Be Aware When Assessing Battery Loss

[AdamVIP]

There are a bunch of threads about battery loss and I would like to point out how my car charges in a way that hinders the effort to accurately assess range loss and probably happens to your car as well.

I dont like using the range meter. I have a lead foot and the number never matches reality for my so in an effort to alleviate range anxiety I use the percentage for all my battery metering. When I charge at night it is set to stop at 80%. I have not seen it stop on 80% in several weeks time. Its usually anywhere from 81 to 83 percent when I get in.

If indeed you are like me and do not charge to 100% every night then the percentage you base your mileage readout on is likely wrong. getting 279 at 93% is different than 273 at 90%.

I suggest that from now one everyone tracking battery degradation refer back to the battery percentage at the time of the readout. There is still a margin of error there as 1% is anywhere from 0-3 miles but its more consistent than going off just mileage.

Id also be interested to know if anyone else's car charges a little over. I don't think its a flaw and probably has something to do with balancing.

 

[Joshan]

One thing to keep in mind. A battery that is truly degraded will never regain that energy.

People continually say they see the mileage go down and go back up. Degradation would not go back up. What most people attribute as degradation is actually just calibration issues.

I am not saying there is not degradation, every battery degrades over time. But most of the posts do not seem to be true battery degradation issues.

 

[SleeperService]

If I'm checking the percentage vs. miles, I'll wait for the percentage to tick down from 81% to 80% and look at the rated range RIGHT THEN. Mine also charges a bit over the set point, I've got mine at 80% and it is almost always between 81 and 83% in the morning. Right now my 80% charge is 243 rated miles.

 

[SigNC]

my car overcharges from time to time as well.

 

[Chisale]

I agree that people ought not to get so worked up about what "mileage" their car stops at for a certain percentage and that a lot of the variation has to do with cells rebalancing after the charging is complete. It's also difficult, even with the app, to get the bar to stop exactly where you want 80%, 90% ect. Finally the state of the battery during the charge, especially temperature, and the rate of charging could also have varying effects on where it signals 'stop'.