Remaining range increased overnight without charging?

[datoda]

I have owned my Model 3 AWD for a bit over 5 months, and the battery seems to be performing to spec. This morning, I witnessed something I haven't seen before-- the remaining range went up overnight when I left the car unplugged.

So here's what has happened since yesterday morning:
1. I started the day with 250 miles in the tank.
2. Sent kids to schools and drove to work. Down to 185 miles.
3. I left work about 7 hours later. The battery had 178 when I started driving. I found that a bit weird, given that I didn't have Sentry on. Still, I have seen that kind of vampire drain before, so I just thought my car was doing what it needed to do.
4. When I got home, the battery showed 149 miles remaining. I left it unplugged because I planned to visit a SC soon.
5. This morning, when I drove to drop off the kids. The battery showed 154 miles remaining. That's an increase of 5 miles in range!

I wouldn't mind this type of leprechaun charging (if it's indeed happening). But I am concerned about the inaccuracy in my car's range reporting. Or worse, could it be a symptom of more severe issue with the battery? Have you guys experienced something like this, or do you have an explanation for this phenomenon? Please chime in.

 

[TexasEV]

Range is an estimate, whether reported as miles or percentage, as the battery SOC can’t be measured directly. The estimate can be more or less accurate depending on recent battery charging and use patterns. The estimate can also change with different firmware updates. Ignore minor fluctuations.

 

[iaflyer]

My guess is that the battery was cold in the morning, and warmed up during the day, increasing the range slightly.

I've seen the opposite - it shows one range in the warm(ish) garage, but then when it sits in the cold when parked outside somewhere, I lose some range (just for a few hours, I'm not talking phantom drain

 

[Rocky_H]

I wouldn't mind this type of leprechaun charging (if it's indeed happening). But I am concerned about the inaccuracy in my car's range reporting. Or worse, could it be a symptom of more severe issue with the battery? Have you guys experienced something like this, or do you have an explanation for this phenomenon? Please chime in.

I've seen this reported many times before, and it's related to some shifting in temperature. The energy you can get out of a battery depends on the temperature it is. The battery management system knows this, so it will sometimes show that battery meter number number moving by around 3-5 miles or so if the car sits for a few hours, and the battery gets to cool or warm some.

 

[PoitNarf]

Just experienced this for the first time myself. I charged my 3 to 90% last night which got it to the usual 287 miles estimated range. After the charging session completed I unplugged my 3 and it sat in my driveway overnight. This morning when I got in I noticed it was showing an estimated range of 291. Drove my 5 miles to work and had 286 miles when I parked. My efficiency has gone up dramatically recently, possibly related to having the aero covers on my wheels all the time now. I had the aero covers off for my first 15 months of ownership and they've been on for the last 2 months. I'm getting around 30 Wh/mi better efficiency over my past 3000 miles compared to my 258 Wh/mi lifetime average. So I'm wondering if that is what caused the rated range calculation to adjust a bit.

 

[Kirby64]

Just experienced this for the first time myself. I charged my 3 to 90% last night which got it to the usual 287 miles estimated range. After the charging session completed I unplugged my 3 and it sat in my driveway overnight. This morning when I got in I noticed it was showing an estimated range of 291. Drove my 5 miles to work and had 286 miles when I parked. My efficiency has gone up dramatically recently, possibly related to having the aero covers on my wheels all the time now. I had the aero covers off for my first 15 months of ownership and they've been on for the last 2 months. I'm getting around 30 Wh/mi better efficiency over my past 3000 miles compared to my 258 Wh/mi lifetime average. So I'm wondering if that is what caused the rated range calculation to adjust a bit.

The car does not take your current/past efficiency into account when calculating range, so that has nothing to do with it. Tesla's only take into account estimated SOC. That can be affected by temperature and how well balanced the cells are, as well as cell voltage obviously. My guess is that you (and the OP) are experiencing increased range as a result of one of two things:
1) The batteries balanced themselves (or, well, the BMS did balancing)
2) The temperature changed (which, given it's summer, means it likely went down, closer to the ideal ~70F)

My money is on the 2nd one in both cases.