Slow charging on a j1.2 on a 350Kw charger

[SoccerMan94043]

Just did my first DC charging session and the results were disappointing at best. I wonder if the community might have some ideas of what I might have done wrong.

I preconditioned the battery and headed to the charging station (which only took 15 minutes). I arrived at the charger (EA 350kW) with 70% left in the battery, a temp of 77 degrees and charged for 30 minutes, ending at 90%. I initially got ~47kW which increased to about 55kW hours as the batter temp went up (never above 81 degrees).

A few questions:

1) Is charging just this slow from 70%? I assumed, until past 80%, I'd be flying.

2) Do I need more preconditioning? I read the battery is happiest from 85 to 95 degrees, but the J1.2 can still fast charge in much colder weather and has more of a conditioning tolerance.

3) Could it be the EA station? If so, how do you know?

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[SergeyIndy]

It is because of your high SoC of 70%. May I ask you, what is the reason to charge at 70% SoC.
Your J1.2 will issue blame the charger message if it is not giving the car the max it can accept.
Also, it has an indicator telling you if the battery is at optimal temp to receive max charge, it is on your left tube battery screen at 3 o'clock and what that max is at 9 o'clock. The J1.2 got your back.

 

[SoccerMan94043]

It is because of your high SoC of 70%. May I ask you, what is the reason to charge at 70% SoC.
Your J1.2 will issue blame the charger message if it is not giving the car the max it can accept.
Also, it has an indicator telling you if the battery is at optimal temp to receive max charge, it is on your left tube battery screen at 3 o'clock and what that max is at 9 o'clock. The J1.2 got your back.

I wanted to try DC charging on the car. Thanks!

It did predict ~50kW the entire time. On the plus side, plug and play charging worked as did the free 30 minute charging benefit.

 

[DerekS]

I agree with @SergeyIndy - this was definitely from rolling in at 70%.

Maxing out your charge rate requires 3 conditions to all line up:
1. Low SoC (15% or less)
2. Preconditioned battery
3. A good charger that actually works at full rate, which is always a crapshoot on Electrocute America.

I’ve found the Coleman Landing charger by SJC will give around 270, but appears to be limited to that.

I‘ve had best speeds so far at the EVSlow station in Los Gatos, which delivered 317kW for the bulk of the charging curve.

 

[AutoX]

I agree with @SergeyIndy - this was definitely from rolling in at 70%.

Maxing out your charge rate requires 3 conditions to all line up:
1. Low SoC (15% or less)
2. Preconditioned battery
3. A good charger that actually works at full rate, which is always a crapshoot on Electrocute America.

I’ve found the Coleman Landing charger by SJC will give around 270, but appears to be limited to that.

I‘ve had best speeds so far at the EVSlow station in Los Gatos, which delivered 317kW for the bulk of the charging curve.

Even at 70%, I would expect to get 100kW. Everything else was pretty optimized.

 

[DerekS]

Even at 70%, I would expect to get 100kW. Everything else was pretty optimized.

I wouldn’t.

I did a charge from 75% recently and only got 45kW. My purpose wasn’t speed charging but to confirm plug-and-charge after a minor Porsche ID mixup.

 

[SergeyIndy]

Even at 70%, I would expect to get 100kW. Everything else was pretty optimized.

I would guess that the charger itself may be programmed to taper off. However, the car should be able to take a much higher rate, per mothership data graph below. They do not make it really well labeled but there is a 300kW on Y axis and you can assume X axis is from 0% to 100%. Then if you follow J1 II curve it can be as high as 200kW. I would like to see a real-world example if it is any way close to this.

 

[kern417]

Maxing out your charge rate requires 3 conditions to all line up:
1. Low SoC (15% or less)
2. Preconditioned battery
3. A good charger that actually works at full rate, which is always a crapshoot on Electrocute America.

i'm new here so maybe this is a common trope, but "electrocute america" genuinely made me lol

 

[SoccerMan94043]

I wouldn’t.

I did a charge from 75% recently and only got 45kW. My purpose wasn’t speed charging but to confirm plug-and-charge after a minor Porsche ID mixup.

Where is that report you posted from?

 

[DerekS]

Where is that report you posted from?

An app I made called Chargey for tracking EV expenses, charging details, and road trips.
Nobody liked it but me, so I pulled it from the App Store.

 

[anonymouse]

As you are in a J1.2, the nice new battery screen will show you the maximum power that the vehicle can accept given its state of charge and temperature. This is very helpful in determining whether it is your vehicle or the charge provider that is throttling.

 

[refazi]

All EA stations in our busy bay area are power shared, so it would be rare to see over 175kw rates and sometimes the stations are running on derated mode on purpose..
EAs reliability has improved over the years but it's still not great, hopefully the next generation of their all in one dispensers will roll out soon that will be at least 200kw with 50kw granularity to share between the ports.
If you come by the SFO airport try the BP Pulse station, these work well and fast if the car is fully preconditioned, which is very easy to see on the charging gauge on the dash in the J1.2

 

[AutoX]

Does ambient temp affect charging rate if the battery is already at optimum temp?

I've noticed on my J1.1. that it charges much slower on cold mornings, even though my battery temp was at optimum temp.

 

[SoccerMan94043]

Does ambient temp affect charging rate if the battery is already at optimum temp?

I've noticed on my J1.1. that it charges much slower on cold mornings, even though my battery temp was at optimum temp.

for J1.2, this articles says it's got a wider prime charging range: https://insideevs.com/news/781386/porsche-taycan-battery-secrets/

To boost charging speeds, Porsche added new bus bars—thick metal strips that move current through the pack—allowing more electricity to flow at once. As a result, the 10-80% fast-charging time dropped from 21.5 minutes to 18 minutes. The minimum battery temperature for fast charging also fell from 77 degrees Fahrenheit (25 degrees Celsius) to 59F (15C), which means drivers in colder regions can start fast charging sooner and save a few extra minutes while the battery preconditions.

 

[prj]

for J1.2, this articles says it's got a wider prime charging range: https://insideevs.com/news/781386/porsche-taycan-battery-secrets/

"Fast charging range" is a very bad marketing buzzword combination.
Realistically it still needs the battery well over 25C to get the max speed.
However, because the heater is something like 2.5x as powerful now compared to before, it gets to the optimal temperature much quicker.
Furthermore, the battery chemistry allows faster charging speeds, and also somewhat faster charging speeds at lower temperatures, but not significantly so.
Most of the 37min->18min gain when plugging in at 15C comes from the new stronger heater.

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