panamamike
Posts: 120
Joined: Sat Jan 25, 2020 10:21 am

Quick loss of range after full charge?

Mon Mar 09, 2020 11:20 am

Wondering if this is normal. After a full L2 charge, I typically have to move my car to a parking spot before leaving for the day. I typically immediately a mile or 2 of reported range making a very short move from one parking spot to another lets say .1 miles. Is this normal?

alohart
Posts: 1989
Joined: Sat Nov 01, 2014 7:36 pm
Location: Honolulu, HI

Re: Quick loss of range after full charge?

Mon Mar 09, 2020 12:20 pm

Just to be clear, your car's actual range has decreased only by the distance that you actually drove. The range you're concerned about is only the range estimate that is constantly being recalculated and should be used only as an estimate because your future driving conditions cannot be foreseen. You'll go crazy if you try to figure out why this estimate changes, so you'll be happier not worrying so much about it.
Aloha,
Art

2014 BMW i3 Arravani Grey, Giga World, Tech + Driving Assist, Parking Assist, DC Fast Charging, JuiceBox EVSE

panamamike
Posts: 120
Joined: Sat Jan 25, 2020 10:21 am

Re: Quick loss of range after full charge?

Mon Mar 09, 2020 12:45 pm

alohart wrote:
Mon Mar 09, 2020 12:20 pm
Just to be clear, your car's actual range has decreased only by the distance that you actually drove. The range you're concerned about is only the range estimate that is constantly being recalculated and should be used only as an estimate because your future driving conditions cannot be foreseen. You'll go crazy if you try to figure out why this estimate changes, so you'll be happier not worrying so much about it.
I'm new to the car and trying to understand how it estimates. I thought it was intelligent and would eventually improve it's estimation of range based on driving style. Meaning it would give me a range based on driving habits/weather, being able to give me an accurate range at the start of driving. Sure, if I mash the power turn on all the extras and drive out of the norm I'd expect the numbers to change.

I've observed this particular range reporting issue rather consistently, loss of 3 miles or so off the bat with very little movement. Wondering if that's normal.

I'm asking because I don't know the state/history of my battery and looking for indications if it's behaving normally.

The range on the 2015 Rex is supposed to be 72 miles. I have yet to get anywhere near that range, even when driving conservatively with creature comforts turned off. I was hoping to do 2 round trips from home to work, 18 miles away so I could avoid daily charging, I can only do 1.5 at best. I was thought with sensible driving I would be able to get more range, but just hasn't happened.

eNate
Posts: 386
Joined: Mon Sep 09, 2019 5:33 pm

Re: Quick loss of range after full charge?

Mon Mar 09, 2020 1:04 pm

I'll add on to what Art said. Don't get in the mindset that your "Estimated Range" displayed is a reverse odometer.

As an example, I left home yesterday morning for a quick run down the hill (~2 miles away) to get coffee. Arriving downtown, my "Estimated Range" was unchanged. After driving back up the hill and parking, I had actually ADDED two miles of "Estimated Range" to the display.

That doesn't make any sense, except that the car is constantly recalculating range estimates based on recent driving history, and my previous trip was freeway miles + the drive up the hill. So in other words, it makes sense that it's not linearly traceable or strictly counting down turns of your wheels.

Your overall range, i.e. your commute to work and back, IS measurable, so I'd stick with notating that info (miles & battery %) and trying to extract what your car's actual range is.
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jadnashuanh
Posts: 4844
Joined: Thu May 22, 2014 2:07 pm
Location: Nashua, NH USA

Re: Quick loss of range after full charge?

Mon Mar 09, 2020 6:25 pm

Estimated range is a rolling average of the last 18-miles or so. It does not 'learn' your long-term habits, it only bases the range estimate on the last chunk. So, your short trip to move the car likely tried hard to bring the cabin up to temperature this time of year, and especially if you have a REx, all of those heat watts come directly from the battery. So, a short trip could suck up some watts. Batteries can flow more of their power when they're warm...so, your results are likely to change once the ambient weather rises.

Note, since the car does not know where you WILL be driving, or how you'll do it, your future results may not represent what happened last. Say you previously were driving on the interstate at a good clip, but your next trip is stop and go in the city...your estimated range will be way off.
Jim DeBruycker
2011 535i x-drive GT, 2014 i3 BEV

panamamike
Posts: 120
Joined: Sat Jan 25, 2020 10:21 am

Re: Quick loss of range after full charge?

Mon Mar 09, 2020 8:33 pm

jadnashuanh wrote:
Mon Mar 09, 2020 6:25 pm
Estimated range is a rolling average of the last 18-miles or so. It does not 'learn' your long-term habits, it only bases the range estimate on the last chunk. So, your short trip to move the car likely tried hard to bring the cabin up to temperature this time of year, and especially if you have a REx, all of those heat watts come directly from the battery. So, a short trip could suck up some watts. Batteries can flow more of their power when they're warm...so, your results are likely to change once the ambient weather rises.

Note, since the car does not know where you WILL be driving, or how you'll do it, your future results may not represent what happened last. Say you previously were driving on the interstate at a good clip, but your next trip is stop and go in the city...your estimated range will be way off.
I'm in TX and the weather temp is close to ideal, meaning I didn't have any HVAC functions on. Just the power required to literally move the car 200 or so feet. I understand all of the points you are making about the car trying to make estimate. I didn't know it was a rolling 18 miles, that's interesting. At the end of the day, all I wanted to know is if others experience this loss of a few miles right off the top.

jadnashuanh
Posts: 4844
Joined: Thu May 22, 2014 2:07 pm
Location: Nashua, NH USA

Re: Quick loss of range after full charge?

Wed Mar 11, 2020 11:14 am

FWIW, I've had the estimated range stay constant for as much as 10-miles or so because the conditions were different than when it was last used.

You'll get a better estimate if you use the nav system and put in a destination...then, it knows the roads, the speeds (at least the legal limits) and the terrain. Then, it can make a better estimate. Otherwise, it's just going by the last rolling average. It also uses that information to help determine if your trip will require a charging stop, and make suggestions on how to get to one before you run out. No destination set, the rolling average applies.
Jim DeBruycker
2011 535i x-drive GT, 2014 i3 BEV

panamamike
Posts: 120
Joined: Sat Jan 25, 2020 10:21 am

Re: Quick loss of range after full charge?

Wed Mar 11, 2020 11:35 am

jadnashuanh wrote:
Wed Mar 11, 2020 11:14 am
FWIW, I've had the estimated range stay constant for as much as 10-miles or so because the conditions were different than when it was last used.
irly
I've had that same experience too, but it's not consistent. The lost of a mile or two at the very beginning is fairly consistent.

jadnashuanh
Posts: 4844
Joined: Thu May 22, 2014 2:07 pm
Location: Nashua, NH USA

Re: Quick loss of range after full charge?

Fri Mar 13, 2020 1:38 pm

I think you'll find that the ambient temperature comes into play here a bit, too. The last estimate when you got in the car could easily have been warmer. Once you drive it, it can readjust that based on the current temperature. I've seen the estimated range drop miles from when it was in my garage, moved outside overnight, and have a vastly different estimated range when I got in the next morning since the temperature had dropped probably 40-50 degrees from the garage to sitting outside all night. If it got driven 100', that would have been the maximum.
Jim DeBruycker
2011 535i x-drive GT, 2014 i3 BEV

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