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Preconditioning- Do we know for sure what's going on?

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17K views 35 replies 12 participants last post by  Zouf  
L
#1 ·
What I'm referencing here is when plugged in to our home Level 2 charger, is a) pre-conditioning feeding off the house current and not the traction battery and b) is pre-conditioning impacting both the interior of the E-tron and bringing up the temperature of the traction battery to its 'happy level'?

I couldn't find anything in the manual about this other than preconditioning impacting interior cabin temperatures.
 
J
#3 ·
Like you, I have not found any reference to exactly what is happening to the battery. From what I have read and observed:

1) if you are doing an immediate charge at home, then after the charger shuts down then no conditioning of the battery is happening. While the battery is charging, it will be getting warmed a little by the charging process itself;

2) if you set up a timed charge and include cabin conditioning using the MyAudi app, then while it is charging there will be some warming of the battery. When the cabin conditioning on a timer starts up, one of its advantages (over a quick conditioning) is that it draws power from the wall so that it does not deplete the battery to warm the cabin. However, Discussions on other threads show that this is not quite what happens. When the cabin conditioning starts, it pulls power from the battery. Once the battery drops about 1% in state of charge, the battery starts to charge again getting back up to the desired full SOC. This keeps cycling through while the cabin is conditioned. The battery will get a little more warming from these small charging cycles.

3) if you start up immediate cabin conditoning, the car uses the resistive heaters, which will draw on the battery. So, the battery will get a little warming from the energy drain.

4) if the car is plugged in, but no charging is occurring, there is no feature that allows for warming the battery in the idle car.

Ultimately, to me, the only real gain comes from the timed charge with preconditioning. In that case the cabin is warmed without depleting the battery (that is, unless you get in just before it drops down to that 1% desired SOC) and the battery is warmed a bit by starting the charge so that it completes charging close to your departure time AND while this little 1% recycling is going on.
 
#6 ·
Yan said:
I can confirm that during pre-conditioning fully charged car starts consuming energy from the house at about 1kwh, which is not consistent with charging
Click to expand...
Same here, the draw rate is too low for a battery charge and it is consistent with the A/C draw (expected value) to reach the interior cabin conditions in expected time (30 minutes). Put it differently, it is a small space heater running full swing (about 1kWh draw).
 
L
#5 · (Edited)
JNealCox, it’s interesting, in reading your description on how the battery can drop 1% while preconditioning, and then start charging again, it almost sounds like the ping ponging that’s going on for many of us when we get the endless charging alerts. I know you’re probably only talking about one or two cycles, but it is interesting.
 
#10 ·
It's a single schedule per weekday as far as I see. The eTron timer works in reverse though so you cannot control the start but rather the end when you want the car done charging. If it allowed to set the start and end it would work much better.
 
#14 ·
You can start you charging session late at night but do not end early - the car will change rather quickly and stop the draw itself.
The it'll do pre-conditioning
The idea it that you really only need a schedule for the --start-- of charging, not to end it (car will do it by itself)
 
L
#15 ·
Yan, if I don’t set a desired cabin temperature, but just a start time from a ChargePoint charger, will battery preconditioning start after the battery reaches 80% as I’ve set the peak charge to be? Or do I need to tell the car to set a cabin temperature in order for it also to precondition the battery?
 
J
#16 ·
I'm not sure how the "draw from the wall" cabin conditioning should work if you are setting it up through the 3rd party charger. Using the MyAudi app, the "draw from the wall" cabin conditioning is not tied to when the full SOC has been reached, but rather to the departure time you put into the timer in the app. I find my charging completes close to an hour before the departure time, but the condition starts a little before the departure time...a gap of 45 minutes or so.
 
L
#18 ·
Thanks guys, so 2 questions...actually 2 question and one concern:
1. When the interior of the car is being preconditioned, I’m assuming that’s when the battery is getting preconditioned?

2. I‘m also assuming if you don’t set the car’s interior temperature to some value, the battery preconditioning won’t take place? IOW are these 2 operations (interior cabin preconditioning & battery preconditioning) mutually dependent or independent?

Finally, my major concern centering around the car’s current issue with 5 minute cycling between 79% & 80%. Last night, just to see what would happen, I set the timer to charge for 5 hours, knowing all I needed was 2 hours of charging. 39 notifications later, charging stopped. Yes, an annoyance, but a real concern for a reason I’ll explain.

As a new charging cycle begins & ends (no matter how short), we’ve all heard the relays clicking & clacking. I would think going through 39 of these 5 minute cycles (even though current draw is minimal) can’t be good for the longevity of relays and whatever else is involved in a charge cycle. That’s why, until Audi comes up with a fix, I try to time the charging as close to how long I need it to get the additional miles. If I need 40 miles I set it for 2 hours. Charging to 100% as Audi suggested to avoid the issue is something I want to avoid as a workaround to the issue.
 
L
#20 ·
It's a known issue with many of the 21s according to Audi. A number of people on the forums have mentioned it. I called the E-Tron hot line and they said they've gotten many complaints about it. They've identified a software issue where the car is misreporting its status. They're confident they can come up with a fix before too long. They said drivers will be notified, probably by email, when a fix is determined.

In the meantime they're advising people to turn off alerts so that you don't get waken up in the middle of the nights by 'charge full' every 5 minutes.
 
J
#25 ·
As far as I know, there is no additional battery conditioning going on while the cabin is preconditioning, other than the slight battery self-heating due to the 1% cycling of the battery as it heats the cabin. While the car is sitting there, turned off, there is no magical source of heating that can be used to warm the battery. Only after you start driving and you start to generate waste heat from the electronics and drive train is there a source of heating to use, other than actually draining the battery to warm it up, which is counter productive.
 
C
#26 ·
Based on what I've seen with an OBD device, there isn't any pre-conditioning of the battery when the cabin is set to preheat for a departure timer.

For example yesterday morning I had the car charging 00:30-04:30am and departure timer set to 05:15am with cabin pre-heating selected as part of the timer. Ambient temperatures were around 3°c but the battery was a relatively toasty 11°c at 5:15am when I checked it at departure.

This morning the battery was charging at the same times. No preheating this time though. Ambient temperatures around 3 or 4°c again. At 7:30am the battery was 8°c having cooled off since charging stopped at 4:30am, indicating the battery temperature must have been around 10-15°c a few hours earlier. In the same zone as 'pre-heating'. I appreciate I should have taken an OBD reading at 4:30am today to see what the battery temperature was at just from charging, but I wasn't going anyway at that time...so didn't.

I don't see enough of a difference here to say that pre-conditioning takes place in the conditions I had. Maybe it does in extreme temperatures but I think the warmth I noted came from the charging process alone. Battery temperatures might have been higher if my wall charger was faster than its steady 3.6kW charge rate. At public chargers the battery temperature can be 20°c when pulling 50kW and 30°c at 120kW (observations over winter/spring).
 
J
#27 ·
Chrisechild said:
Based on what I've seen with an OBD device, there isn't any pre-conditioning of the battery when the cabin is set to preheat for a departure timer.

For example yesterday morning I had the car charging 00:30-04:30am and departure timer set to 05:15am with cabin pre-heating selected as part of the timer. Ambient temperatures were around 3°c but the battery was a relatively toasty 11°c at 5:15am when I checked it at departure.

This morning the battery was charging at the same times. No preheating this time though. Ambient temperatures around 3 or 4°c again. At 7:30am the battery was 8°c having cooled off since charging stopped at 4:30am, indicating the battery temperature must have been around 10-15°c a few hours earlier. In the same zone as 'pre-heating'. I appreciate I should have taken an OBD reading at 4:30am today to see what the battery temperature was at just from charging, but I wasn't going anyway at that time...so didn't.

I don't see enough of a difference here to say that pre-conditioning takes place in the conditions I had. Maybe it does in extreme temperatures but I think the warmth I noted came from the charging process alone. Battery temperatures might have been higher if my wall charger was faster than its steady 3.6kW charge rate. At public chargers the battery temperature can be 20°c when pulling 50kW and 30°c at 120kW (observations over winter/spring).
Click to expand...
I think you are right. For a car that is turned off, the only preconditioning (warming) the battery gets is from self-heating due to charging. If Cabin Preconditioning is turned on for the charging timer, then you get a little additional battery conditioning because the battery periodically sips a few electrons from the wall to replace those used to run the cabin heaters.
 
P
#28 ·
I am adding some comments to this subject although if also has reference to another thread "timer unnecessarily complicated" that is pertinent to this discussion.

DISCLAIMER:
I am not an Audi engineer or electrician and this is my first BEV (2021 Audi e-tron Sportback) but you may find my input to both of these topics of some value.

Basically there are two batteries in the vehicle - the 95 kWh which is the power source for the electric motors (AWD) and a 12v deep cycle. The former is recharged (in my case at home 90% plus of the time) thru a NEMA 14-50 plug on a 40 amp circuit with a 50 amp breaker. In addition it also provides recharging power to the 12v battery whenever the voltage drops below a specified level. In fact the 12v battery is actually more critical to the vehicle as it provides the only power to the vehicle's electrical system and a failure of the unit will make the car inoperable (tow truck time).

The 12v is also THE power source for the HVAC (heating and cooling).

A quick word on EVSE's:

Audi provides their own EVSE that is rated at at 9.6KW at 40 amp (real 8.8KW results) but I personally do not recommend setting the power level at 100% (switch to 50%) as the cables heat up too much for my liking.

I also have a Grizzl-e EVSE with has the same ratings but has much better cables to handle the 40 amp load and they are also slightly longer.

The rest of my comments relate more the timer software which I consider dysfunctional but will provide that input to the other thread which is more specific to that topic.

However I am providing a link to article provided by an Audi Dealer in Toronto that provides some very useful information on charging basics that you may find interesting. I have no relation to this Dealer other than being a satisfied customer.

www.audimidtowntoronto.com

E-tron Charging - Audi Midtown Toronto

Go confidently. The Audi e-tron was designed from the start as an electric vehicle without compromise. This philosophy extends equally to charging, both at home and on the road. The e-tron comes equipped with everything needed to recharge the 95 kWh battery quickly and easily. Wherever - and...
www.audimidtowntoronto.com www.audimidtowntoronto.com
 
#29 ·
PTGolf4 said:
The 12v is also THE power source for the HVAC (heating and cooling).
Click to expand...
Mostly correct, but this statement isn't.

Heating and cooling require more power than is reasonable to supply on 12V. Notice the High-Voltage Heater (PTC) and Electrical AC Compressor V470. Fans and controls are 12V as are lower power and more safety critical.

2426
 
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#33 ·
Similar experience here. I generally have the car charged to 80%, if I start the timer for the climate control after a few minutes you can see the battery level drop 1-2% (depending on the outside temperature). However, as soon as it does the battery will start topping off from the house again. Based on this I now tend to set the climate timer about 1pm is ahead of the charging timer so it has time to top-off before I head out.
 
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