Weird 60kWh charging at 350 & 150

[dnanian]

So, it's cold here in the Northeast, but I'd been noticing that all my DC Fast Charge sessions were maxing out at about 60kWh. Thinking it was because the battery might be cold despite driving for 20-30 minutes, I set up a test, driving about 50 minutes to the Auburn MA 350kW chargers, arriving with about 11% capacity.

During that session (which connected and started flawlessly; things are getting better), I once again only reached 60kWh, only getting to about 40% capacity ni the 30 minute session.

Thinking it might be because it hadn't sufficiently warmed the battery still, I then drove to the Northborough chargers, and on their 150kW charger I again only hit about 60kW, stopping at about 70% over the 30 minutes.

Something weird seems to be going on. I can't see how the battery couldn't be warmed up after two charging sessions and 1:30 of driving... I've reached out to our service folks, but while I'm waiting, anyone have any ideas or interesting theories about what might be going on?

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[Scandinavian]

What was your battery temperature on the display?

 

[Tay Tay]

Did you set the charger destination in your NAV?

Do you have a ‘21? Those have a setting to optimize for battery life by showing down charging.

 

[dnanian]

What was your battery temperature on the display?

Doing it again right now. Even after setting the station as the destination after a two hour drive, the battery was only 60F at the start of charging.

14 minutes in, charging at 56kW and the battery is 66F.

 

[dnanian]

Did you set the charger destination in your NAV?

Do you have a ‘21? Those have a setting to optimize for battery life by showing down charging.

I did, and it’s a 2020.

 

[daveo4EV]

So, it's cold here in the Northeast, but I'd been noticing that all my DC Fast Charge sessions were maxing out at about 60 kWh. Thinking it was because the battery might be cold despite driving for 20-30 minutes, I set up a test, driving about 50 minutes to the Auburn MA 350kWh chargers, arriving with about 11% capacity.

During that session (which connected and started flawlessly; things are getting better), I once again only reached 60kWh, only getting to about 40% capacity ni the 30 minute session.

Thinking it might be because it hadn't sufficiently warmed the battery still, I then drove to the Northborough chargers, and on their 150kWh charger I again only hit about 60kWh, stopping at about 70% over the 30 minutes.

Something weird seems to be going on. I can't see how the battery couldn't be warmed up after two charging sessions and 1:30 of driving... I've reached out to our service folks, but while I'm waiting, anyone have any ideas or interesting theories about what might be going on?

FIFY - it’s KW _NOT_ kWh - the number of KW over time = KWh - 60 kw charge rate for 30 minutes is 30 kWh resulting power added to the battery (in idea no loss circumstances)

 

[dnanian]

FIFY - it’s KW _NOT_ kWh - the number of KW over time = KWh - 60 kw charge rate for 30 minutes is 30 kWh resulting power added to the battery (in idea no loss circumstances)

Yes, I realized my goof in subsequent post. Management regrets the error.

 

[Cpoarchy]

Doing it again right now. Even after setting the station as the destination after a two hour drive, the battery was only 60F at the start of charging.

14 minutes in, charging at 56kW and the battery is 66F.

It happened to me also and I think it’s weather, driving from Kentucky to Tennessee and then once the weather got to 40 degrees started charging back in the 150 range. But could be chargers.

 

[dnanian]

It happened to me also and I think it’s weather, driving from Kentucky to Tennessee and then once the weather got to 40 degrees started charging back in the 150 range. But could be chargers.

Interestingly, in the NA Charging app, the "time" circle also has the kW being requested (as far as I can tell), and it definitely was only asking for 60kW - I don't think three different charging locations were all "broken".

Not sure it's "wrong" behavior - but it is surprising that the battery, over a two hour drive, with a charger set as the destination, didn't get itself close to "optimal" charging temperature - on a real trip, I would have had to go well over the "standard" 30 minutes.

 

[daveo4EV]

it all depends on battery temperature

what was the battery temperature at the time of charging?

 

[daveo4EV]

https://www.taycanforum.com/forum/threads/how-to-battery-temperature-in-the-main-dash.2859/

 

[daveo4EV]

https://www.taycanforum.com/forum/t...my-taycan-charge-as-fast-as-i-want-it-to.779/

 

[daveo4EV]

14 minutes in, charging at 56kW and the battery is 66F.

battery Temp of less than 70F can lead to slower charge times to protect the longevity of the LiON cells - this seems appropriate given battery temperature.

 

[dnanian]

battery Temp of less than 70F can lead to slower charge times to protect the longevity of the LiON cells - this seems appropriate given battery temperature.

I understand. THe question is why, with a charge station set as the destination, with a two hour drive, wasn't the battery at an optimal temperature upon arrival at the charger. And not just once, but three times.

 

[daveo4EV]

with a two hour drive, wasn't the battery at an optimal temperature upon arrival at the charger.

I"m guessing the ambient temp was low enough that the car didn't use enough power to raise the temperature - obviously the "working load" to just run the car didn't raise the battery temp enough given environmental conditions - and porches software didn't siphon off enough extra battery power to add heat to the battery

the real issue here is there is _NO_ direct method to pre-condition the battery and "tell" the Taycan you want to warm the battery (which will reduce range) - you can kinda get it to do this via navigation to a fast charger via the Porsche PCM Navigation - but I've found that to be hit or miss as to if PorscheNAV actually "recognizes" the address you're going to is a fast charger and then choose to "pre-condition" the battery

we also lack insight/data into how much and how fast Porsche can actually raise the battery temperature given ambient conditions - to my knowledge those specifications haven't been published by Porsche - the battery is a pretty big thermal mass and we're talking about a delta off of ambient conditions for approximately 1500 lbs of thermal mass - that's not a cheap "ask" say if ambient conditions are 42F - and you need to raise the battery 75F - that's a 33F delta - which is quite a few kWh you'd need to pump into the battery to achieve 33F delta above ambient air temperature…

the real trick is how do you deterministically "force" the Taycan to precondition the battery?

and?

How much can the thermal system on the Taycan actually achieve in what time frame and at what cost to extra battery consumption?

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