How does pre conditioning work?

[Fortune7]

Originally Posted by Philip Fisher

Good explanation Lexman. In addition on the T8 when plugged in it will run the AC to cool the cabin down too......

So is the A/C compressor electrically driven? Before the T8 I had a Mitsubishi Outlander PHEV which had an electrically driven A/C so it would run without the petrol engine, either plugged-in or not.

I admit I still have some confusion about the difference between Preconditioning (Parking Climate on app) and (Engine) Remote Start - which isn't working for me. If Preconditioning will run either A/C or heating (with aux. heater), then for the T8 what does Remote Start do? Is there a difference in function when plugged-in or not? My assumption - probably wrong - was that the A/C can only work when the engine is running, hence if you want pre-cooling (plugged-in or not), you use Remote Start.

When they fix the T8's remote start function I can do some experimenting but until then.......

Cheers, Andy

[Wobbly]

My understanding of preconditioning is that it’s limited without the aux heater: if there is some residual engine heat, the car will engage pre conditioning. It was also vent the car in hot weather.

The car can’t “magic up” heat from nowhere - it needs either a warm engine or a heater before it can transfer that heat to the cabin.

Try this: after your next journey (with a warm engine), lock the car then activate preconditioning via the app. I suspect it’ll work as it did with my D4.

[Fortune7]

Thanks, Wobbly, I appreciate all that and agree. I know it's off-topic, but my question is about how Preconditioning differs from Remote Start, for the T8 with heater.

Cheers, Andy

[ulstrup]

in the T8 the A/C is electrically driven. I have only tried it when the car is plugged, but then it works beautifully and the inside of the car is at 22°c (that's the default setting) I haven't tried cooling the car, for obvious reasons, but I guess it will work on the same principle.

to my knowledge the T8 has no Aux. heater since everything is controlled by the A/C.

remote start is useful to have also your seats heated if you have so programmed.otherwise I can't see any useful use of the remote start in the T8.

I don't know if anything works when unplugged.but it seems only logical that it should work provided the battery is loaded enough.

[Philip Fisher]

Originally Posted by ulstrup

in the T8 the A/C is electrically driven. I have only tried it when the car is plugged, but then it works beautifully and the inside of the car is at 22°c (that's the default setting) I haven't tried cooling the car, for obvious reasons, but I guess it will work on the same principle.

to my knowledge the T8 has no Aux. heater since everything is controlled by the A/C.

remote start is useful to have also your seats heated if you have so programmed.otherwise I can't see any useful use of the remote start in the T8.

I don't know if anything works when unplugged.but it seems only logical that it should work provided the battery is loaded enough.

I am afraid that most of the above is wrong - for UK spec T8s at least. Lexman's explanation up thread was a good explanation of how the heater works.

[Lexman8]

Originally Posted by ulstrup

to my knowledge the T8 has no Aux. heater since everything is controlled by the A/C.

Afaik all T8s have an aux heater*; it's certainly true for UK cars. An aux heater will pre-heat the engine (as well as the cabin), something that the A/C system cannot do. An aux heater also means that significant heat can be produced without starting the engine or draining the hybrid battery.

*Except in those countries where they are not allowed by law.

[SpaceBoy42]

I have no idea why the User Manual for the car is actively confusing in this area. It seems the only way you can find out how it all works is through trial and error and the forums!

I too have a UK spec T8. As has been pointed out already, there is no source of heat other than from the Aux heater if you are attempting to precondition the car to warm it up. You can start preconditioning either now or at scheduled times if you are plugged in. If you are not plugged in, the timed events don't seem to work for me but selecting "Start" to start the climate preconditioning immediately does work as long as the car thinks you have enough fuel/charge (although I've not checked this yet). Ideal for me just before I get in my car for the return journey from work (car not plugged in).

If you drive off on electric only, by default the Aux heater is switched off when you start and you are running on residual heat from the system until it cools down. This is good for short journeys but for longer ones on electric only (e.g. slow short journey in traffic jams in the cold winter), you might need to enable the "Additional heater" in the main Climate settings.

[Philip Fisher]

My timed events work perfectly even when not plugged in....

[ulstrup]

it seems that UK specs and French specs are different.

the French specS T8 got an ELECTRIC aux. heater and no petrol based
aux. heater. LEXMAN8 is right when saying that all T8 are fitted with an aux.heater but I'm not sure that the electric aux.heater works the same way than the fuel based one.since the aircon. compressor is also electric and can produce heat and cold I fail to see the logic in using an electric boiler to produce heat.... I will check with my dealer and come back on that.

regarding the remote start I still believe that the remote start, in the T8, is only useful for the seats and/or the heated screen, if fitted, and that only if the car is programmed to do so in SENSUS.

[Lexman8]

Over on Swedespeed, owners of US spec cars refer to a high-voltage coolant heater*. I'm not clear if this refers to an electrical mains fed heater (i.e. when car is plugged in) or one that that is powered by the high-voltage battery, or both. (The aux fuel-fired heater is not available in the US.)

A Volvo tech doc I have says "A fuel heater is available as an option in all markets except China, Japan, Turkey, Israel, the United States and Canada" so it's weird that French spec cars have an electrical heater, presumably the same as US cars have.

ulstrup says the A/C can run in heat-pump mode which would make sense as you'd get ~2kW of heat for each 1kW of input energy whereas a normal electrical heater would produce 1kW of heat for 1kW of input energy thus draining the hybrid battery twice as fast. The downside to this solution is that the climate system cannot heat and 'cool' at the same time. Why would you want that? Well, the air from an A/C system is dry so on a wet, miserable day it's good to have both warmed and dred air coming into the cabin to help remove excess moisture.

*A number of failures have been reported which is why it's been mentioned there.