Battery capacity issue

[bwilson4web]

Does anyone know if BMW has actually replaced an i3 battery under warranty because capacity degraded below 70%? If so, can you share any links to this information?

My 2014 i3 indicates a range of about 61 miles at 100%. Kappa Max indicates about 15kwh. Car is driven about 48 miles/day in N. California. I'm hoping to have the battery replaced under warranty at some point.

15/18.6 ~= 80.6%

You are going to have to abuse the battery a lot more to get to a credible, 70%.

Bob Wilson

[MKH]

My 2014 i3 indicates a range of about 61 miles at 100%. Kappa Max indicates about 15kwh. Car is driven about 48 miles/day in N. California. I'm hoping to have the battery replaced under warranty at some point.

You need to remember that number is a computer guesstimate, not an actual hard range number. When you are fully charged, set your trip-counter to zero, and use that to get a more accurate idea of your range. Be aware also, that temperature affects range. Between 60 and 70 degrees, I get my full 71 miles, which is the advertised battery range for a 2015 Rex.. Between 40 and 50 degrees, I can knock almost 10 miles off that.

[JLB2]

Right, but I haven't seen a 71 mile range since 2017. My range at 100% charge has indicated between 52 miles and 65 miles since last Summer. Its been at about 52 and 61 miles this winter. Degradation seems to be accelerating. I'm wondering at what point I can take it to BMW to have the battery replaced under warranty.

[JLB2]

Bob - The capacity dropped to 95% from 2014 to 2017 then to 80% from 2017 to 2018. I figure it'll drop to 70% by the end of 2019 or early 2020.

I'm just wondering what I have to do to get BMW to honor the warranty. They seem to be fighting it. As more and more 2014's get older, I'm sure there will be more claims. It might be helpful to everyone if we could all share experiences of making a battery warranty claim.

[websterize]

I'm just wondering what I have to do to get BMW to honor the warranty. …

You have to find a dealership willing to go to bat for you with BMWNA.

[MKH]

I'm wondering at what point I can take it to BMW to have the battery replaced under warranty.

The stated usable capacity for the 2014 i3 is 18.8 kWh. So the battery would need to degrade to 13.15 kWh to trigger a 70% threshold warranty claim. According to BMW, if the battery capacity does fall below 70% the car's telecenter actually notifies BMW the battery has issues. I think that's why dealers aren't keen on going to bat if someone claims to them that the battery needs replacing. If the car hasn't "phoned home", the battery isn't at 70%.

[Oleksiy]

That's a very convenient position indeed! BMW learned well from Nissan's mistakes - those poor guys would replace a battery as soon as the dashboard bars go below 9. But in case of BMW only dealers can say if the battery is OK or not. And it's usually OK from what I read here and other forums. You should not rely on Batt.Kapa - it doesn't mean anything, varies too much, is affected by weather and stuff. You shouldn't rely on the GOM reported range either - it depends on your driving style, ambient temperature, humidity, gradient, etc. Please trust BMW, they know better when the battery is toast

Seriously, I've read several cases of people asking dealers to check their battery condition after the range dropped to 50 miles and lower, and Batt.Kapa to 12-13. The outcomes have been the same yet - the batteries were checked and brought back to 14ish kWh or higher via some magic or parts replacement (cell supervision circuit 6 and the SME module in the recent case described in FB group post). And the batteries were OK, according to the dealers. Following

[jlangham]

That's a very convenient position indeed! BMW learned well from Nissan's mistakes - those poor guys would replace a battery as soon as the dashboard bars go below 9. But in case of BMW only dealers can say if the battery is OK or not. And it's usually OK from what I read here and other forums. You should not rely on Batt.Kapa - it doesn't mean anything, varies too much, is affected by weather and stuff. You shouldn't rely on the GOM reported range either - it depends on your driving style, ambient temperature, humidity, gradient, etc. Please trust BMW, they know better when the battery is toast

Seriously, I've read several cases of people asking dealers to check their battery condition after the range dropped to 50 miles and lower, and Batt.Kapa to 12-13. The outcomes have been the same yet - the batteries were checked and brought back to 14ish kWh or higher via some magic or parts replacement (cell supervision circuit 6 and the SME module in the recent case described in FB group post). And the batteries were OK, according to the dealers. Following

I just got my 12v battery replaced at the dealer and wanted them to check my main battery because my Battery Kappa is always in the 12 to 13 range - even though my range on the GOM often says 70ish. The dealer checked my main battery and told me that it was at 92%!!!

Of course I told them that they were full of sh!^ and that I believe soon my car will indicate that it will need replacement.

I think the dealers have all been told NOT to replace the batteries under warranty. No other way to see it with that much of a discrepancy in what the car is reporting.

So are we saying that the car has a Battery Kappa number that means absolutely nothing? If that's so, why is it even there? Why monitor it? Why display it?

I know some of you will just say it's used in the overall calculation and that other numbers/factors are there to determine what the "real" life of the battery is. I just find that kind of convenient to not have us know and ONLY the dealer. Of course, they will always say that "it's good!"

[alohart]

I just got my 12v battery replaced at the dealer and wanted them to check my main battery because my Battery Kappa is always in the 12 to 13 range - even though my range on the GOM often says 70ish. The dealer checked my main battery and told me that it was at 92%!!!

Did your dealer charge you for the Li-ion battery pack capacity test?

Batt. Kapa. max is just a calculated capacity value that varies with conditions. The only way to truly test the capacity would be to completely discharge/charge the pack and charge/discharge it under controlled conditions. BMW hasn't publicized the conditions under which the nominal usable capacity for a new battery pack was determined. It was almost certainly done at an optimum temperature and at a pretty low current, maybe lower than the pack experiences in normal driving. The capacity increases as the charge/discharge current decreases.

Apparently, BMW dealers can determine a capacity by slowly discharging and charging a battery pack (I've read over a couple of days). This capacity is almost certainly different from the Batt. Kapa. max value.

I think the dealers have all been told NOT to replace the batteries under warranty.

BMW has boasted about the modular design of the i3 battery pack which allows the replacement of a single module rather than the entire pack. I would not be surprised if BMW replaces just enough modules to increase the pack capacity to just over 70%. I don't believe that the pack warranty requires a complete pack replacement or even a replacement of modules containing new cells. Honda was using refurbished battery packs (i.e., packs whose modules contained used cells) as warranty replacement packs for our former Honda Insight.

So are we saying that the car has a Battery Kappa number that means absolutely nothing? If that's so, why is it even there? Why monitor it? Why display it?

Who knows? This is a hidden, undocumented menu not intended for i3 drivers to monitor.

I know some of you will just say it's used in the overall calculation and that other numbers/factors are there to determine what the "real" life of the battery is. I just find that kind of convenient to not have us know and ONLY the dealer. Of course, they will always say that "it's good!"

It is true that there is no instantaneous way to measure a capacity of any battery pack (many different capacities exist depending on conditions). So it would be difficult to provide an i3 driver with a definitive pack capacity.

[flyboy320]

If you have ISTA+ you can re-calibrate or re-initialize the HV battery. In the end the battery capacity does not change, it just changes or re-calibrates the GOM range and battery kappa values. Over time these values will not accurately reflect the actual battery capacity.