I ask and answer: Why won't my Taycan Charge as fast as I want it to?

[Schlossj]

When folks say "preconditioning" do they mean clicking "start" in the Climate section in the "Connect" app?

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[daveo4EV]

@Schlossj no the pre-conditioning being discussed here is “battery pre-conditioing” - advanced EV’s (like Tesla and Taycan) will pre-condition the battery if the vehicle’s computer “knows” you are heading to a fast charger. Normally this involves the vehicle attempting to warm/cool the battery so that when you reach the charger the overall battery temperature is more amenable to fast charging. The batteries maximum charge rate can only be achieve if the battery is the proper temperature - so the car will attempt to get the battery to this temperature to improve your fast charging session.

this normally involves running the thermal controls (heat/cool) for the battery and therefore will use extra battery power to thermally cool/heat the battery - this extra power will come at the expense of over all range since you are using the battery to both power the drive train and also electricially cool/heat the battery.

both Tesla and Taycan will pre-condition their batteries if you have a fast charger specifically entered into the navigation system - this lets the vehicle know you’re planning on charging and will implement it’s battery pre-conditioning process.

pulling into a fast charger with a particuarly cold battery (for example) 50F or less - can lower the fast charging rate by over 60% (or more) - Bolt owners have a particular problem with fast charging Bolt batteries that are 40F or lower - indicating fast charging rates that at less than L2/AC charging rates (7.68 kW or less).

the maximum charge rate is lower when the battery is cold for at least two reasons:

1. the batteries ability to accept a charge is greatly reduced - due to the thermal condition of the LiON cells - they simply can not be charged at as fast a rate - this is a electro-chemical restriction inheirant in the physics of LiON chemistry.
2. attempting to “force” a high rate of charge (overcharging) outside the batteries optimal temperature range is one of the best/fastest ways in which you can quickly/permanently severely damage a LiON battery - you WILL lose kWh capacity permanently when charging a LiON battery when it’s too cold (ask Nissan leaf owners)
   1. Porsche’s BMS (battery management software) controls the rate of charge and since it knows the battery temperature and the LiON cell characteristics it will prevent you from charging at a rate of charge that would damage the LiON cells - this is not something you as the vehicle owner directly manage, but I simply note it here that if you could overide the BMS software and overcharged a LiON battery when it was cold you would permanently damage the battery and lose capacity.

It’s not entirelly impossible to encounter a situation where the battery temperature is like 34F-42F and you’re sitting at a 350 kW charger where you’d be limping along at a 10 or 12 kW charge rate due to the very low temperature of the battery. The Porsche BMS will not let the battery charge a rate that would cause damage in these conditions.

One Bolt owner years ago simplly could not charge at a FastDC charger when the ambient temperature was -15F (we don’t know the battery temperature) - he flat bedded the vehicle to a heated garage and was able to charge the vehicle via an AC L2 charger (like the PMCC) - although until the car warmed up even the L2/AC charger initially only allowed a charge rate of 0.5 kW and gradually increased as the vehicle’s battery warmed up. After 6 hours on the L2 charger the vehicle had warmed up enough to allow fastDC charging (CCS like the Taycan) but he only got 5 kW fastDc charging vs. the Bolt’s maximum rate of about 56 kW…cold is not fast charging or LiON battery cell’s friend.

While extreme cold will not cause a LiON battery to fail, they really really do not like being cold - and their ability to charge/discharge is severely compromised in extreme temperatures (10F and below) - they will function until -40F - but they won’t like it- and discharging a LiON cell at low temperatures is not damage the battery per-say - but it’s efficiency will be severely compromised and you’ll get less capacity out of them per-mile driving - efficiency could be 1 or 1.5 mil/kWh (or worse) when driving in extremely cold temperatures -and charging will be painfullly slow.

 

[Schlossj]

@Schlossj no the pre-conditioning being discussed here is “battery pre-conditioing” - advanced EV’s (like Tesla and Taycan) will pre-condition the battery if the vehicle’s computer “knows” you are heading to a fast charger. Normally this involved the vehicle attempting to warm/cool the battery so that when you read the charger the overall battery temperature is more amenable to fast charging. The batteries maximum charge rate can only be achieve if the battery is the proper temperature - so the car will attempt to get the battery to this temperature to improve your fast charging session.

this normally involved running the thermal controls (heat/cool) for the battery and therefore will use extra battery power to thermally cool/heat the battery - this extra power will come at the expense of range.

both Tesla and Taycan will pre-condition their batteries if you have a fast charger specifically entered into the navigation system - this lets the vehicle know you’re planning on charging and will implement it’s battery pre-conditioning process.

pulling into a fast charger with a particuarly cold battery (for example) 50F or less - can lower the fast charging rate by over 60% (or more) - Bolt owners have a particular problem with fast charging Bolt batteries that are 40F or lower - indicating fast charging rates that at less than L2/AC charging rates

the charge rate is lower when the battery is cold for at two reasons:

1. the batteries ability to accept a charge is greately reduced - due to the thermal condition of the LiON cells - they simply can not be charged at as fast a rate
2. attempting to “force” a high rate of charge outside the batteries optimal temperature range is one of the ways in which you can quickly/permanently damage a LiON battery - you WILL lose kWh capacity permanently when charging a LiON battery when it’s too cold
   1. Porsche’s BMS (battery management software) controls the rate of charge and since it knows the battery temperature and the LiON cell characteristics it will prevent you from charging at a rate of charge that would damage the LiON cells

It’s not entirelly impossible to encounter a situation where the battery temperature is like 42F and you’re sitting at a 350 kW charger where you’d be limping along at a 10 or 12 kW charge rate due to the very low temperature of the battery. The BMS will not let you charge a rate that would damage the battery in these conditions.

One Bolt owner simplly could not charge at a FastDC charger when the ambient temperature was -15F (we don’t know the battery temperature) - he flat bedded the vehicle to a heated garage and was able to charge the vehicle via an AC L2 charger (like the PMCC) - although until the car warmed up even the L2/AC charger initially only allowed a charge rate of 0.5 kW and gradually increased as the vehicle’s battery warmed up.

While extreme cold will not cause a LiON battery to fail, they really really do not like being cold - and their ability to charge/discharge is severely compromised in extreme temperatures (10F and below) - they will function until -40F - but they won’t like it- and discharging a LiON cell at low temperatures is not damage the battery per-say - but it’s efficiency will be severely compromised and you’ll get less capacity out of them per-mile driving - efficiency could be 1 or 1.5 mil/kWh (or worse) when driving in extremely cold temperatures -and charging will be painfullly slow.

As always thanks @daveo4EV - so if I don't use the Nav and just roll up to a 50kW charger, is there a way to pre-condition manually?

 

[daveo4EV]

BTW: for those that live in cold climates I’d love any real world observed fastCharging rates with Battery temperature data!!!

I would simply love that.

 

[daveo4EV]

@Schlossj I’m not aware of any method with Porsche or Tesla - but I have not tried - 50 kW isn’t really an issue for Tesla or Taycan - it’s the really higher rates of charge 50 kW and above that are going to be severely compromised…

however I don’t think it would do you any good - the battery’s thermal mass is really quite large - and the batteries temperature is really quite stable - you can not quickly move the battery temperature (i.e. in an hour or less a typical fast charging session time) given it’s thermal mass

it takes quite a bit of time/power/energy to change a Taycan‘s battery 1 full degree F - so if you don’t start pre-conditioning the battery well enough ahead of time - it’s probably too late by the time you’ve arrived at the fast charger…

think swimming pool - if the pool is 62F and you want it to be 68F - you kinda have to plan that out start to raise the pool’s temperature well ahead of time - I own a 500 gallon hottub and it has a 30 amp electrical heating circuit (6 kW) - it can raise the temperature about 1.25 degree F per-hour - I like to keep it at 101F - and water coming out of the hose is about 57-60 degrees in california - you need to achieve a 45 degree raise of temperature on 500 gallons of water - if you can provide 1.25 degree hour it will take about 36 hours to achieve the target temp of 101F…you also have to factor in ambient temperature since the thermal mass (battery or water in the pool) will be naturally drawn to the ambient temperature - if the heating/cooling system is working “against” the ambient temperature it not only has to over come the inertial thermal mass temperature but has to provide “extra” power to continously compensate for the “losses” caused by the overall ambient environment…

Battery Temp: 42F
Ambient Air Temp: 31F
Target Charging Temp: 65F

the onboard heating system in the Taycan has to effect a 23F rise in temperature on ~1,500 lbs of LiOn battery cells @ 42F (quite the thermal mass) - and the trend is for the battery to seek equilibrium with ambient (31F) - so the battery and the environment is working against raising the battery’s temperature - it will take time and quite a bit of power to raise the temperature of 1,500 lbs of battery…it simply can not be done quickly.

if you are in cold/hot weather - and you’re planning to road trip and will be fast charging - it’s best to have the fast charger entered into the navigation system so that the Taycan can begin working as soon as possible to raise/lower the battery temperature to be as close to optimal as possible - short notice is not your friend here - as much time as possible ahead of time will allow the vehicle and physics to work towards achieve the target temperature…

 

[daveo4EV]

this article goes into the details of Porsche’s rather impressive and predictive battery thermal management system - moving hte battery’s temperature is slow and expensive, so prosche has investested quite a bit of hardware and software towards this system

impressive is an understatement…

https://www.electrive.com/2020/10/05/porsche-reveals-thermal-management-system-details/

Porsche has revealed more details on its predictive thermal management system developed by Porsche Engineering last year as a study. The system is designed to ensure that electric car batteries are at the optimum temperature for charging at maximum power upon arrival at the charging station.

The temperature of the battery cells plays a key role in electric cars since charging performance decreases if the cells are too cold or too hot. Until now, thermal management has basically been reactive: if the sensors measure temperatures that are too high, cooling is activated, or vice versa – if temperatures are too low, battery heating is activated.

my read of this article is we do not yet have this system in our Taycan’s - but it would be possible for porsche to add to the vehicle in a future software update…

given that read of the article - it would appear if you are planning on fast charging it’s best to let the car in on that secret by entering the fast charger into the porsche navigation system - that should ’trigger’ battery pre-conditioning and optimize your fast charge rate for when you arrive. until we have any new software from Porsche the car will not predict your fast charging needs…and battery temperature will be reactive rather than predictive.

 

[daveo4EV]

any interesting footnote to this conversation: (well at least interesting to me and mostly on topic).

Tesla Powerwalls - the wonderful whole home backup battery/solar system from Tesla (I have it in california - given PG&E it’s a great system and I love mine - we bridged a 6 hour outage last week with no disruption to my life)

You can put the batteries for Powerwalls inside or outside, but Powerwall owners in Tahoe have noted on the forums that during the winter when it’s 30F or colder outside - the Powerwalls will discharge just fine - but when they are cold they will refuse to charge from solar due to the lower temperatures - not until later in the day when the batteries have warmed up will they begin to accept a charge from the Solar system - the problem with this is the batteries can only charge from solar (regulatory requirement for the alternatvie energy rebates) and in the winter the days are shorter, the sun’s solar radiation is weaker, and if you don’t start charging the batteries until late in the day - you’ve squandered quite of a bit of opportunity cost in terms of available solar power with which to charge the Powerwall batteries…

Now the powerwall do have their own temperature regulation modules and can heat the batteries, but for some reason Tesla has not enabled this function for cold weather usage…

so batteries get really cold over night - they discharge just fine, but if it’s a particularly cold day you may not be able to recharge them from your solar system - some customers are upset about this limitation - and I agree with them.

ICE’s have pros/cons
EV’s have pros/cons

LiON batteries and cold weather is one of their weaker aspects and a serious consideration for the informed EV owner - I do not consider the cold weather issues insurmountable - but you do need to understand EV’s are compromised in extreme cold weather applications - for most people in populated area you can simply adjust your usage and be aware range is going to take a hit in cold weather, and the car will charge slower - but there is not question this is one of EV’s weakest use cases.

 

[ron_b]

I know this an old thread but how do you find out your battery temperature and if it's preconditioned or not ? I've not been able to work it out.

I've also parked next to an Ionity (part Porsche owned) charger in the UK and it can't find it to you can't navigate to it to precondition so never get decent charge rates.

The two additional ways I know of to precondition battery are:

1. Enable Sport+ mode (requires Sport Chrono package)
2. Drive in an energetic mode as you near the charger. Accelerate hard and Brake hard repeatedly (of course only if safe).

Be sure you are 10% or less SoC to get an optimal session.

 

[Schlossj]

Another question for this esteemed group - I keep "topping up" the car every time I'm below 70%...I get nervous when I see less than 150-170 miles available...am I hurting the battery? Should I get over it and let the car get all the way down to ~50 miles remaining before re-charging? Will this help long term range? Any advice on ideal charging behavior would be helpful. I do have a Porsche home charger...so don't need to go out to charge.

 

[ron_b]

Another question for this esteemed group - I keep "topping up" the car every time I'm below 70%...I get nervous when I see less than 150-170 miles available...am I hurting the battery? Should I get over it and let the car get all the way down to ~50 miles remaining before re-charging? Will this help long term range? Any advice on ideal charging behavior would be helpful. I do have a Porsche home charger...so don't need to go out to charge.

No issues topping up frequently as long as you limit the top up using Level 2 (AC charging). Do you set the charge limit to say 85%? If so all should be fine.

Related thread https://www.taycanforum.com/forum/threads/setting-up-charging-to-85-for-novice.2851/

 

[ron_b]

Recent charging sessions have not been going as expected with two problems that I am curious if others have.

1. Charging speed suboptimal in optimal conditions from what I can see.
2. Unexpected charge session termination with no errors or intervention on my part.

Note: I have reported both of these issues to Electrify America as soon as they happen. I'm waiting to hear back more from them and will let you know what I hear.

Details on #1 and #2: just this evening I was on a trip for 150 MI ending at the Gilroy Electrify America at 9% with the battery temperature at 91 F as it was preparing itself for the charging destination even though the outside temperature was 50 F.

It started out at 222 kW and stayed there till 34% when it throttled down to 200 kW and by then it was up to 109 F. As it was nearing 10 minutes I went outside the car to get a picture of the EA screen. Suddenly the charging session ended though I had touched nothing. Wanting to get at least 15 minutes of charge before getting home I attempted to restart the session using Charging NA which now did not show the charger that I had previously activated with it. I then used the Porsche Connect app and was able to start a new session and continue. The mystery here is that though my charging started now at 50%. The car was pulling 249 kW for a little while before the BMS throttled back down but even after throttling it was faster than the end of my previous session. After being on the phone with EA for nearly 10 minutes I wanted to get a screenshot so I open the driver door and suddenly the charger stopped again with just a 10 minute session and the car was at 77%. I reported all of this to Electrify America and hope they can tell me something from looking at their logs (unit 07 btw).

Before going to Central California I had also had an aborted charging session at a 150kW unit after 25min and 80% this time it stopped while I was away from the car and just walking back to it after a small walk around.
I am now concerned whether it is a vehicle issue versus a intermittent charger issue.

I have at several occasions taking my car down to 2% and once to 1% to attempt to see 270 kW. I have seen 260 kW once.

After all these issues, do I still love the car???
Yes of course. But I do not feel like letting my wife take it out if charging were ever required. It's just too temperamental right now and it's only because I have had two and a half years with a Chevy Bolt EV that I can deal with it.

I do still owe this forum a append for the receiving of my vehicle which happened on November 11th, I do plan to do that soon.

Photos before and between and after sessions below:

 

[andyd]

How did you get the charge value at the bottom of the screen to display?

Recent charging sessions have not been going as expected with two problems that I am curious if others have.

1. Charging speed suboptimal in optimal conditions from what I can see.
2. Unexpected charge session termination with no errors or intervention on my part.

Note: I have reported both of these issues to Electrify America as soon as they happen. I'm waiting to hear back more from them and will let you know what I hear.

Details on #1 and #2: just this evening I was on a trip for 150 MI ending at the Gilroy Electrify America at 9% with the battery temperature at 91 F as it was preparing itself for the charging destination even though the outside temperature was 50 F.

It started out at 222 kW and stayed there till 34% when it throttled down to 200 kW and by then it was up to 109 F. As it was nearing 10 minutes I went outside the car to get a picture of the EA screen. Suddenly the charging session ended though I had touched nothing. Wanting to get at least 15 minutes of charge before getting home I attempted to restart the session using Charging NA which now did not show the charger that I had previously activated with it. I then used the Porsche Connect app and was able to start a new session and continue. The mystery here is that though my charging started now at 50%. The car was pulling 249 kW for a little while before the BMS throttled back down but even after throttling it was faster than the end of my previous session. After being on the phone with EA for nearly 10 minutes I wanted to get a screenshot so I open the driver door and suddenly the charger stopped again with just a 10 minute session and the car was at 77%. I reported all of this to Electrify America and hope they can tell me something from looking at their logs (unit 07 btw).

Before going to Central California I had also had an aborted charging session at a 150kW unit after 25min and 80% this time it stopped while I was away from the car and just walking back to it after a small walk around.
I am now concerned whether it is a vehicle issue versus a intermittent charger issue.

I have at several occasions taking my car down to 2% and once to 1% to attempt to see 270 kW. I have seen 260 kW once.

After all these issues, do I still love the car???
Yes of course. But I do not feel like letting my wife take it out if charging were ever required. It's just too temperamental right now and it's only because I have had two and a half years with a Chevy Bolt EV that I can deal with it.

I do still owe this forum a append for the receiving of my vehicle which happened on November 11th, I do plan to do that soon.

Photos before and between and after sessions below:

 

[ron_b]

How did you get the charge value at the bottom of the screen to display?

Ahh, not obvious. But easy.
You press on the miles/min value and it toggles. Also that same technique works in the Porsche Connect app when your vehicle is charging. See this screenshot.
Note that this screenshot is from a prior charging session, not the session discussed above. The entertaining point for this session is that my car predicted I would arrive at the charger at 0%, but I made it at 1%, I did not have my wife with me in the car during this trip. Even the Boss sound system would not have been able to dround out the anxiety. I find the car is very good at its estimations and I have developed great confidence in it in only one month of ownership. However, recent charging sessions have not left me with confidence and I feel they need to be babysitted, sadly.

 

[NC_Taycan]

In one image the battery temp is over 100 deg. F after charging. IIRC, optimal temp is 85 deg. F. I have no idea the optimal range, but there has to be some upper limit where if the battery is too hot charging is reduced to protect the battery chemistry. Could be indicative of a problem with the battery cooling system (louvers, fans, pumps, etc.) but I would expect an error code in this case. So temps may be just fine. Anyone have experience with charging rate vs. battery temp?

 

[porsche_coyote]

In one image the battery temp is over 100 deg. F after charging. IIRC, optimal temp is 85 deg. F. I have no idea the optimal range, but there has to be some upper limit where if the battery is too hot charging is reduced to protect the battery chemistry. Could be indicative of a problem with the battery cooling system (louvers, fans, pumps, etc.) but I would expect an error code in this case. So temps may be just fine. Anyone have experience with charging rate vs. battery temp?

Yes. I've seen that the battery temps climb quickly at high charging rates, which is unsurprising. The maximum battery temp I've observed during charing was around 115°F, and it quickly dropped as the charging rate ramped down. That suggests to me that the cooling system probably can't remove all of the heat generated by max speed charging (in the case where I saw this the charge rate had been as high as 263kW), but can easily handle the heat from charging at closer to 150 kW.

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