Thread: EV general discussion

A couple of years ago, when I looked at the Tesla car build website, you could pick between models and also work out a theoretical range. It allowed you to enter outside air temps, whether the aircon/heater was running, headlights on/off, what diameter tyres you ran, etc, and all had an impact on estimated range, some by 10's of km's.

Originally Posted by JDNSW

Or like VW and Citroen (2CV etc) did for fifty years or more. Not just light aircraft. Surely you are old enough to remember them?

Or my dear old deceased S1 with its home made one.
Passengers used to complain about hot knees.
Terry

At 1.916 km (1.191 mi), Conrod Straight is the fastest section of Mount Panorama, with V8 Supercars almost reaching 300 km/h (186.4 mph). The straight is a roller-coaster ride featuring two distinct crests, the second of which was rebuilt in 1987.

I thought this might be interesting. A Tesla roadster specs make it interesting and just a matter of time possibly. No way the battery would last 1000km while racing of course. With the rules requiring 7 pit stops over the 1000km swapping the battery might do it or add a hydrogen Fuel Cell and the range would be in the bag even at speed. Mr Musk might send me a nasty note?

This is the cars base specs! Remove some of the weight and tuning it to a racing beast and I wonder if it would go the distance?

• Acceleration 0-100 km/h
  2.1 sec
• Acceleration 1/4 mile
  8.8 sec
• Top Speed
  Over 400 km/h
• Wheel Torque
  10,000 Nm
• Kilometre Range
  1000 kilometres
  
  

Originally Posted by JDNSW

Or like VW and Citroen (2CV etc) did for fifty years or more. Not just light aircraft. Surely you are old enough to remember them?

"Je suis désolé, mais je ne parle pas (encore) la langue de Prost (Alain)."

Ich spreche kein Deutsch.

But I DID overhaul Bosch dynamo's from VW cars! The foreman used to tell me: "This is the heart of a VW engine". (the fan is on the same drive)

Originally Posted by scarry

The AC system would probably either operate on R134a or the newer refrigerant,1234YF,which some manufacturers now use.

Whether the system operates on heating or cooling,for a large or medium sized vehicle,i presume it will consume quite a lot of battery power,further reducing the vehicles range.

I have no idea Paul, as this crap is too modern for an old fart like me.
From what I have read some of the modern innovation's include cooling coils in the seats, and much better thermal insulation throughout the vehicle amongst them.

As you will know, the common garden variety air con needs a different type of expansion valve set up to be used in reverse cycle, so will need to be designed that way from the start.

All that I was trying to do here was clarify what is a "heat pump" in relation to a car, EV or not. Maybe you or Rick can elaborate on the pressures involved with a Co2 system. Not something that I would want in a car!

Originally Posted by Old Farang

I have no idea Paul, as this crap is too modern for an old fart like me.
From what I have read some of the modern innovation's include cooling coils in the seats, and much better thermal insulation throughout the vehicle amongst them.

As you will know, the common garden variety air con needs a different type of expansion valve set up to be used in reverse cycle, so will need to be designed that way from the start.

All that I was trying to do here was clarify what is a "heat pump" in relation to a car, EV or not. Maybe you or Rick can elaborate on the pressures involved with a Co2 system. Not something that I would want in a car!

Rick knows more than i do about CO2 systems.

High pressures are the issue.

Looking at a PT chart,at 0 degrees c,pressure is 491PSI,at 30 degrees it is 1032 PSI,and that is as high as it goes on this particular chart.

In supermarkets it is part of a cascade system,using R134a.

So i doubt it is suitable for auto air at all.But in this modern world i could be completely wrong

One of the links Mick put up didn't seem to work,but the other didn't elaborate much at all about how the AC systems in EV's,actually work.I presume they will be a Hermetic compresser of some type,using quite a bit of power from the battery in the EV,particularly in a large to medium vehicle,operating in countries like here.But thats a guess as i can't find much info on how they actually are designed or operate.

Here's something about the heat pump in the Nissan Leaf.

Heat-Pump Cabin Heater | NISSAN | TECHNOLOGICAL DEVELOPMENT ACTIVITIES

This is also interesting:

CORDIS | European Commission

Originally Posted by DiscoMick

Here's something about the heat pump in the Nissan Leaf.

Heat-Pump Cabin Heater | NISSAN | TECHNOLOGICAL DEVELOPMENT ACTIVITIES

This is also interesting:

CORDIS | European Commission

That is the same BS as posted previously:

Conventional air-conditioning systems used an electrical heater........

When the heater is in use, the external capacitor...........

Arh, must be that flux capacitor in use again!