Anybody ever checked charging efficiency?

Gwaihir

Well-Known Member
First Name
Ken
Joined
Jan 19, 2020
Threads
22
Messages
395
Reaction score
301
Location
UK
Vehicles
Taycan GTS ST
Country flag
My large battery was sitting at 58% And charged overnight for about 5 hours up to 84%. Checking the Zappi2 application 33.8 kW passed down the charging lead! Unless I’m mistaken, that doesn’t look that efficient? Has anybody checked the charging efficiency, especially with a cold battery - mines always outside And in this instance I would think only a few degrees above freezing.

As a further point, does anybody know what the car 0 - 100% capacity is? We know the battery capacity, but what about the usable capacity? What’s remaining at 0% and how full is indicated 100%. Knowing this would be useful to aid calculating charging efficiency.
Sponsored

 
Last edited:

sakkaro

Member
Joined
Oct 26, 2021
Threads
2
Messages
17
Reaction score
4
Location
South Korea
Vehicles
Taycan 4S & BMW 530e
Country flag
My large battery was sitting at 58% And charged overnight for about 5 hours up to 84%. Checking the Zappi2 application 33.8 kW passed down the charging lead! Unless I’m mistaken, that doesn’t look that efficient? Has anybody checked the charging efficiency, especially with a cold battery - mines always outside And in this instance I would think only a few degrees above freezing.
Most of the EVs try to maintain / bring up the battery temperature while plugged in and charging. Charging efficiency will greatly reduced if car is being charged on the outside during cold climate.

I've heard Tesla losing charge while plugged in the level 1 charging (110v charging) during freezing winter since it uses more power trying to heat up the battery than it can pull from the wall at one point.
 
OP
OP
Gwaihir

Gwaihir

Well-Known Member
First Name
Ken
Joined
Jan 19, 2020
Threads
22
Messages
395
Reaction score
301
Location
UK
Vehicles
Taycan GTS ST
Country flag
Most of the EVs try to maintain / bring up the battery temperature while plugged in and charging. Charging efficiency will greatly reduced if car is being charged on the outside during cold climate.

I've heard Tesla losing charge while plugged in the level 1 charging (110v charging) during freezing winter since it uses more power trying to heat up the battery than it can pull from the wall at one point.
Interesting point. When I looked at the discharge profile of my charger it started at 7.4kW and was flat for the full charging period. There was no sign of current draw before the charging started. If pre-heating was used I would have expected to see usage before the start time. Unless the car decided to take from the battery before charging!
 

Scandinavian

Well-Known Member
First Name
Peter
Joined
Nov 3, 2019
Threads
47
Messages
3,047
Reaction score
2,638
Location
France
Vehicles
Taycan T, Tesla M3P, Aston Martin DB9, Porsche 996 C4 Cab
Country flag
Interesting point. When I looked at the discharge profile of my charger it started at 7.4kW and was flat for the full charging period. There was no sign of current draw before the charging started. If pre-heating was used I would have expected to see usage before the start time. Unless the car decided to take from the battery before charging!
You can get an approx value by looking at your charger 7.4 kW and then check in the car how much is put into the battery. Calculate about 10% losses between what the charger says and how much the car puts into battery!

Not quite sure how the power is divided, if at all, between preheating and charging. Perhaps all goes into and being taken out of the battery.
 

W1NGE

Well-Known Member
First Name
Adrian
Joined
Jan 11, 2021
Threads
31
Messages
8,733
Reaction score
5,213
Location
Aberdeen, Scotland
Vehicles
GTS ST, Macan T
Country flag
My large battery was sitting at 58% And charged overnight for about 5 hours up to 84%. Checking the Zappi2 application 33.8 kW passed down the charging lead! Unless I’m mistaken, that doesn’t look that efficient? Has anybody checked the charging efficiency, especially with a cold battery - mines always outside And in this instance I would think only a few degrees above freezing.

As a further point, does anybody know what the car 0 - 100% capacity is? We know the battery capacity, but what about the usable capacity? What’s remaining at 0% and how full is indicated 100%. Knowing this would be useful to aid calculating charging efficiency.
Useable capacity is 83.7kWh for the PB+ (93.4kWh total capacity).

Covered in detail elsewhere on the forum.
 


B61

Well-Known Member
First Name
Bine
Joined
May 31, 2021
Threads
7
Messages
2,377
Reaction score
1,553
Location
SI
Vehicles
CT4 (9/2021)
Country flag
Useable capacity is 83.7kWh for the PB+ (93.4kWh total capacity).

Covered in detail elsewhere on the forum.
I still don't get those numbers. :angel:
If 83,7kwh is usable battery, and if (for instance) my consumption is 25kwh/100km... does it mean that my range would be 334km (from 100% to 0%)?
Advertised data for CT4 are:
- 28.1 kwh/100km
- combined WLTP range: 389-456 km

So, 83,7kwh / 28.1kwh = 298 km only...
 

W1NGE

Well-Known Member
First Name
Adrian
Joined
Jan 11, 2021
Threads
31
Messages
8,733
Reaction score
5,213
Location
Aberdeen, Scotland
Vehicles
GTS ST, Macan T
Country flag
I still don't get those numbers. :angel:
If 83,7kwh is usable battery, and if (for instance) my consumption is 25kwh/100km... does it mean that my range would be 334km (from 100% to 0%)?
Advertised data for CT4 are:
- 28.1 kwh/100km
- combined WLTP range: 389-456 km

So, 83,7kwh / 28.1kwh = 298 km only...
WLTP tests are performed at 27mph (apparently) - so wholly unrealistic.

There is no 'if' these are Porsche values.

Your math is correct (for that particular run / journey) but will differ per journey due to all the other factors - driving style, speed, weather, temperature, avg speed, no of passengers, luggage and so on.
 
  • Like
Reactions: B61
OP
OP
Gwaihir

Gwaihir

Well-Known Member
First Name
Ken
Joined
Jan 19, 2020
Threads
22
Messages
395
Reaction score
301
Location
UK
Vehicles
Taycan GTS ST
Country flag
Useable capacity is 83.7kWh for the PB+ (93.4kWh total capacity).

Covered in detail elsewhere on the forum.
Thanks, I have since checked the Porsche technical data and that states net capacity is 83.7kWh. Using this, it looks like my charging efficiency was a whopping 65%! Something I’ve never checked before. . . .
 


Jhenson29

Well-Known Member
First Name
Jeremy
Joined
Feb 9, 2021
Threads
35
Messages
2,770
Reaction score
4,124
Location
St. Louis, MO
Vehicles
2016 Macan S; 2021 Taycan 4S; 2023 911 GTS Cab
Country flag

ron_b

Well-Known Member
First Name
Ron
Joined
Dec 30, 2019
Threads
327
Messages
1,587
Reaction score
1,677
Location
SF Bay Area, USA
Vehicles
2020 Taycan 4S
Country flag
I still don't get those numbers. :angel:
If 83,7kwh is usable battery, and if (for instance) my consumption is 25kwh/100km... does it mean that my range would be 334km (from 100% to 0%)?
Advertised data for CT4 are:
- 28.1 kwh/100km
- combined WLTP range: 389-456 km

So, 83,7kwh / 28.1kwh = 298 km only...
281Wh/km or 452Wh/mi is insanely high.
You would have to be going 100mph or 160km/hr to get that efficiency or be at temperature below 0C in my opinion. I reliably average 330Wh/mi or 209Wh/km and thus see ranges of 250-260mi / 400-420km. I have 20” wheels Taycan 4S+ temps avg 60F or 15.5C in 27k miles or 43k km.
 
  • Like
Reactions: B61

B61

Well-Known Member
First Name
Bine
Joined
May 31, 2021
Threads
7
Messages
2,377
Reaction score
1,553
Location
SI
Vehicles
CT4 (9/2021)
Country flag
@ron_b : that was my old comment, from November, after two months of ownership.
As I mentioned in some of my other comments, I learned that:
- low temperatures (close or below to zero) are our main enemy.
- 21" (vs 20"): probably effects on range more than 10%
- speed (constantly over 120km/h) also
- coasting is more efficient than recuperation

It looks that I'll have something between 22-25kwh/100km with 21" and 19-22 kwh/100km with 20" tires... depends on outside temperatures.
Sponsored

 
 




Top