To use or not use A/C in hot weather

[wandle MG4 trophy]

I was surprised to see how much my Trophy likes hot weather. I’ve been up and down motorways a lot recently. I stick to 65-70 with A/C on and am getting 4.2 miles to the kWh. Turning the A/C off does not make any noticeable difference. I even have a slight feeling that using the A/C helps a little.

I never drive at speed with the windows open as the air drag is probably more fuel hungry than using A/C.

 

[dsimpkins]

Mine is also very happy in this weather giving me a GOM of 306 miles after charging up to 100% at work. Had to turn the air con down as it was too cold! Might sleep in the car tonight

 

[fshuk1]

I have also noticed at low fan speeds, A/C is cool and seems to have limited effect on consumption.

Is the A/C a heat pump?

 

[dsimpkins]

UK spec isn't a heat pump. Euro is apparently.

 

[Bam Bam]

I have also noticed at low fan speeds, AC is cool and seems to have limited effect on consumption.

is the AC a heat pump?

Yes, they are essentially heat pumps, in the same way that your refrigerator is.

MG4 is described as not having a heat pump in the sense that the battery is not heated with a heat pump. This would be handy in the winter, though the UK is pretty mild most of the time so it was obviously deemed too much extra expense (for them and us) for too little gain by MG.

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I've been using the A/C recently. I virtually never did so on previous petrol cars except when in severe distress as it seemed wasteful, so I just put up with the fan.

Sometimes it is too cool! (as noted above)

It particularly cools down the door handles I find. So I've been setting it to 26 degrees and 1x fan speed once the car has cooled down.

I've also been getting over 4miles per kWh, often 4.4 in recent days, due to the heat.

 

[decrep]

Summer here, does get hot, up to 40°C with no shade, even our white car is unbearable after shopping. Using the app to tun the A/C on while we have a coffee, makes life much more pleasant.

(And the only effective way to cool a car is with refrigeration. So yes it's a heat pump. But so is an ICE car, there shouldn't be much difference in how much extra energy they use.)

 

[Tuareg]

I use A/C pretty much every time I'm in the car between May and October and June through September, daytime doesn't get below 30°C, often something like 33-38°C, can be in the 40s°C some days, normal here. Don't notice any impact on range.

 

[wattmatters]

UK spec isn't a heat pump. Euro is apparently.

Aircon (cooling) is a heat pump, what it's not is a reverse cycle heat pump which is what the euro option will be.

Summer here, does get hot

Yup. Our aircon is left on permanently, can sometimes need it in winter if the car's been in the sun. Just a matter of whether it's set to 22, 23 or 24 °C.

 

[Yandards]

Just let it do its thing, might see a kWh in 'consumer use' over a full battery but I'll take the comfort.

Remote climate is a great quality of life improvement, also use it in winter to defrost the car so I can just get in and go.

Ideal battery temperature is around 25 degrees C for optimal energy transfer, hence the high miles/kWh values at the moment.

 

[pjmmk]

A heat pump made a huge difference to the LEAF with its tiny battery. It's not as much of a deal maker (or breaker) for current EVs.

 

[MG4JP]

Using the app to tun the AC on while we have a coffee, makes life much more pleasant.

This is the way. I've been using this function so much lately... It's totally game-changing.

Also, more on-topic, I definitely notice that running the A/C during summer does not have a great impact on consumptions, which is great.

On the other hand, turning the heat on during the winter does have an huge impact.

My findings are on a Standard model (without heat pump).

 

[salty]

Never turn the A/C off, ever. Obviously vary the Temp and Fan Speed, to suit.

 

[Rolfe]

Mine tends to blow colder air when I have the A/C on, even if the temperature is set relatively high. So it goes off except on warm days.

 

[hojnikb]

A/C system uses about 300-400W when the car is cooled down. If you drive 100km/h, that's 0,4kWh/100km of extra consumption. Basically very little. And the faster you drive, the less noticable it will be actually.

You can also cheat a bit if you go on a long drive by precooling the car. That's a bit tricky, as I don't think the car will pull power from the wall, once battery is at 100%. So before you leave, charge the battery at 99%, kick the A/C on for 15 mins before you leave to max and bam, you saved some battery.


When it's hot outside, the air is thinner and as such aero drag is lower. With our cars that aren't too aerodynamic, that's a great benefit, as less aero drag will offset higher A/C consumption.

 

[MG4JP]

That's a bit tricky, as i don't think the car will pull power from the wall, once battery is at 100%.

You're right, it won't.

 

[hojnikb]

You're right, it won't.

99% trick does work well in this case. Although it is kinda useless for SE oweners (as we cant limit charge %).

I cheat a little bit and use homeassistant to automate charging stop at certain %.

 

[NickHeynes]

I was once told that using a/c (on an ice car ) used the same equivalent amount of power , as driving around with your windows and sunroof open

 

[siteguru]

That's a bit tricky, as I don't think the car will pull power from the wall, once battery is at 100%.

In my experience (testing both remote HVAC and battery heating, on my own car), those systems will draw from the battery but once the battery level falls it will kick start the EVSE to start charging again.