Estimated full range is always LOW

[Deutsch100]

Hey everyone, Happy Sunday. I know I have posted about this before, but it is really beginning to bug me. My 2019 i3S Rex 100% full charge would almost always show around 150 miles (a few times up to 160 and a few times in the 130s with cold weather charging).

When I took delivery of my 2020 i3S, my 100% full charges would show 145-155 miles (sometimes a little higher, sometimes a little lower). For the past few months, even when warm weather charging...my 100% full charges show 119-125 miles. And this is what I am getting in real life driving if I am lucky.

Before the lead foot replies come in I will say that I am a VERY slow driver. I gently accelerate, I active regen brake for every stop, I usually never go above 70-72 mph on the freeway, and 90% of the time I drive in EcoPro or even EcoPro+. I do not remember the last time I used Comfort mode and I have only tried Sport mode 1x!

I have had my car for 6 months and it drives perfectly. I have never had a single issue or problem. No warning lights , no error messages and no glitches. My avg. driving result per the app is 3.8 mi per kWh (many times higher).

Just totally stumped why my estimated range is always so low when charging and even real life driving range is so low. I am in So. California, so our weather is basically nirvana for an EV.

 

[Anonymous]

Are you setting a departure time and setting preconditioning when you charge?

 

[Deutsch100]

Are you setting a departure time and setting preconditioning when you charge?

Only when it is cold, well California cold. What I am stumped about is when I plug my car in to charge, it shows what the full charge will be. It used to always show 145, 148, 150, 155 miles, etc. Now every time I plug in, the full charge range shows 120 something. There are lots of people on the Facebook i3 page and their 94Ah batteries display more range than me, and they are saying they get more real life range than me. I am stumped. The 4 bars representing the battery on our main instrument cluster....even in EcoPro, I am getting roughly 30-32 miles per bar!

I hate taking my car in to the dealer, since it is driving so well and I have never had a single warning, issue, error message, glitch, etc...

 

[Anonymous]

Since you have a REx, run it down until the REx kicks in, then put it on to charge with a departure time and preconditioning set, so it does a cell balance, and see if the range improves. If it doesn't, you may have a bad cell.

 

[alohart]

My avg. driving result per the app is 3.8 mi per kWh (many times higher).

The usable capacity of a 120 Ah battery pack is 37.9 kWh: 3.8 mi/kWh * 37.9 kWh = 144 mi. That would probably be at a temperature of 25 ºC (77 ºF). One of the reasons for your lower than expected range might be your rather low efficiency of 3.8 mi/kWh. The lifetime average of our 2014 BEV is 5.2 mi/kWh which is on the high side due to our mild climate and low average driving speeds. I don't pay much attention to the guess-o-meter because it doesn't do well when driving conditions vary for each trip.

 

[Deutsch100]

Since you have a REx, run it down until the REx kicks in, then put it on to charge with a departure time and preconditioning set, so it does a cell balance, and see if the range improves. If it doesn't, you may have a bad cell.

Thank you. If there was a bad cell....would there not be a warning for this, a message? I would be shocked if BMW did not program a warning if a cell failed or is failing. No?

 

[Deutsch100]

My avg. driving result per the app is 3.8 mi per kWh (many times higher).

The usable capacity of a 120 Ah battery pack is 37.9 kWh: 3.8 mi/kWh * 37.9 kWh = 144 mi. That would probably be at a temperature of 25 ºC (77 ºF). One of the reasons for your lower than expected range might be your rather low efficiency of 3.8 mi/kWh. The lifetime average of our 2014 BEV is 5.2 mi/kWh which is on the high side due to our mild climate and low average driving speeds. I don't pay much attention to the guess-o-meter because it doesn't do well when driving conditions vary for each trip.

Thanks. Many, many trips show that I got 2.5 to 2.9 kWh per mile I drive so slow, ALWAYS accelerate slowly and never go fast!

Today I drove for 30 mins, speeds under 45mph and mostly flat roads. I was in EcoPro the entire trip and I got 2.8 kWh per mile.

5.2 mi/kWh!! WOW! I have never seen that!

 

[alohart]

Many, many trips show that I got 2.5 to 2.9 kWh per mile I drive so slow, ALWAYS accelerate slowly and never go fast!

Today I drove for 30 mins, speeds under 45mph and mostly flat roads. I was in EcoPro the entire trip and I got 2.8 kWh per mile.

I assume you meant to write "mile per kWh" rather than "kWh per mile".

This low efficiency is almost certainly the key to your lower than expected range. If you haven't done so, check your tire inflation pressure. I run 10 psi over the recommended inflation pressure in hopes of protecting my tires and wheels from pothole damage (so far, so good!). This also reduces the rolling resistance and increases range. However, I can feel bumps a bit more and with a slightly smaller contact patch area, traction is probably slightly worse, so this isn't for everyone.

A dragging disk brake could also be to blame although this seems unlikely. I would think that you could detect a dragging brake by touching the center each wheel after driving. If one is noticeably warmer than the others, its brake would be suspect.

If the Batt. Kapa. max value in the service menu is near 37.9 kWh, your battery pack almost certainly couldn't have a weak cell. Unfortunately, there's no diagnostic trouble code (DTC) set when a battery cell is weak. BMW's ISTA+ maintenance software and a few Android smartphone apps can show the maximum and minimum voltages among all battery cells which would indicate whether cell imbalance is reducing the usable capacity and could indicate that one or more cells is weak.

 

[Deutsch100]

Many, many trips show that I got 2.5 to 2.9 kWh per mile I drive so slow, ALWAYS accelerate slowly and never go fast!

Today I drove for 30 mins, speeds under 45mph and mostly flat roads. I was in EcoPro the entire trip and I got 2.8 kWh per mile.

I assume you meant to write "mile per kWh" rather than "kWh per mile".

This low efficiency is almost certainly the key to your lower than expected range. If you haven't done so, check your tire inflation pressure. I run 10 psi over the recommended inflation pressure in hopes of protecting my tires and wheels from pothole damage (so far, so good!). This also reduces the rolling resistance and increases range. However, I can feel bumps a bit more and with a slightly smaller contact patch area, traction is probably slightly worse, so this isn't for everyone.

A dragging disk brake could also be to blame although this seems unlikely. I would think that you could detect a dragging brake by touching the center each wheel after driving. If one is noticeably warmer than the others, its brake would be suspect.

If the Batt. Kapa. max value in the service menu is near 37.9 kWh, your battery pack almost certainly couldn't have a weak cell. Unfortunately, there's no diagnostic trouble code (DTC) set when a battery cell is weak. BMW's ISTA+ maintenance software and a few Android smartphone apps can show the maximum and minimum voltages among all battery cells which would indicate whether cell imbalance is reducing the usable capacity and could indicate that one or more cells is weak.

YES, I meant to write "mile per kWh" rather than "kWh per mile"

I am almost certain I do not have a dragging disk brake. With tire psi I have them set to factory numbers. At first, I had them over inflated to do what you do...help protect the wheels from our awful CA streets, but the i3 does not have a comfy ride to begin with, so the firmer tires in an already firm i3S was not comfortable and it emphasizes any rattles or noises the car might make.

I have watched several Youtube videos on how to check battery health, and it looks not only complicated, but I fear doing something wrong and then having my instruments out of whack or disabling my car and then I'd have to deal with BMW Service :-O

 

[Fordychap]

Hi,
That low mi/kWh goes to the root of the issues you have @Deutsch100 , and the suggestions about dragging brakes was a good one... shame it wasn't a simple fix...
Our i3 is not a REx and as you know from our other posts together - the range is pretty good.
Our range of consumption at worst is around 3.1 mi/kWh unless I'm trying to get a take-away meal home quickly (and still warm) on deserted country roads late at night.... then I have (very rarely) seen it in the high 2's for the 5-10 miles back.
Our average today is 4.2 mi/kW - a bit lower than usual - lots of short journeys recently - due to Covid lockdown. Range shown is 178mi.
I really hope you get to the bottom of why the mi/kWh is so low.
Sending good luck and best wishes,
Happy to compare things if you think it would help.
Regards...