Battery charges to 80% then jumps to 83% 30 mins later

[gottagofast]

Is it less than 70%? If not, nothing can be done, just live with it and enjoy the car as opposed to worrying about it. I really don't know, nor care what the current degradation of either of my cars batteries are, because I know that I can get where I want to. And even 20% difference isn't going to change anything that I do.

I get that it’s just strange to me my degradation calculation is different at 50% than it is when it’s at 80%, almost 2% difference between the 2 seems kinda big to me

 

[davewill]

I get that it’s just strange to me my degradation calculation is different at 50% than it is when it’s at 80%, almost 2% difference between the 2 seems kinda big to me

Nope, just par for the course.

 

[ewoodrick]

I get that it’s just strange to me my degradation calculation is different at 50% than it is when it’s at 80%, almost 2% difference between the 2 seems kinda big to me

Or maybe just think of it this way. The way that you are calculating degradation is wrong.

 

[gottagofast]

Or maybe just think of it this way. The way that you are calculating degradation is wrong.

What’s the proper way other than looking at my range and figuring the % from when it was new

 

[ewoodrick]

What’s the proper way other than looking at my range and figuring the % from when it was new

Don't worry about it. That's the proper way.

 

[AAKEE]

So is it really at 80% and it’s just displaying 83%? Or is it actually at 83% I’m confused

Is it telling me my range at 80% is higher than it thought it was before

Whats hapoening os that the BMS has s overestimation of the battery capacity.

During charge/driving the SOC can not be measured, only calculated.

Say you set the charge to 80%.

Currently you have 30% so 50% need to be added.
The BMS calculates how much that need to be ”filled” by for example estimating the capacity to 80kWh.

For a 80kWh battery we need 40kWh to fill up 50%. (Disregard the buffer for this explanation). This value is actually possible to read from the BMS with Scan My Tesla (”to charge complete”)

So the car fills up 40 kWh but can not measure the real SOC during the charge.
(SOC is measured by the OCV / resting voltage).

After the charge the OCV is possible to read and the BMS finds the SOC to be 83%, and updates the screen with that.

If the real capacity is ~76 kWh, a 40kWh rechsrge would end up in a 53% ”refill”.
The BMS Overestimete causes this.

Do yourself a favour, next time you drive a bit longer, note the SOC at parking. (Sentry off).
Then go out to the car about 30-45 min after the drive and check the SOC again.

If I’m right, the SOC will seem to drop during this period.
(Need a longer drive to overcome the roubding of SOC to whole numbers. With scan my tesla we can se it with 0.1% resolution. It might be posdible to note the range also and look at the range dekta during these 45 minutes, better resolution)

 

[cmaster]

You will gain miles when the car is warmed to optimal operating temperature.

The temperature affects the electrical resistance of the battery. Simple as that. You get optimal miles in optimal temperature. Our brains do not work as fast as computers calculating. That's the gist of it.

 

[gottagofast]

Whats hapoening os that the BMS has s overestimation of the battery capacity.

During charge/driving the SOC can not be measured, only calculated.

Say you set the charge to 80%.

Currently you have 30% so 50% need to be added.
The BMS calculates how much that need to be ”filled” by for example estimating the capacity to 80kWh.

For a 80kWh battery we need 40kWh to fill up 50%. (Disregard the buffer for this explanation). This value is actually possible to read from the BMS with Scan My Tesla (”to charge complete”)

So the car fills up 40 kWh but can not measure the real SOC during the charge.
(SOC is measured by the OCV / resting voltage).

After the charge the OCV is possible to read and the BMS finds the SOC to be 83%, and updates the screen with that.

If the real capacity is ~76 kWh, a 40kWh rechsrge would end up in a 53% ”refill”.
The BMS Overestimete causes this.

Do yourself a favour, next time you drive a bit longer, note the SOC at parking. (Sentry off).
Then go out to the car about 30-45 min after the drive and check the SOC again.

If I’m right, the SOC will seem to drop during this period.
(Need a longer drive to overcome the roubding of SOC to whole numbers. With scan my tesla we can se it with 0.1% resolution. It might be posdible to note the range also and look at the range dekta during these 45 minutes, better resolution)

Since it over estimated that means I used less miles for my commute than it thought I did?

So I used 47% for my commute and it thought I used 50%? Then it put 50% back into the battery then when it finished it realized my total charge was 83%

 

[ewoodrick]

Since it over estimated that means I used less miles for my commute than it thought I did?

So I used 47% for my commute and it thought I used 50%? Then it put 50% back into the battery then when it finished it realized my total charge was 83%

Come back after 6 months when you've got range anxiety behind you.

No matter how you calculate it, the match isn't going to add up to the decimal point. It just isn't