2014 i3 REx - Battery Degredation

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TheNickGuy

Well-known member
Joined
Jun 13, 2015
Messages
63
I wanted to share some statistics on my vehicle, which as of this morning has 34,512 miles on it.

My specific vehicle does not have the DC Fast Charging option, which *could* affect the lifespan of batteries, so take that into account.

This morning I checked the usable capacity of my battery in the hidden service menu and it stated I have 19.4 kWh available.

That's a pretty good number in my book, I was expecting less after my research online and the figures I reviewed when looking for directions on how to access the hidden menu.

Now, for my question, I believe the warranty BMW provides on the battery is for 100,000 miles and against more than 30% capacity loss, or 70% capacity at that time. Does this figure go against the 22 kWh of the battery, or against the usable quantity of the battery? If so, what is the initial usable quantity of the battery?

Thanks!
 
TheNickGuy said:
This morning I checked the usable capacity of my battery in the hidden service menu and it stated I have 19.4 kWh available.
If you have checked the Batt. Kapa. Max. previously, what values have you read? Have you always read Batt. Kapa. Max. under certain reproducible conditions (e.g., to read it at a certain batterietemp value)?

In less than 4,000 miles of driving, our BEV's Batt. Kapa. Max. has varied by almost 2 kWh with no up or down trend over time; the values appear to be randomly scattered. I have not attempted to standardize the reading of Batt. Kapa. Max., so this could be the cause of the apparently random values.
 
Art,

No, this was my first check in the hidden menu. Just as you've done, I plan to check periodically to see if I can monitor the battery.

Which figure does BMW use for warranty purposes for battery degradation? The overall capacity when new or the usable capacity when new?

Thanks!
 
The battery kappa isn't meaningful.

I believe that the battery capacity that BMW will assess against is a complete battery discharge at a one-third C discharge rate.
 
janner said:
The battery kappa isn't meaningful.

I believe that the battery capacity that BMW will assess against is a complete battery discharge at a one-third C discharge rate.

Uhh... Sure... [insert "that went over my head" emoji]

Well, let's assume that they have their own protocol for determination of lost battery capacity, whatever it may be. That being said, will they compare it against the new capacity (22kWh) or the usable capacity when new, and what is that?

Geez, serious, this forum is all about pointing out that not everyone is an electical engineer and/or nickle and dime-ing leases...
 
TheNickGuy said:
That being said, will they compare it against the new capacity (22kWh) or the usable capacity when new, and what is that?
Because the battery management system won't allow the battery to be completely charged or discharged (thus the lower 18.8 kWh usable capacity when new), I assume that this is what would be used as the benchmark. To measure a battery pack's capacity, BMW would fully charge the battery pack using an EVSE in the normal way and then discharge it at a constant current as suggested by janner to the minimum charge level allowed by the battery management system. But of course, this is just my speculation…
 
My 2014 Rex has 56,000 miles now. This recent picture shows the GOM a little optimistic, but honestly if it's lost any range after over two years and 56k, I can't tell. I don't think BMW will have to worry about many capacity-loss warranty claims. :D

IMG_20160825_122412990_HDR.jpg
 
TomMoloughney said:
My 2014 Rex has 56,000 miles now. This recent picture shows the GOM a little optimistic, but honestly if it's lost any range after over two years and 56k, I can't tell. I don't think BMW will have to worry about many capacity-loss warranty claims. :D

That is amazing. I have a 2014 with 11K on it and I have never managed to get the GOM that high (yes it is heavier due to Rex but I haven't even managed 80). What was your efficiency on that last trip and how slow/fast do you drive?
 
FWIW, Tom's car is also a REx. Seeing a high remaining range is easier if you take a longer trip verses much shorter ones. Lots of short trips in the summer where you've got the a/c cranking does not lend itself to long range. It's maybe not as bad as heating, but it's close when your fan is producing a gale! A trip that is longer than 18-miles means that entire trip is the basis of the succeeding range estimate and would only require the initial hit of conditioning things once verses maybe 4-5 times.
 
Just gone over 23k miles and my GOM is slightly higher during summer and if last 18 miles have been driven rather conservatively. Seems to be in line with Tom's 56k mile experience.
 
epirali said:
TomMoloughney said:
My 2014 Rex has 56,000 miles now. This recent picture shows the GOM a little optimistic, but honestly if it's lost any range after over two years and 56k, I can't tell. I don't think BMW will have to worry about many capacity-loss warranty claims. :D

That is amazing. I have a 2014 with 11K on it and I have never managed to get the GOM that high (yes it is heavier due to Rex but I haven't even managed 80). What was your efficiency on that last trip and how slow/fast do you drive?

I'm not saying I can squeeze out 90 miles per charge as the GOM indicates! In favorable conditions like it is this time of year, I can reliably expect 70 to 80 miles of electric range before needing the REx. Since the EPA range rating is 72 electric miles, I can't complain. Especially after 56,000 miles. Battery degradation isn't linear, but with what I've seen so far, I don't think BMW will have many warranty claims for capacity loss. The batteries are holding up extremely well, IMO.
 
I have 2014 Bev for 25 months with over 33k miles.

The GOM indicates the same mileage as day one.
My commute is 33 miles (25 miles freeway, 8 miles local) to work each way with access to level 1 charging at work.
clipper creek level 2 charger at home.
Bev with level 3 charger option, but never used it.

I still love my the i3 as much as day one...

So far the only item performed by bmw dealer:
standard software upgrades (3 or 4 upgrades)
AC compressor replaced (would not cool)
driver window weather strip replaced (it kept popping out)
replaced all 4 tires (20 inch tires), rear tires replaced first, then the front tires replaced 6 months after rear tires


28727610963_656df191f6_b.jpg
 
foamposite1 said:
So far the only item performed by bmw dealer:
standard software upgrades (3 or 4 upgrades)
AC compressor replaced (would not cool)
driver window weather strip replaced (it kept popping out)
Have you not had the defective KLE and motor mount bolt replaced? The system software would have had to have been updated when these repairs were performed, so maybe these repairs occurred at the same time that a couple of the software updates were installed.
 
TomMoloughney said:
I'm not saying I can squeeze out 90 miles per charge as the GOM indicates! In favorable conditions like it is this time of year, I can reliably expect 70 to 80 miles of electric range before needing the REx. Since the EPA range rating is 72 electric miles, I can't complain. Especially after 56,000 miles. Battery degradation isn't linear, but with what I've seen so far, I don't think BMW will have many warranty claims for capacity loss. The batteries are holding up extremely well, IMO.

I agree, after carefully monitoring my Leaf for couple of years I have noticed no change in my BMW i3 range. I was more curious whether you are doing mostly city/slow driving or achieving 90 GOM miles from mixed driving. I realize it is not real and based on last N miles.
 
Yes, the KLE and motor mount bolt were fixed during software updates.

The break fluid was replaced once.

There were 3 or 4 times that the drivetrain malfunction light came on while driving.
The dealer either performed software update or just erased the error from memory.
All the malfunction light came on during the first 6 months of owning the car. have not had them for a while.
 
depechemode said:
how can we learn the capacity from the hidden menu?
This link describes how to access the hidden service menu and what values are reported. The reported battery capacity is "13.08 Batt. Kapa. Max.", but I am not aware of any instructions describing how to use this value correctly. Over only 4,000 miles (6,500 km) of driving, Batt. Kapa. Max. values have varied by almost 2 kWh on our 2014 i3 BEV with no up or down trend obvious (i.e., apparently a random scattering of values). So unless someone can describe a proven way to use this value (e.g., to always read this value at a certain "14.05 batterietemp" value, or just after fully charging, or after the car hasn't been driven for more than X hours), it doesn't seem very useful for measuring battery pack capacity degradation over time.
 
My 2014 BEV i3 seems to have battery degradation yet the dealer doesn't want to admit it. Granted: we had a heat spell here in Los Angeles about 2 weeks ago and my problem began after my car sat in the garage charging when the interior temp could have been around 90 degrees. I noticed, through a window to my bungalow's garage, hazard lights flashing (without the horn). I unlocked the car, the lights stopped flashing, and then relocked it. The flashing has never repeated. It was a weird, unusual experience, but the next morning- my car had a charge of 61 miles when prior to that, the car charged about 74 miles every night. Since my commute is around 50 miles round trip, and I drive fast whenever I can, I was alarmed to think that I wouldn't have at least 15 miles left on the charge when I got home - as has been the case up until the event with the lights flashing.

I took the car in to the dealer, where I was told "a problem was found with a battery" and I was told they put in a claim with BMW. Then I learned that the problem was a "safety box" which was replaced. I was told the safety box bridged 2 batteries. I just presumed the problem was solved. I trusted them and drove off only to discover that my car had a maxed-out charge of 61 miles!!! Went back to complain and was told in a rather patronizing manner that this is what batteries normally do over time. But that doesn't make sense. This was not a gradual change, it occurred suddenly and was linked to that flashing light episode in my garage.

I also have a history of the radio station changing while the car is off. I have turned on the car and the radio has changed to a Spanish-language station. I don't speak Spanish. I was told today that because they can't reproduce the problem, it doesn't exist. Yet it is well documented on videos I've shot where the station on the screen is the one I was tuned to before I left the car and the sound of Spanish-language music is playing in the background.

Really angry at BMW. The car is just 3 years old in October. I feel utterly ripped off.
 
The radio memory, and essentially, all of the computers, run off of the 12vdc battery in the car. That gets charged during the recharge cycle of the main, high voltage batteries via a DC-DC power supply, and normally maintained while driving. If the 12vdc battery is failing, you can get weird things going on since the computers won't be able to properly run or to retain data in their volatile memory. The 12vdc (about the size of a large motorcycle battery since it doesn't need to turn a starter motor) could be failing in 3-years or so and give you all sorts of misleading symptoms. People with lots of miles on their i3's have not noticed much of any battery degradation.
 
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