Pre conditioning car and battery from the app.

[whitex]

Preheat of cabin only but due to the chemical reaction the battery will warm also. This is not the same as preheating the battery as this only occurs when a charging location is set in the PCM NAV as your destination or stopover..

Taycan has both active and passive modes of heating the battery. It also shares heat between the battery, motors, high voltage DC-DC converter, and voltage booster - Porsche calls it passive heating. See my post #15 above for details. The only difference between pre-heating for DC charging and for driving are target temperatures (see my post #14 above for those details).

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[whitex]

So just for clarity, if I set a Charging Preheat, I am preheating not only the cabin of the car, but also the battery. Is that correct?

Not sure what Charging Preheat refers to here, but if you're using the timer, then yes, both the battery and cabin get pre-heated if battery temperature is low enough.

 

[Scandinavian]

I hadn't driven my car for 4 days and it has been cold here and it was covered in ice.

The battery temperature was 3C and charge 77%

I plugged the car in and set the 1 hour preheat though I was actually leaving after 30 minutes.

My dispenser was delivering 7.2 kW, after 30 minutes the battery had been heated to 14C but the charge level had dropped to 75%.

The Webasto heater is rated at 10kW iirc so it looks like it was running flat out heating mainly the battery using more than the mains was dispensing so using a bit of the main battery as well.

I have seen very similar behaviour last year in Norway. Minus 25 C in snow storm and car was plugged in, preheating and charging with timers. And it was on a three phase 11 kW connection, car limiting factor as EVSE. Old provide up to 22 kW. It raised the temperature in the battery for sure and de iced the windows and doors. Car looked more like an igloo in the evening before.

It is of course nothing like the preheating when navigating to a DC HPC.

I guess some of the heat also came from the resistance in the battery while charging since Lithium batteries do not like the cold. But the main heat definitely came from the Webasto heater.

You can actually follow the power drawn by the heater with CarScnner. There is a separate data for that and it shows a high draw even when the cabin is warmed up in cold weather.

 

[Scandinavian]

I have a number of ways to measure, including connecting my own experimental EVSE, but for this I just used my whole house power monitoring from Sense. $199 on Amazon, connects to your distribution panel and wifi so it can show you real time consumption as well as historical usage of my home power usage. It's impossible to miss a 19kW kicking on at home, even 3-4 KW, especially that Sense is actually able to identify what device kicks in, so you can subtract known devices (it "learns" over time, it's hit or miss, for example it's never been able to identify the load sharing EVSE's, but it did in the past identify a 40A plug-in one charging a Tesla).

I was actually rather surprised that timer and manual pre-heat work differently. I expected manual pre-heat to just use shore power from the start. IMO it makes no sense to power the car heater from the battery if plugged in. Unless Porsche thought discharging the battery would generate extra heat? I seriously doubt it through, in-garage preheating is not even maxing out the 10kW onbaord heater, so they could have used it for battery preheat faster than by drawing 3-4kW from the battery. My best guess is different teams implemented the two preheat features, so they did it differently.

Did you ever get a chance to see how much power the heater used with CarScanner

 

[f1eng]

I guess some of the heat also came from the resistance in the battery while charging since Lithium batteries do not like the cold. But the main heat definitely came from the Webasto heater.

Quite.
The data I put in the OP shows a maximum draw of power from my dispenser for the whole time plugged in but no charge whatever added to the battery which makes it clear all of the power was being used by the Webasto heater to warm battery and cabin (the cabin won't need much power but the battery will)

 

[Scandinavian]

Quite.
The data I put in the OP shows a maximum draw of power from my dispenser for the whole time plugged in but no charge whatever added to the battery which makes it clear all of the power was being used by the Webasto heater to warm battery and cabin (the cabin won't need much power but the battery will)

And the main benefit from all of that is you will get a much better range in cold weather when facing a longish road trip in a warm car!

 

[Dabz]

It’s a real bugbear of mine that the car doesn’t have a “quick preheat” button or option in the console. So many times I decide to charge regardless of satnav destination and it would save time to be able to give the car 15 mins warning that I’m going to plug in to a fast public charger

 

[Gru]

Did you ever get a chance to see how much power the heater used with CarScanner

last week trip.
outside temp between 2° and 5°, initial batt. temp. at 4°.
batt. temp. slowly warms up to 18° in about 2hrs drive (on highway), then heater kicks in about 30mn before charging stop to raise batt. temp to 32°. jump to 50° is due to DC charging.
in terms of %, heater roughly used 5% to 6%, so 12 to 15km range less.

ah yes, air co was off, so heater wouldn't start to warm the cabin. it was pretty cold inside ... I wanted clean measurements ?‍

 

[Gru]

batt temp. then went slowly down to 29° (still cold outside), heater briefly starts before 2nd stop.

car was in Normal mode. I don't think Sport Plus would have triggered the heater earlier. I'll check that next time to be sure

 

[whitex]

Did you ever get a chance to see how much power the heater used with CarScanner

I did not think of that.

 

[whitex]

I've experimented with this a bit, and on my Taycan the preheat works like this:

1. If I just start preheating from the app, the car starts preheating from the battery even if plugged into an EVSE. Once the battery level drops to 1% below the set target, shore power is enabled and charging happens in parallel with the heating - car draws the full EVSE advertised power (typically 19.2kW in my garage, unless my wife's car is also charging, then 9.6kW)
2. If I set a departure timer, the car starts preheating immediately from shore power. EVSE shows a draw of ~3-4kW - much less than EVSE advertised capacity. Battery level does not drop and charging does not start (assuming the timer target is the same as regular charging, so battery starts at that target percentage already)

All these experiments were done inside my garage, so no below freezing starting temps. I've started to just set timers even if only few minutes ahead so that the car uses shore power for preheat. When temps are really low and I want to preheat the battery for a longer trip, I set a timer to preheat and and up the battery charge target - this way the car preheats and charges from 85% to say 95% (or 100% if going far) just before departure. Charging itself heats the battery too (I figure 3-4kW to the heater, so 15kW+ going into battery, 10% loss means 1.5kW heating of battery and electronics).

To add to this, yesterday I set the departure timer when temps outside were around 0C (32F) and car was colder than usual. I didn't have time to connect CarScanner but took a quick peak at the home power meter and the car was drawing 9kW- 10kW (of available 19kW which it would be using if charging the HV battery) for preheating, so probably maxing out the onboard HV heater to heat both the battery and the cabin.

It definitely helped with the consumption. According to the app, the outbound trip I averaged 2.1miles/kWh over 16 miles. On the return trip the car was preheated from battery (not plugged in), 1.7miles/kWh over the same 16 miles. The car was parked for few hours.

 

[hifi239]

It’s a real bugbear of mine that the car doesn’t have a “quick preheat” button or option in the console. So many times I decide to charge regardless of satnav destination and it would save time to be able to give the car 15 mins warning that I’m going to plug in to a fast public charger

In the US as well. For DC charging there is no reason they couldn't have had a "start preheat" and "cancel preheat" button, and an indicator that preheating was on. The CCS DCFC networks here are just not reliable enough yet to make this automatic.

 

[Scandinavian]

In the US as well. For DC charging there is no reason they couldn't have had a "start preheat" and "cancel preheat" button, and an indicator that preheating was on. The CCS DCFC networks here are just not reliable enough yet to make this automatic.

There is no technical reason why you could not have such a ”button”. That is available and works great in the BMW EV’s.

when I asked one of the Porsche Geniuses(?) in 2020, the answer from Porsche was that that was not allowed. It was a security risk? Guess it was totally made up answer.

Or maybe they knew already then that they would blow up their heaters big time

 

[Scandinavian]

To add to this, yesterday I set the departure timer when temps outside were around 0C (32F) and car was colder than usual. I didn't have time to connect CarScanner but took a quick peak at the home power meter and the car was drawing 9kW- 10kW (or of available 19kW) for preheating, so probably maxing out the onboard HV heater to heat both the battery and the cabin.

It definitely helped with the consumption. According to the app, the outbound trip I averaged 2.1miles/kWh over 16 miles. On the return trip the car was preheated from battery (not plugged in), 1.7miles/kWh over the same 16 miles. The car was parked for few hours.

It is not cold enough here where I live at the moment to try this. I looked at CarScanner yesterday while navigating to an Ionity station. The current drawn by the PTC heater was 12 to 12.75 A. Guess the heater is wired directly to the 800 volt battery to avoid conversion losses. Inlet water temperature was quickly raised to 50+ C. But that is another level of pre heating for charging of course.

I do not want to wish for cold weather just to satisfy my curiosity though!

 

[whitex]

when I asked one of the Porsche Geniuses(?) in 2020, the answer from Porsche was that that was not allowed. It was a security risk? Guess it was totally made up answer.

Pure speculation here, but it could have something to do with range ratings. I remember Tesla at some point had disabled the manual ability to turn off regenerative braking in order to keep their EPA range rating. Heating the battery might be similar, it would likely result in lower range, and some regulatory agency might have taken issue with that, given that most consumers don't read manuals and press random buttons all the time. Manual pre-heat would also not be activated at an optimum time, so either too early or too late, again, possibly resulting in reduced range and/or effectiveness of the preheat.

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