100% charge but under 50 miles range - 2015 REx

[jmk2015rex]

I haven't been able to find much information on how much battery capacity loss to expect on an older i3. My 2015 REx shows less than 50 miles of electric range after overnight charging to 100%. My overall mileage for the car is only 31,500. Is this typical?

 

[alohart]

That's the estimated range that depends on the current temperature, how the car was driven the past 18 miles, what driving mode is selected, your driving efficiency, and probably other dependencies that aren't so clear. However, the Idaho National Laboratory measured the battery pack capacity of 4 new 2014 i3's over as long as 15 months and 12k miles. On all of the i3's, the battery pack capacity decreased at the rate of ~7.5% over 15 months and 12k miles.

The actual range of our 2014 i3 has decreased by ~15% after 5.5 years and 10k miles. Others have reported more or less actual, not estimated, range loss. It's difficult to measure actual range loss with any accuracy because of so many variables.

It's impossible to assess whether your estimated range is typical without knowing much more. In general, your estimated range has certainly been reported by other i3 owners, so this isn't an outlier.

 

[Anonymous]

What is the current temperature? As the ambient temperature drops, so does your range because of the colder battery pack. Ideal operating temp for the i3 battery pack (and most batteries) is 77 to 105 degrees.

Have you set preconditioning, which will warm the battery pack up before your departure time??

https://insideevs.com/news/325863/bmw-i3-how-preconditioning-works/

 

[jmk2015rex]

These explanations help me understand the estimated range better. It is cold here this week (nighttime lows about 30 degrees) and my recent driving has been mostly very short, local trips. I will pre-condition and see what changes I see. I'll also watch for a change in the estimated range when I charge the car after a long trip where I use eco mode. Thanks alohart and MKH.

 

[jadnashuanh]

Your worst range performance will be short trips in the winter where the vehicle cools off to ambient each time. Especially if it is a REx, all of the heat comes from resistance heaters, so one watt of heat takes one watt out of the battery (well, probably more with the fans). With the BEV and a heat pump, you might get 3W of heat for every 1W input. A longer trip, or a chance to precondition while on the EVSE will improve things.

 

[3pete]

Yep, short trips in the cold are the worst for overall efficiency. Short trips tend to have a larger percentage of the trip doing acceleration rather than 'coasting' and this hurts your efficiency. If you are using the climate control, it's similarly working hard to hit a certain temp, but there's less time for it to 'coast' and just maintain that temp once it gets there.

If you want a gut check on whether your short range is due to inefficiency or battery degradation, you could reset your trip computer and get an idea what your mi/kwh is. Anecdotally, I tend to average around 4.0 year-round but in the winter I've logged some trips as long as 10 miles all the way down at 2.5 mi/kwh. Even shorter trips have dipped down to 2.0 (granted, I had no concern for range so that's with no attempt to help the efficiency on my part).

Then if you want to get really nerdy, you could do some additional math to estimate your battery capacity. After a drive where you've measured your trip efficiency, distance, starting and ending battery % you can use the following formula:

(Trip Miles / Trip Efficiency) / (Starting Battery % - Ending Battery %)

For example, for a trip of 40 miles at 3.5 mi/kwh starting at 100% charge and ending at 22%:

(40 / 3.5) / (1 - 0.22)

=11.43 kwh used /.78 % battery used

=14.65 kwh battery capacity at 100%

Be aware that this is a rather rough estimate and can fluctuate. If you do it a few times though, it should point you to the right ballpark of battery capacity.

 

[vreihen]

Funny story. We've had a constant 62+ F temperature here for two days now, a nice break from the more normal near-freezing temperature that we had on Friday when I plugged my car in after my evening commute home. I drove 0.2 miles to the end of our street and back this afternoon, to turn my car around in the driveway. In that short distance, the guess-o-meter jumped from 59 miles to 65 miles of projected range! Yup, temperature is a factor in range.....

 

[jadnashuanh]

Setting a departure time will help, too, as long as it's plugged into an EVSE and you give it a long enough time to do its thing.

FWIW, I've driven over 10-miles and not had the range indication go down because the conditions were different than the last time it was driven.

 

[psquare]

First post again on here in a while.

Over 63k miles on our 2015 REx now and we get 60 miles displayed at 100% on a cold 5 deg C morning in the UK.

Summer morning display range tends to be around 72 miles on full charge now. That's down from 84 miles when it was new.

 

[jlangham]

First post again on here in a while.

Over 63k miles on our 2015 REx now and we get 60 miles displayed at 100% on a cold 5 deg C morning in the UK.

Summer morning display range tends to be around 72 miles on full charge now. That's down from 84 miles when it was new.

My 2014 BEV has shown 85 on GOM a couple of times here in AZ recently. Temps in AM are high 30s/low 40s F. I have a good mix of highway and city. I don't baby mine. I'm in Comfort mode on the highway, but in town mostly ECO PRO+ which is why my GOM is so high because it's usually the last 10-18 miles I drive before plugging in for the night.