How is your battery holding up?

[jadnashuanh]

Considering that the process isn't 100%, some is lost in heat, and the various cooling processes along with maintaining the computers and signalling running, that's dismal.

 

[alohart]

I have an appointment for tomorrow for my dealer to look at the i3. Hopefully they say the battery needs replacement.

I predict that you will depart your BMW dealer with a few hundred dollars less in your wallet (the battery capacity test takes many hours) and with a usable capacity that has magically increased to more than 70% of the nominal usable capacity when new thus not qualifying for a battery pack replacement under the warranty. This seems to be a common experience which makes me believe that BMW can increase the usable capacity by mucking with the battery management system (BMS). Or maybe the process of a full slow discharge followed by a full slow charge to measure the usable capacity recalibrates the BMS so that the usable battery pack capacity increases.

 

[CanisLupus]

Here's a suggestion . Set a 'Departure Time' while charging on Level 2 . Does that process warm the battery to 25 o C ? If so then that could be the best Max Kappa that you can get . We can try this test if we're wondering what our capacity is .

 

[TheMK]

As a small update, when I dropped my car off, I was quoted $150 to do the diagnosis. If the diagnosis fails, then of course that diagnostic fee is waived by the warranty.

 

[TheMK]

Okay, so I was charged $150 + tax for the battery capacity test. There was also a recall on the fuel pressure sensor that was done at the same time. I can not tell that anything has changed. My batt kappa max is still 13.8kWh. I'm going to try to do a full charge again tonight and see what happens. I'm at a loss kind of, since 13.8 is less than 80% of the original capacity. :x

Not sure where to go from here.

 

[alohart]

Okay, so I was charged $150 + tax for the battery capacity test. There was also a recall on the fuel pressure sensor that was done at the same time. I can not tell that anything has changed. My batt kappa max is still 13.8kWh. I'm going to try to do a full charge again tonight and see what happens. I'm at a loss kind of, since 13.8 is less than 80% of the original capacity. :x

What capacity did your dealer measure? Or did you get just a ">70% of the new nominal usable capacity so no warranty claim" answer? For $150, I would want a usable capacity in kWh.

 

[TheMK]

Okay, so I was charged $150 + tax for the battery capacity test. There was also a recall on the fuel pressure sensor that was done at the same time. I can not tell that anything has changed. My batt kappa max is still 13.8kWh. I'm going to try to do a full charge again tonight and see what happens. I'm at a loss kind of, since 13.8 is less than 80% of the original capacity. :x

What capacity did your dealer measure? Or did you get just a ">70% of the new nominal usable capacity so no warranty claim" answer? For $150, I would want a usable capacity in kWh.

A generic answer. I should’ve asked the service advisor more questions. I guess I can call him back tomorrow. I had to have a family member pick my car up so that made it hard to talk to someone about it.

Do you think I should call them back?

 

[Valleeboi02]

You really need to look further into it.
How many miles does your car have on it and what year is your car? A 2014 i3 with normal use should be around 17.5kw usable battery power in 2020. No way a battery as advanced as the battery in an i3 should be at 13kw, unless you've been doing lots of Level 3 charging up to 100%. That can kill a battery quickly along with lots of high temperatures.

 

[Valleeboi02]

Why not spend $5k and get a larger capacity battery? $5k is certainly cheaper than $100k plus for a Model S.. i3 owners should save at least $1k a year in the possible hopes of replacing the battery if BMW refuses to replace under warranty. $1k a year over a 5 to 6 year span seems reasonable..

For people buying these cars used from 2014, 2015 and 2016 should really look into the battery for degradation. These cars were purposely built for small Euro cities and narrow streets. 10 to 15 miles each way and in some cases with smaller cities 14 miles round trip (Paris, France).

Not good for a massive urban city like Los Angeles or London.

 

[Anonymous]

Not good for a massive urban city like Los Angeles or London.

I live in Dallas. 6.8 million population. 2015 i3, I average 12K miles a year, and my battery range is within 3 miles of when the car was new.

 

[Anonymous]

Why not spend $5k and get a larger capacity battery? $5k is certainly cheaper than $100k plus for a Model S.

$5K will get you a used battery taken from a wreck in a salvage yard, with a 30 day warranty. Then it has to be installed.

According to Dr. Christian Cozzarini, Head of Environmental Engineering at BMW, a 'new' BMW i3 battery upgrade is $16K, installed.

 

[alohart]

A generic answer. I should’ve asked the service advisor more questions. I guess I can call him back tomorrow. I had to have a family member pick my car up so that made it hard to talk to someone about it.

Do you think I should call them back?

I would want to know as much as possible. For example, if their capacity test indicated that the capacity was just over 70% of the new capacity, I would know that I could probably get a replacement battery pack before its warranty expires.

I would want to know how they measured the capacity. I have read that BMW can use a comprehensive test that discharges the battery pack and then measures the energy required to charge it fully. Or maybe the discharge capacity is measured also. That could take a couple of days to complete although the test might continue overnight.

 

[TheMK]

You really need to look further into it.
How many miles does your car have on it and what year is your car? A 2014 i3 with normal use should be around 17.5kw usable battery power in 2020. No way a battery as advanced as the battery in an i3 should be at 13kw, unless you've been doing lots of Level 3 charging up to 100%. That can kill a battery quickly along with lots of high temperatures.

My car has 50,500 miles on the odometer, and is a July 2014 build. I've done DC Fast Charge not too much, maybe 10 or so times, and never to 100%. My car is subject to both cold (below freezing) and hot (90-95 degree days) in the course of the year, but my AC compressor is strong still, so the heat should be managed.

 

[TheMK]

A generic answer. I should’ve asked the service advisor more questions. I guess I can call him back tomorrow. I had to have a family member pick my car up so that made it hard to talk to someone about it.

Do you think I should call them back?

I would want to know as much as possible. For example, if their capacity test indicated that the capacity was just over 70% of the new capacity, I would know that I could probably get a replacement battery pack before its warranty expires.

I would want to know how they measured the capacity. I have read that BMW can use a comprehensive test that discharges the battery pack and then measures the energy required to charge it fully. Or maybe the discharge capacity is measured also. That could take a couple of days to complete although the test might continue overnight.

Yeah, I'm not totally sure. I can't tell that anything was done except replace the fuel pressure sensor, wash the car, and charge/top off to 100%. I think the battery capacity is at around 73% if I'm understanding the information they've given me correctly. My service advisor couldn't answer those questions, after I called him today. I may try to call BMW USA corporate and see what happens. Not sure if/what will happen there, but the car is becoming almost unusable, since the REx will kick in on my (pre COVID-19) daily commute. I drive at 80MPH on the freeway for 40 miles every day, plus have to climb 1000 ft at the end of the round-trip journey home.

 

[alohart]

My car has 50,500 miles on the odometer, and is a July 2014 build. I've done DC Fast Charge not too much, maybe 10 or so times, and never to 100%. My car is subject to both cold (below freezing) and hot (90-95 degree days) in the course of the year, but my AC compressor is strong still, so the heat should be managed.

Unfortunately, yours is not an uncommon story for 60 Ah i3 owners. The Idaho National Laboratories bought 4 new i3 BEV's and using their advanced testing equipment, measured the usable capacities of their battery packs. Three lost 7.5% of their usable capacity after only 14 months and 12k miles. The fourth i3 lost 3.5% of its usable capacity after only 3 months and 4k miles but was either not driven for 14 months and 12k miles or the results weren't reported. That's pretty disappointing and so consistent that these probably weren't outliers.

Our 2014 i3 has been driven only 10k miles in 5.5 years. Living in Honolulu, our i3 has never experienced temperature extremes. The temperature where it has been parked 99% of its life in an apartment parking garage varies between 70º F and 78º F.

It has been DC fast charged only once from a low charge level to 80% and 3 other times for ~10 minutes each time from a low charge level. It is AC charged almost always at only 16 A. I almost always charge it to only an indicated 80% - 90% rarely charging it full and leaving it fully charged for more than a few hours. I did allow it to remain fully-charged for 3 weeks to determine whether unequal cell charge levels might be responsible for its capacity loss, but this made no difference. The battery pack has never remained at a low charge level. I occasionally allow the charge level to drop very low followed by a full charge hoping that the battery pack capacity might be calibrated to a larger value, but this has never happened.

So its battery pack has had an ideal life according to best practices. Yet it has lost more than 15% of its actual usable capacity which I can estimate by driving the same 100-mile route. This is consistent with its current 15.4 kWh Batt. Kapa. max value. What I don't know is whether the cells have actually degraded that much or whether the battery management system (BMS) has decreased the usable capacity to minimize the risk of the cells actually degrading more than the 30% warranty limit.

The fact that older versions of BMW's ISTA+ software can increase the usable capacity makes me think that the (BMS) is at least partially to blame for the capacity loss of many 60 Ah battery packs. However, this doesn't explain why some 60 Ah i3 owners claim little loss of capacity over many miles driven. Maybe there were a lot of weak 60 Ah cells installed in 60 Ah battery packs with most lucky 60 Ah i3 owners not having any of these weak cells in their battery packs. With an i3 battery pack being a single string of 96 cells connected in series, the entire pack is no stronger than its weakest cell.