[JNealCox]

I’ve noticed recently that using the comfort auxiliary heating function on the myAudi MMI app (whilst plugged in to shore power) is actually depleting the battery slightly.

This is how I can reproduce the problem:

1. Set car to 80% charge limit and plug in.
2. Leave overnight and check charge level in morning, myAudi MMI app reports 80% charge (no longer charging)
3. Initiate immediate or timed climate control, using either ‘comfort auxiliary air conditioning’ toggled on or off
4. Allow the heating/cooling to commence and then check the battery level using the myAudi MMI app after a few minutes. It should display something like 78-79% battery charge and the green light will be flashing on the car

I had always understood that preconditioning the cabin/battery would use shore power in this case rather than depleting the battery itself. I thought that the issue might be because the air conditioning pump was three phase and therefore needed to run the inverter to generate electricity from the DC battery, but I thought that there was a bypass to run the heating/cooling from AC.

With sufficient time of course the cabin will be heated and the battery will recover to 80% but it’s enough to knock a couple of percent off at least if you’re leaving in a hurry.

Anyone else notice the same behaviour or perhaps I have a fault?

PS I have a PodPoint charger

No, I think you don't quite have the mess sorted out. The only way to get the car to "precondition" the cabin while sipping from the wall to replenish the battery is when the preconditioning is part of a Timer process you have set up via the MyAudi app. If you set up a timer and include the "Precondition" option, then about 15 minutes before the entered Departure time, the car will start to heat the cabin while replenishing the battery. All other cabin preconditioning options will NOT replenish the battery, even if the car is plugged in.

In the Audi, you have 3 "conditioning" systems: 1) resistive heaters; 2) AC for cooling and dehumidifying; and, 3) heat pump for heating. When the car is fully off and idle, the heat pump cannot function, as it extracts stray heat from the battery, electronics and drive train as its means of providing heat. For a fully off and idle car, there is no heat to extract. Therefore, in a fully off and idle car, the vehicle relies either on the resistive heaters or the AC. However, the car will not pull power from the wall, unless the conditioning is part of a Timer setup.

Audi is kind of vague about all this, but is it possible that, if on a Timer, the heat pump might be able to provide some help by extracting excess heat from the recently charged battery. Overall, though, In the case of the Timer, the heat/AC works by first pulling from the battery. When the battery drops about 1%, the car recharges to full SOC. This cycle continues. The replenishing might also provide some waste heat. Still, the roll of the heat pump in all this is speculative....only Audi knows!

 

[JNealCox]

Ahoy!