Been having an issue when setting my Model 3 to charge via the app, it's usually over or under what I set it to. This last charge the battery was at 60% and I wanted it to 80%, when it finished it showed the battery at 84%. Seems like more and more it's doing this and it never used to. What can be done to fix this?
-
Want to remove ads? Register an account and login to see fewer ads, and become a Supporting Member to remove almost all ads.
Set Charging Percentage Wrong
- Thread starter Resist
- Start date
bay74
Member
I've sometimes seen a higher SOC than asked-for when charging happened during the cold night, and then later on when I drove, the battery was warmer. I think. Or something like that. Any temperature changes involved in your situation?
So, are you saying that when you set it from your App, it's not precise? Then, set it from the car.
Or, if that's not what you are saying, maybe try a 3rd party app that allows you to set the SOC level more precisely. Some of them are cheap. I think EV Watch was $1. AutoMate is $0.99 a year. Both of those AppleWatch apps allow you to set the level to the single unit level, and not round to the nearest 5% or 10%.
ucmndd
Well-Known Member
Nothing. The BMS is doing its job and adjusting its range calculation based on available data and conditions. It's normal.
This makes no sense. I didn't set it to charge for a specific range, I set it for a percentage. I have it currently set for 90% and the app shows it's stopped charging at 87%. And as I said, it never used to do this. It always used to stop charging at the exact percentage I set it at.
The BMS used to think say 50kWh is 80%, now that the battery is at 50kWh and BMS did a recalibration, it believes you lost capacity so 50kWh now represents 83% of usable capacity. Makes a lot of sense to me!
This makes zero sense! I don't care what the BMS thinks if I set it for 80%, it should show that it stopped at 80% and not 76% or 84%.
I'm never around when my car is done charging in the middle of the night, but my ASSUMPTION has always been that it stopped charging at the right percentage (e.g., 80%). Then some time after that, while the car is sleeping, measurements and re-calculation occurs and the display is updated to the newly calculated estimate (e.g., 83%). In other words, the charging is stopping at the point I set it to, but the car's estimate was off at the time and now it has been updated to something hopefully a bit more accurate (though I know it could be less accurate as well).
It's a minor annoyance that is really only noticeable because we have a digital display. If we had analog gauges, no one would notice that we're now half a needle-width closer to Full than we expected. It is annoying, however, to see my charge at 93% when it is clearly set for 90%, and given our guidance of not exceeding 90% on a regular basis it's even a little troubling.
It's a minor annoyance that is really only noticeable because we have a digital display. If we had analog gauges, no one would notice that we're now half a needle-width closer to Full than we expected. It is annoying, however, to see my charge at 93% when it is clearly set for 90%, and given our guidance of not exceeding 90% on a regular basis it's even a little troubling.
Unfortunately, there's no practical way for BMSes to know for certain how much usable energy is left in the battery pack so you're only seeing its best guess at a given time. Perhaps as battery chemistry changes in the coming decades, this won't happen, but that's the way it is!
Think about it. It doesn’t know percentages it knows kWh. So it sets an amount at that moment for 80%, charged that corresponding kWh figure, then recalibrated and reevaluated that amount after a while to correspond to 84% of what’s possible with your battery now.
bo3bdar
Member
This might be yet another new bug they've introduced. Their software is much, much worse than when I first got my car a year ago.
I charge my car at home, and also recently had it do an overcharge. First time in a years worth of home charging. I set it to 80% in car display, and it wound up at 84% after done. Because of C-19 I have very low miles, 1400, so it's pretty unlikely the BMS would need to rebalance and be this far off. Nothing else changed except for the new software, which is why I think it's probably a bug.
Similar threads
