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Tesla Model 3 in Australia

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#6,844
WoodWombat said:
Recent Nissan Leafs, Audi E-tron, Jaguar IPace, Mercedes EQC to start. I think that even the new Vauxhall eCorsa uses a reverse cycle system. I think that Tesla is one of the few still using resistive heating, but it may be for a very good reason, since Tesla are also one of the most efficient EVs on the market!
Click to expand...

I believe the Jaguar iPace uses a heat pump, so I guess it's poor overall range is caused by some other inefficiency.
 
#6,845
The heating/cooling system in the Model 3 for the cabin, batteries and motors is quite complex.
Read up about the 'superbottle' if you want to learn more, quite interesting.
https://jalopnik.com/the-tesla-model-3s-superbottle-easter-egg-is-a-fascin-1830992728
I haven't read enough to be clear if this affects the cabin though, some reports say it does and some say it doesn't. You'd think though the heat from the motor could be used to heat the cabin at times though.
 
  • Informative
Reactions: davegp
#6,846
I just gave Tesla a poke and got this reply:
"
The delivery team are currently working on thousands of deliveries and there are a lot of moving pieces involved but they will definitely be in touch when your Model 3 is ready.

They will typically reach out with 7 – 10 days’ notice to schedule your delivery date and issue your final invoice.
"
 
#6,851
Vostok said:
Yep, heat pumps are definitely more efficient than resistive heating down to 0°C or just below, but at colder temperatures resistive will be more efficient.
Click to expand...
Hmm, I disagree. A purely resistive heater will have an efficiency of about 1 all the time; a heat pump may have a coefficient of performance of say 5 in moderate temperature gradients, reducing as the temperature delta rises. However, the COP can't ever get lower than 1 in theory, because any energy used by the compressor will still eventually be delivered as heat.

Certainly there's no physical reason why a heat pump can't work below 273K, which is an entirely arbitrary value we just happen to be familiar with; after all, when you make liquid nitrogen or any other cryogenic substance, you're using a heat pump to pump heat out, and you're able to reach very low temperatures.

The theoretical efficiency of a heat pump is related to the temperature difference you're 'pumping against', and the absolute temperature (like Carnot efficiency for heat engines, it's largely equivalent).

A heat pump may become less effective, though, outside of its design temperature range; depending on the working fluid, complications like ice formation (i.e. insulation) on the heat source, and so forth. It may be that the output (and input) goes to near zero when the working fluid no longer evaporates or whatever, but that's not the same as efficiency.

I am kinda disappointed in the way the Tesla manages heat, but I'll just have to accept that the various bits I'd have done differently have indeed been carefully considered and it just wasn't worth doing the way I'd have done. Aside from the lack of ability to heat the cabin with a heat pump, another example is the lack of ability to use waste drive-train heat in the cabin (https://teslamotorsclub.com/tmc/posts/3897624/); I might guess that under conditions where you would want cabin heating, there's no (or very rarely) "spare" drive-train heat available (presumably during Supercharging we don't care about efficiency and are happy to use the resistive heater...).
Anyway... I'm just going to have to get over worrying about every last bit of efficiency, especially in relation to Tesla's notoriously bad vampire drain.
 
#6,852
aegidius said:
Lead-acids like being kept full, so they will have a long and comfortable life, apart from the odd total failure.
Click to expand...
Lead likes to be kept full but from what I understand the 12V battery in Tesla gets constantly full cycled, so it does not just sit full. And from the forum posts even if you do not drive the car, the cameras and electronics cycle the battery couple of times a day. So it gets charged from main battery pack when it falls below set charge, then charged until full and then used until needs charge again. So most of the time it is somewhere between full and empty. Since Lithium can do way more full cycles than Lead based battery, this would work perfectly with Lithium and since Lithium does not want to sit at full or empty they can just set the charge start to say 10% and full charge limit to 90% and the battery will be a happy camper.
 
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#6,855
bay74 said:
Hmm, I disagree. A purely resistive heater will have an efficiency of about 1 all the time; a heat pump may have a coefficient of performance of say 5 in moderate temperature gradients, reducing as the temperature delta rises. However, the COP can't ever get lower than 1 in theory, because any energy used by the compressor will still eventually be delivered as heat.

Certainly there's no physical reason why a heat pump can't work below 273K, which is an entirely arbitrary value we just happen to be familiar with; after all, when you make liquid nitrogen or any other cryogenic substance, you're using a heat pump to pump heat out, and you're able to reach very low temperatures.

The theoretical efficiency of a heat pump is related to the temperature difference you're 'pumping against', and the absolute temperature (like Carnot efficiency for heat engines, it's largely equivalent).

A heat pump may become less effective, though, outside of its design temperature range; depending on the working fluid, complications like ice formation (i.e. insulation) on the heat source, and so forth. It may be that the output (and input) goes to near zero when the working fluid no longer evaporates or whatever, but that's not the same as efficiency.

I am kinda disappointed in the way the Tesla manages heat, but I'll just have to accept that the various bits I'd have done differently have indeed been carefully considered and it just wasn't worth doing the way I'd have done. Aside from the lack of ability to heat the cabin with a heat pump, another example is the lack of ability to use waste drive-train heat in the cabin (https://teslamotorsclub.com/tmc/posts/3897624/); I might guess that under conditions where you would want cabin heating, there's no (or very rarely) "spare" drive-train heat available (presumably during Supercharging we don't care about efficiency and are happy to use the resistive heater...).
Anyway... I'm just going to have to get over worrying about every last bit of efficiency, especially in relation to Tesla's notoriously bad vampire drain.
Click to expand...


I'm interested because I'll likely be out in winter all night in cold conditions and likely car camping etc at a significant distance from charging..
 
  • Like
Reactions: MonicaPlease
#6,856
TMacinAus said:
I just gave Tesla a poke and got this reply:
"
The delivery team are currently working on thousands of deliveries and there are a lot of moving pieces involved but they will definitely be in touch when your Model 3 is ready.

They will typically reach out with 7 – 10 days’ notice to schedule your delivery date and issue your final invoice.
"
Click to expand...
My White P3D+ is ready and being given to someone else apparently, I have received nothing from Tesla since ordering and being a Day 1 Reservation has clearly meant nothing as reservations 2 years later are getting allocated the same car in Sydney o_O
 
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