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What's the argument against just relying on "cabin overheat protection" to keep the climate in spec? Seems like that would solve a lot of their supply chain lim

by akozak 7y ago

What's the argument against just relying on "cabin overheat protection" to keep the climate in spec? Seems like that would solve a lot of their supply chain limitations at once with relatively minimal battery drain - though it does seem wasteful to spend energy keeping electronics comfy in the sun.

whymsicalburito 7y ago
I would expect to be able to leave my car in a parking lot for a week or two (unplugged) and still be able to drive away when I return. I feel like with overheat protection the battery would be dead by the time I got back.
- toomuchtodo 7y ago
  Overheat protection deactivates when the battery pack reaches 20% state of charge. EVs are a bit of a different model; whenever parking for long periods, I endeavor to find a lot that lets me plug in, even if it's 120V 15A (which is enough to keep the cabin cool and the battery somewhat conditioned, although not enough to charge if both of the previously mentioned activities are occurring). Haven't had an airport or long term parking lot yet I could not find an approved outlet or EV charger for my use, but YMMV. @leggomylibro: To reply to your deleted comment, you asked if the vehicle needed 1800W to keep itself conditioned but not maintain state of charge. It's closer to 1440W, as a 15A 120V circuit is derated to 12A (80%) for continuous duty cycle. Coolant pumps can be power hungry! @akozak: I believe it is Tesla specific. I am unaware of the feature being present on other EVs.
  - akozak 7y ago
    I'm guessing that's Tesla specific? My Bolt doesn't have (afaik) an automatic cabin conditioning feature so I've never thought about it. Presumably Chevy built it with parts on spec to handle heat.
  - deleted 7y ago
    [deleted]
  - closeparen 7y ago
    Can you leave an EV on a public charger for weeks? I thought you needed to give it up for the next person after a few hours.
    - deleted 7y ago
      [deleted]
    - myself248 7y ago
      This is truly the argument for rooftop solar panels. Not because they'd replenish a meaningful amount of range per day, but because they'd provide better-than-ICE unpluggability for stuff like long-term parking, cabin ventilation, battery maintenance, telematics modem sleep current, etc.
- gwern 7y ago
  That, and 'overheat protection' apparently doesn't work...
mannykannot 7y ago
I have a different issue with the "cabin overheat protection": claiming that it is to "protect dogs and children" when, even if working as intended, it could allow a car to reach a temperature dangerous to children, is highly irresponsible -- even if Tesla also said that you should constantly monitor the temperature to ensure that it is safe. There's no justification for this sort of dissembling.
- village-idiot 7y ago
  Not only does it seem to be very unethical, I wouldn’t be surprised to see a wrongful death lawsuit eventually.
- mrob 7y ago
  From the article: >Tesla appeared to mostly fix this problem with its "cabin overheat protection" feature (which it sold as being to protect dogs and children, despite the fact that it held the temperature at +40C which is about the temperature where a child's organs will start shutting down) But as the linked explanation says, +40C is the internal temperature which becomes dangerous. This is not the same as the dangerous air temperature. Humans both produce heat by metabolism, and remove heat by sweating. Danger is a function of temperature, humidity, duration of exposure, hydration, clothing, general health, etc. and although I don't know exactly what is safe for children, I point out that a great many people live in climates where air temperature routinely exceeds 40C for several hours at a time.
- manicdee 7y ago
  Cabin Overheat Protection is separate to Dog Mode. If you want to express outrage about abdication of responsibility at least be talking about the relevant feature. Cabin overheat protection is there to protect things left in the car like electronics, and theoretically requires no user interaction. Dog Mode allows the user to dial up the desired temperature and then walk away. This is the actual dangerous feature, because the belief is that the air conditioner will keep the temperature at the level you want it. This despite a history of at least one police dog dying every month in the USA due to equipment failures, and theirs dog cars have specially modified environmental controls to maintain and monitor the temperature, including opening windows as a last ditch temperature control effort. Even those systems fail sometimes. And here is Tesla setting people up for failure using a single air conditioner that is monitored remotely using an internet connection that is flakier than filo pastry.
miahi 7y ago
That's a hidden price (in charging and range) that you have to pay because Tesla did not use proper screens. And it only works when the charge is >20%, so you have to plan ahead if you want to leave the car in the sun at around that charge. It's probably sold as a feature "you'll find your car comfy when you go back", or even "your children will be fine even if you're a horrible parent" and doesn't say anywhere "disabling this feature may cause the screen we provided to melt in the sun, and we don't provide a replacement, as maybe next we'll have a way to fix it". And I don't think the limitation is supply chain, it's just that they want to keep the costs low for the technical debt.

by akozak 7y ago

whymsicalburito 7y ago

I would expect to be able to leave my car in a parking lot for a week or two (unplugged) and still be able to drive away when I return. I feel like with overheat protection the battery would be dead by the time I got back.

toomuchtodo 7y ago
Overheat protection deactivates when the battery pack reaches 20% state of charge. EVs are a bit of a different model; whenever parking for long periods, I endeavor to find a lot that lets me plug in, even if it's 120V 15A (which is enough to keep the cabin cool and the battery somewhat conditioned, although not enough to charge if both of the previously mentioned activities are occurring). Haven't had an airport or long term parking lot yet I could not find an approved outlet or EV charger for my use, but YMMV. @leggomylibro: To reply to your deleted comment, you asked if the vehicle needed 1800W to keep itself conditioned but not maintain state of charge. It's closer to 1440W, as a 15A 120V circuit is derated to 12A (80%) for continuous duty cycle. Coolant pumps can be power hungry! @akozak: I believe it is Tesla specific. I am unaware of the feature being present on other EVs.
- akozak 7y ago
  I'm guessing that's Tesla specific? My Bolt doesn't have (afaik) an automatic cabin conditioning feature so I've never thought about it. Presumably Chevy built it with parts on spec to handle heat.
- deleted 7y ago
  [deleted]
- closeparen 7y ago
  Can you leave an EV on a public charger for weeks? I thought you needed to give it up for the next person after a few hours.
  - deleted 7y ago
    [deleted]
  - myself248 7y ago
    This is truly the argument for rooftop solar panels. Not because they'd replenish a meaningful amount of range per day, but because they'd provide better-than-ICE unpluggability for stuff like long-term parking, cabin ventilation, battery maintenance, telematics modem sleep current, etc.
gwern 7y ago
That, and 'overheat protection' apparently doesn't work...

mannykannot 7y ago

I have a different issue with the "cabin overheat protection": claiming that it is to "protect dogs and children" when, even if working as intended, it could allow a car to reach a temperature dangerous to children, is highly irresponsible -- even if Tesla also said that you should constantly monitor the temperature to ensure that it is safe. There's no justification for this sort of dissembling.

village-idiot 7y ago
Not only does it seem to be very unethical, I wouldn’t be surprised to see a wrongful death lawsuit eventually.
mrob 7y ago
From the article: >Tesla appeared to mostly fix this problem with its "cabin overheat protection" feature (which it sold as being to protect dogs and children, despite the fact that it held the temperature at +40C which is about the temperature where a child's organs will start shutting down) But as the linked explanation says, +40C is the internal temperature which becomes dangerous. This is not the same as the dangerous air temperature. Humans both produce heat by metabolism, and remove heat by sweating. Danger is a function of temperature, humidity, duration of exposure, hydration, clothing, general health, etc. and although I don't know exactly what is safe for children, I point out that a great many people live in climates where air temperature routinely exceeds 40C for several hours at a time.
manicdee 7y ago
Cabin Overheat Protection is separate to Dog Mode. If you want to express outrage about abdication of responsibility at least be talking about the relevant feature. Cabin overheat protection is there to protect things left in the car like electronics, and theoretically requires no user interaction. Dog Mode allows the user to dial up the desired temperature and then walk away. This is the actual dangerous feature, because the belief is that the air conditioner will keep the temperature at the level you want it. This despite a history of at least one police dog dying every month in the USA due to equipment failures, and theirs dog cars have specially modified environmental controls to maintain and monitor the temperature, including opening windows as a last ditch temperature control effort. Even those systems fail sometimes. And here is Tesla setting people up for failure using a single air conditioner that is monitored remotely using an internet connection that is flakier than filo pastry.

miahi 7y ago

That's a hidden price (in charging and range) that you have to pay because Tesla did not use proper screens. And it only works when the charge is >20%, so you have to plan ahead if you want to leave the car in the sun at around that charge. It's probably sold as a feature "you'll find your car comfy when you go back", or even "your children will be fine even if you're a horrible parent" and doesn't say anywhere "disabling this feature may cause the screen we provided to melt in the sun, and we don't provide a replacement, as maybe next we'll have a way to fix it". And I don't think the limitation is supply chain, it's just that they want to keep the costs low for the technical debt.