Preheat/Precool function, what is it doing?

[SergeyIndy]

I will try again, once I drain the battery to 10%. I think I was at 51% when I got there.

Today, it did what you (Chun) said it would do, it started charging at 74 kWh before climbing to 104kWh and then dropping to 62 kWh around 84%.

This is directly from Porsche on what to expect from the charging curve. This may not be exact and scientific graph, but it gives you the order of magnitude what to expect when all conditions have been met, and actually in true Porsche fashion it is on the low side of what actually happens. It is not unusual to see J1.1 Taycan peak at 295kW while only rated at 270kW max.

In short, you should see a solid 250kW up to 40% SoC if Battery Friendly is OFF, starting at <10% SoC. However, I would not do it for my own car. I use Battery Friendly ON and while this will not allow it to go over 200kW, it will hold higher rate for longer and keep the battery temp well below near max 131F, which is what happens when charge speeds reach 295kW. Time to 80% is the same in both cases, which is what matters, backed by real world data.

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[ZenicaNC]

This is directly from Porsche on what to expect from the charging curve. This may not be exact and scientific graph, but it gives you the order of magnitude what to expect when all conditions have been met, and actually in true Porsche fashion it is on the low side of what actually happens. It is not unusual to see J1.1 Taycan peak at 295kW while only rated at 270kW max.

In short, you should see a solid 250kW up to 40% SoC if Battery Friendly is OFF, starting at <10% SoC. However, I would not do it for my own car. I use Battery Friendly ON and while this will not allow it to go over 200kW, it will hold higher rate for longer and keep the battery temp well below near max 131F, which is what happens when charge speeds reach 295kW. Time to 80% is the same in both cases, which is what matters, backed by real world data.

Thanks, this is interesting information. I will head out to the garage shortly and I'll look to see if Battery Friendly is on or off. I don't recall seeing or changing that setting so it may still be in the default state.

 

[whitex]

This is the only way to precondition the HV battery in readiness for the fastest DC charging.

Well, there is also spirited acceleration. I have on occasion use this method to thaw a frozen battery during trips.

 

[SergeyIndy]

Well, there is also spirited acceleration. I have on occasion use this method to thaw a frozen battery during trips.

I believe the best method is called a yo-yo, which is where you accelerate rapidly and then decelerate rapidly since this process heats up the battery the fastest with rapid discharges and regen charges.

 

[hifi239]

I don't want to add confusion, but if my Taycan is plugged into shore power overnight, and I set the timer with precondition on a sub-freezing day, indeed the car does heat the battery to 62F. This is not in preparation for charging, of course. I am not sure if it is a side-effect of heating coolant to achieve a warm cabin for me, or if it is to heat the battery for better performance in the cold, or both.

 

[whitex]

I believe the best method is called a yo-yo, which is where you accelerate rapidly and then decelerate rapidly since this process heats up the battery the fastest with rapid discharges and regen charges.

When I accelerate fast to warm the battery, I need to decelerate before I can accelerate again without losing my license Also, not all EV's have as much regen as Taycan, especially when cold. As a matter of fact, Taycan also may not use regen for the first mile or two anyways, both because it wants to clean the mechanical brakes and because the battery is cold, so cannot accept anything close to the max 290kW. So end result is acceleration heats up the battery, than most of the slowdown is mechanical, but allows another full throttle acceleration. In some EV's some of the heat from the brakes is recovered by the heat pump, but I don't think Taycan does that.

 

[W1NGE]

You're such a ray of sunshine. People must flock to be around you.

Sarcasm is the lowest form of wit - you are excelling I must say ?

 

[W1NGE]

I don't want to add confusion, but if my Taycan is plugged into shore power overnight, and I set the timer with precondition on a sub-freezing day, indeed the car does heat the battery to 62F. This is not in preparation for charging, of course. I am not sure if it is a side-effect of heating coolant to achieve a warm cabin for me, or if it is to heat the battery for better performance in the cold, or both.

Batteries warm naturally due to the chemical reaction when used (your mobile will get warm when used a lot) and so if you have preconditioning enabled to heat the cabin (max duration is 1 hour per timer cycle) then naturally this will create heat in the HV battery as that reaction takes place.

The temperature increase is low and will have little or no impact on the car's performance. J1.2 Taycans / Macan EVs appear to run at lower battery temperatures in normal use - I did a 126 mile journey yesterday (ambient 5.5C) in a 4S Macan EV and the battery was at 10C and reached 14C by journey's end. Took it to Ionity for a volt and bolt and the battery reached 32C and maxed at 235kW charge rate.

Actual HV battery pre-conditioning takes this to the next level and aims to raise the battery temp to at least 32C (89.6F) in readiness for optimised charging at a DC charging location (must be >= 50kW). In so doing it also uses available battery capacity (obviously).

 

[W1NGE]

Well, there is also spirited acceleration. I have on occasion use this method to thaw a frozen battery during trips.

My licence is too important to me

 

[whitex]

if you have preconditioning enabled to heat the cabin (max duration is 1 hour per timer cycle) then naturally this will create heat in the HV battery as that reaction takes place.

Not quite true. The amount of heat the cabin heater draws is often not enough to significantly warm the batteries. I remember on one road trip (not a Taycan, but another EV), I engaged cabin pre-heat multiple times before I left the hotel in the morning, I was hoping to heat the battery as I needed a DC charge, since the prior night I was too tired to wait for a DC charge, just wanted to hit the pillow. I managed to melt some chocolate bars in the car with the max preheat for over an out (had to restart it after it times out), got to DC charger only a mile away, the battery still frozen, charging at 2kW instead of expected 100kW+. Took 45 minutes to warm it up. Next time I was in a similar situation, did some spirited accelerations going up and back an exit or two on a nearby highway, battery was able to accept much higher charge rate.

 

[whitex]

My licence is too important to me

Pull over on the onramp, launch from there to PSL+5. Slow down to PSL- 15 mph, speed up again. if not a lot of traffic, pull over on the side of the highway, launch from there. Etc, etc.

 

[W1NGE]

Not quite true. The amount of heat the cabin heater draws is often not enough to significantly warm the batteries. I remember on one road trip (not a Taycan, but another EV), I engaged cabin pre-heat multiple times before I left the hotel in the morning, I was hoping to heat the battery as I needed a DC charge, since the prior night I was too tired to wait for a DC charge, just wanted to hit the pillow. I managed to melt some chocolate bars in the car with the max preheat for over an out (had to restart it after it times out), got to DC charger only a mile away, the battery still frozen, charging at 2kW instead of expected 100kW+. Took 45 minutes to warm it up. Next time I was in a similar situation, did some spirited accelerations going up and back an exit or two on a nearby highway, battery was able to accept much higher charge rate.

Umm it is true - the degree of heating is close to negligible - point was to explain what happens when the HV is in use.

I think we can all accept that preheat / precondition / preclimatise (Porsche parlance) is only for the cabin and very little else.

Driving like a mad man to and fro (must be hilarious to see) with the sole intention of heating a battery prior to charging will clearly help but most folk will just wait and hope that the DC EVSE will play its role and perform this task if willing to wait.

 

[Briguy]

Umm it is true - the degree of heating is close to negligible - point was to explain what happens when the HV is in use.

I think we can all accept that preheat / precondition / preclimatise (Porsche parlance) is only for the cabin and very little else.

Driving like a mad man to and fro (must be hilarious to see) with the sole intention of heating a battery prior to charging will clearly help but most folk will just wait and hope that the DC EVSE will play its role and perform this task if willing to wait.

Well and thoughtfully put. Still i have never used my launch control on my Taycan and this exchange is inspiring me to find a suitable on ramp to crank it up.

 

[ZenicaNC]

Sarcasm is the lowest form of wit - you are excelling I must say ?

Yes, you've wounded me with an old saying that may or may not be from Oscar Wilde.

I'm so delighted you've stuck around the topic.

 

[ZenicaNC]

Not quite true. The amount of heat the cabin heater draws is often not enough to significantly warm the batteries. I remember on one road trip (not a Taycan, but another EV), I engaged cabin pre-heat multiple times before I left the hotel in the morning, I was hoping to heat the battery as I needed a DC charge, since the prior night I was too tired to wait for a DC charge, just wanted to hit the pillow. I managed to melt some chocolate bars in the car with the max preheat for over an out (had to restart it after it times out), got to DC charger only a mile away, the battery still frozen, charging at 2kW instead of expected 100kW+. Took 45 minutes to warm it up. Next time I was in a similar situation, did some spirited accelerations going up and back an exit or two on a nearby highway, battery was able to accept much higher charge rate.

I was tempted to try this the other day, I even put the car in the highest sport mode hoping for a chance to use some of the "turbo" acceleration but traffic had other plans. In my center instrument cluster on the far right, I have it set to show battery details along with g force due to acceleration.

I was hoping to see both the battery temp and the g force but I have noticed when engaging the launch control feature, that ring of information changes to a message. I'm wondering, can that information be duplicated on another screen, other than the passenger screen? I'll play around with it and see.

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