Charging curve on 2016 vs. 2019

[DepletedZPM]

Charging to the old 2016 e-Golf, I saw a characteristic curve where the car gradually accepted less power in the last 10 minutes as it approached 100% SOC. Filling up the 2019, it looks like the car doesn't ramp down, but goes straight to 0. I'm curious why I'm seeing this behavior?

Below I have URLs from to screenshots from my JuiceBox app that show these charging curves (I can't seem to make the IMG tags work in the forum).

2016 e-Golf:
https://photos.google.com/share/AF1...?key=d0F1UGhDdkNWYzlkSm1Nd0tEOWNLNC1aZmlCdDRR

I've only charged the 2019 e-Golf to 100% twice, once from the DCFC at the dealer's. Below is the charging curve recorded at home:
https://photos.google.com/share/AF1...?key=bjFRV29pOVREd25SQnBtTkFaMDhqaUdMTWRXcFZn

 

[slk23]

My 2017 doesn’t taper at all when charging at home (7kW).

 

[johnnylingo]

Can't comment on the e-Golf specifics, but just saw on the Facebook group some i3 owners are seeing the same thing comparing their 2019 40 kWh batteries vs. older models. My 2016 SE certainly tapered, as does my 2018 i3.

Guessing it's something related to newer battery technology?

 

[f1geek]

I have also noticed no AC taper on my 2017. My guess is there is more buffer at the top of the SoC, so when the indicated 100% is reached, the real pack SoC is more like 90 to 95% (?) and the charge rate does not need to taper to protect the battery. On the 24 kWh pack, for the car to get the promised range, I'm guessing VW had to have a smaller buffer at the top of the SoC, so a taper was required to protect the chemistry.

 

[miimura]

I have also noticed no AC taper on my 2017. My guess is there is more buffer at the top of the SoC, so when the indicated 100% is reached, the real pack SoC is more like 90 to 95% (?) and the charge rate does not need to taper to protect the battery. On the 24 kWh pack, for the car to get the promised range, I'm guessing VW had to have a smaller buffer at the top of the SoC, so a taper was required to protect the chemistry.

^ This. Agree 100%