ............... 17
5 ....... Bronze ............ 15
Thermal conductivity is the property of a material to conduct heat.
Materials of high thermal conductivity are widely used in heat sink applications
and materials of low thermal conductivity are used as thermal insulation.
The reciprocal of thermal conductivity is called thermal resistivity.
I sometimes do short trips in freezing temperatures.
I am happy with the performance of the cabin heater while range mode is turned on, and with the limited regen available from my cold-soaked battery.
If I turn range mode off, an offensive amount of power is wasted on heating up the battery, only to let it cool down completely before I next use the vehicle.
What are the other downsides of range mode?
The big problem with Range mode is that it limits pack and cabin preheat while plugged in, which is very counterproductive. It’s a buried feature so it is easy to forget.
mknox
Well-Known Member
On my home sub-meter, the power spike is instantaneous when I turn on HVAC remotely. Now that is power to the battery pack not directly to the HVAC heater which is supplied via the pack.
Looking at my iPhone app which refreshes every second or two, my cabin temp will rise at 1 degree F every time the app refreshes (i.e. every 1-2 seconds) no matter how cold and no matter where it starts from (I've watched it go up from -20 F) and right from the get-go.
All HV components (pack charger, power pack, heaters, 12 V charger, and AC compressor) on the S&X share the same HV circuit. There is not a separate in and out on the pack. If the pack is charging (net power to the pack), all accessory loads are being supplied by the charger. If you were on a 15A 120V circuit and ran all the heaters (so load > 1,440W - inefficiency), both the charger and the pack would be supplying power to the accessories.
mknox
Well-Known Member
True. I wonder why Tesla just doesn't temporarily turn Range Mode off when plugged in and pre-heating / charging? They do something similar with the HVAC: I usually keep it out of Auto and customize some of the settings. When I remotely enable, it flips to full Auto then back to my custom settings when I get back into the car.
I'm not sure that's correct. Tesla can meter power into the pack and out of the pack separately (you can get these values from some of the diagnostic tools) so something is going on there.
I have found that sometimes when I run remote HVAC for a period of time, my battery SOC will actually go up a percent or two. Not recovering "cold" range as it warms up, because it does the same in the summer when I run the a/c remotely. It seems to me like it's metering the power draw from the main pack, then throttles the on-board charger to match this demand (approximately).
That is interesting, I wonder if it is done to compensate for charging/ discharging loss (only part of power in goes to SOC, only part of SOC goes to output power). The pack only has two HV terminals, so there can only be one current path.
Is the vehicle below the Charge To SOC when you do this? It doesn't keep the pack exactly at that point, so if it has drifted down and the car is awoken, it may also trigger a new charge cycle. Or the granularity of charge rate is not so great, so it errs to the side of battery charging.
I don't believe you. Are you saying only my car got a defective heater, and everyone else's car works fine? I've been hearing that kind of stuff on this forum for years about all kinds of things. Just a state of complete denial.
Prove your assertion with logs. Also use Powertools app to stream data at a high rate (~200ms sample rate, if I recall).
ThosEM
Space Weatherman
Your ungrammatical dismissal fails to explain my observations. Some of us use observables to avoid taking the car apart. And most of the time, we refrain from snippiness when someone cites observations to cast doubt on our arguments.
“The first principle is that you must not fool yourself and you are the easiest person to fool.”
―Richard Feynman
mknox
Well-Known Member
No. I can, for example, set the slider and charge to 80%, then later, with the car still at 80% activate the remote HVAC for a while. When I come out, the car may be at 81 or 82%. Doesn't happen all the time (usually with longer pre-heating/cooling sessions) but happens summer or winter.
I have no idea how other people's cars work in this regard, nor am I trying to "deny" anything. I just know what I see with my own car, a sample of 1. I am not using any kind of logs (other than my sub-meter on the car's charging circuit). I can activate the remote heat and watch the temperature immediately start to rise by about 1 degree F every time the Tesla app refreshes, which seems to be about a second or two.
EDIT: The following occurred to me: My car is an older version that does not have the cabin temperature sensor/aspirator in the center console. The temperature sensor on my car is located behind/below the dash in the area of the steering column. It is possible that it is more rapidly sensing the heat from the floor vents in that area than it would trying to measure temperature in the center of the cabin.
ThosEM
Space Weatherman
Those who doubt that drive train heat gets routed to the battery and cabin may want to take a look at this thread: Interesting finding about Range Mode
I don't think the cabin has a glycol radiator, only PTC heater and AC evaporator. Is there a specific post out of the 14 pages that says otherwise?
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