It could be instant, but it's more like several minutes to get to full power, because of software.
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Winter charge failure: don't use scheduled charge when very cold.
- Thread starter Ollie Jones
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It could be instant, but it's more like several minutes to get to full power, because of software.
mknox
Well-Known Member
Mine seems to be pretty instantaneous, but it probably does try to balance the electrical load between the cabin heater and the battery loop, at least at startup if the battery is very cold.
ThosEM
Space Weatherman
Jeff, this is the position many EV drivers take, but arctic cold is something difficult to deal with and practicality is important, too. Moreover, a car with a combustion heater is a long way from a hybrid with a full ICE drivetrain. Even moreover, it's not strictly necessary to use fossil fuels for combustion. There is carbon neutral biogas increasingly available, as described in this article: Electric-Car Battery Energy: Why Waste It On Cabin Heating? (Video)
ThosEM
Space Weatherman
The system also scavenges heat from the motor and battery, if available, and that part requires the coolant loop to warm up.
There's no balancing. It's just slow. Looking at a log from Saturday, starting at ~20F outside only hit full power in the 4th minute of being on. Frankly if it was instantaneous, I'd always skip preheating. I only preheat enough for the heater to ramp to full power.
Try watching the car with something like Remote S, that's refreshing every 9 seconds by default.
Why in the world would it work like that? Is there some physical limitation to how quickly PTC heaters can safely heat up? (It certainly wouldn't be to conserve power for the battery heater since a few kWs it's such small potatoes compared to the drivetrain power draw.)
I thought this was just a myth. Can someone confirm or refute this?
I don't see any way for this to work based on these heating/cooling system diagrams: Tesla Thermal Management System - explanation
It maybe partly be to limit thermal stress on the element and rest of ductwork. It may also be the time constant of the software filter that adjusts heating power while driving (in which case they might want to add a condition for initial heat up to speed things along).
I would bet any amount of money it's the latter. Stuff that doesn't get used normally in Palo Alto works very poorly. You can guess the whole list without me telling you:
wipers
heated wiper nozzles
battery heater
cabin heater
heated steering wheel
heated seats.
Shall I go on? No need to go into details of how they don't work quite right.
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GM had heated wiper fluid system that burned up. Wife's GM heated seat overheated then failed. Same GM had a broken air door that caused 100% cold air all the time. Same GM rear wiper doesn't even touch the glass. Replaced at least 2 wheel bearings and the transmission on two of our GM cars. GM rear diff AWD solenoid failure. Two GMs with broken door handles. What's your point?
At least if it is SW, Tesla can fix it without needing to take car in.
I wouldn't buy a GM car, ever. My only interaction with them will be at a rental agency.
Assuming it *EVER* gets fixed. At this point, if it does get fixed I don't think I'll own the car anymore at that point.
Only took 4 years to do something this trivial: Elon Musk on Twitter
Really? You consider that a "standard" tankless water heater? That requires a 240V 300A circuit, which is twice the entire electrical supply of my house. Here's from the description of it:
"One of the most powerful electric tankless water heaters available today"
Most of the ones at Home Depot are 3.5kW, 6kW, 11kW, 13kW, 22kW, 24kW, 27kW, and then yes, the huge 36kW one. You basically picked the biggest one they have and called it standard, which is pretty funny.
Yeah the problem with my argument is clearly the water heater I picked made out of unobtanium. *THATS* the problem with my argument.
Well, that you think 36kW is a necessary level of heating for the battery pack is the real problem. But you drew that erroneous conclusion from thinking that is a mid-range power level for a water heater.Yeah the problem with my argument is clearly the water heater I picked made out of unobtanium. *THATS* the problem with my argument.
Uhh, no. If you were keeping up, I said 70kW is the necessary level. This would mean no limited regen, almost always.
mknox
Well-Known Member
Mine definitely does not work like that. The Tesla app will update about every 2 seconds (I also have Remote S) and mine will increase temps at about 1 degree F every 2 seconds. I have watched it do this from temps as low as -20 F. It takes only a couple of minutes for mine to get from well below freezing to 70 F. I do this all the time.
I have a sub-meter on my car's charging circuit and the power will spike right up and only taper after a few minutes when the car has warmed up.
Watch the power consumption, and how long it takes to get to max power. PTC power curve should be the inverse, high instantaneous power, reducing consumption as the core temp rises. Tesla's control algorithm is braindead.
A direct connect PTC acts that way, but the Tesla cabin heater is software controlled for variable power. Non-optimally tuned for this use case might be a more accurate description.
That's what I said.
Yeah that would be the phrase if it worked poorly in 2014, followed by and update that made it work "optimally" in 2015. Now that it's 2018, it's just crap. Not pulling punches for Tesla.
ThosEM
Space Weatherman
The Tesla patent on the system, at least, clearly references a mechanism for scavenging heat from the drive system. Whether they implemented it may be open to question. However, I've noticed that the demand for heat from the battery powered resistance heater drops pretty noticeably as a trip progresses, and I tend to attribute that to this capability.
Patent US20100025006 - Electric vehicle thermal management system
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