Supercharging and kWs

[Forthedogs]

My husband is taking the 1st road trip in our new to us 2015 Model S 70. Is it normal for the kw to go down the longer it’s super charging?

 

[st50maint]

Yes, that is normal behavior.

 

[gaswalla]

most definitely

 

[ucmndd]

Yes, normal, although your absolute values there are pretty low. 40kw at ~50% suggests you might have a battery subject to charge rate limitations Tesla has recently applied to earlier packs.

 

[M3BlueGeorgia]

My husband is taking the 1st road trip in our new to us 2015 Model S 70. Is it normal for the kw to go down the longer it’s super charging?

Best not to charge over 90%, except in exceptional situations.

 

[ElectricIAC]

Yes, Normal

 

[ElectricIAC]

Here's a 30min pull on a S85 (BT85)

 

[ucmndd]

Best not to charge over 90%, except in exceptional situations.

Like road trips.

 

[Rocky_H]

This is not something that is unique to Tesla or even to electric cars. This is a function of how all lithium ion batteries have to be charged. It's just that people have never gotten the opportunity to see it in action, because most other things with a battery in them do not display the charging power or speed.

When they are very low, they can be charged much faster, but as they get more full, the power has to be slowed down to avoid damaging them. That is the nature of things.

 

[ElectricIAC]

This is not something that is unique to Tesla or even to electric cars. This is a function of how all lithium ion batteries have to be charged. It's just that people have never gotten the opportunity to see it in action, because most other things with a battery in them do not display the charging power or speed.

When they are very low, they can be charged much faster, but as they get more full, the power has to be slowed down to avoid damaging them. That is the nature of things.

Your phone battery is a clear example. 10-50% is very quick then you hit a taper and that last 20% just crawls along.

Isn't physics fun?

 

[gaswalla]

The taper is even noted on the Tesla webpage
Supercharger | Tesla

 

[Forthedogs]

Thank you all for the responses. I’m now taking the 2nd road trip and I’m trying to get a full charge. It stopped at 210 at the super charger. I plugged it in at home and it’s at a snails pace. Any tips on getting a full charge? Or should I just except the fact that I’m only going to get 210 miles for road trips?

 

[beatle]

The snail's pace is due to the "level 1" 120v circuit. That's a normal speed at that voltage. Let the car continue to charge fully. It will start to balance the modules as the state of charge gets above 93% and the effective charge rate will slow. Running the battery down to 20% first is another way to help the car calibrate and provide a more accurate SoC, though it won't actually affect how much energy you can put into the battery. Balancing, however, will allow the car to take on more energy as the "high" modules won't trigger the car to stop.

When brand new, the 70 was rated for 234 miles. With normal degradation, I'd think you'd be in the ~220 mile range now when fully charged.