JLB2
Posts: 11
Joined: Fri Jan 25, 2019 9:41 am

Battery Replacement Under Warranty

Fri Jan 25, 2019 10:00 am

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.

Some posts in this forum state that they've dealers have refused to replace the battery even when capacity degraded below 13kwh which is about 70% of original. Any information about BMW honoring the warranty would be appreciated.

rtanov
Posts: 188
Joined: Mon Oct 20, 2014 10:55 am
Location: Cincinnati, OH, USA

Re: Battery Replacement Under Warranty

Fri Jan 25, 2019 2:03 pm

That Kappa Max seems low. Our 2014 REx (28k miles since Nov '14) is showing around 17 kWh (16.6 - 17.5) in the last month and temperature here have been low. Range hovers around the 50 miles due to the cold, and my wife's commute is also 48 miles one way - she can consistently charge at work. I have not heard of a battery being replaced under warranty but have seen some complaints for low Kappa Max readings. Would be also interested to hear if someone knows of a replaced battery.
2014 BMW i3 REx
2014 BMW i3 BEV - retired

i3lady
Posts: 1
Joined: Sat Feb 23, 2019 9:51 am

Re: Battery Replacement Under Warranty

Sat Feb 23, 2019 10:02 am

This makes me mad. We have a 2015 i3. We were told that our battery capacity would be around 100 with a slight decrease in milage over the years. Its almost 4 years old now, and 4 mos. ago, my battery started charging only up to 50 mph - who the hell in CA can drive a car with 50 miles capacity?!

I have taken it to the dealer 2x and all they do is run it thru their computer diagnostics and as long as the readouts are fine, they say the battery doesn’t need replacing.

Not only does the battery not charge to a meaningful capacity, it goes down very fast.

Does anyone know who I can take this issue to besides the dealer? What are the exact numbers for the warranty? (Meaning what is 70% capacity charging capacity in order to trigger the warranty?)

Thanks!

alohart
Posts: 2022
Joined: Sat Nov 01, 2014 7:36 pm
Location: Honolulu, HI

Re: Battery Replacement Under Warranty

Sat Feb 23, 2019 12:39 pm

i3lady wrote:This makes me mad. We have a 2015 i3. We were told that our battery capacity would be around 100 with a slight decrease in milage over the years. Its almost 4 years old now, and 4 mos. ago, my battery started charging only up to 50 mph - who the hell in CA can drive a car with 50 miles capacity?!
If this is the estimated range, it can be quite inaccurate and affected by driving conditions during the previous 18 miles which might not be the same as the current conditions.
i3lady wrote:Not only does the battery not charge to a meaningful capacity, it goes down very fast.
If this is a change from previous behavior not due to colder weather, the capacity of your battery pack might be low.

You could estimate the usable capacity of your battery pack by driving a significant distance and noting the measured efficiency during that drive that iDrive can display in miles/kWh. Note the charge levels at the start and end of this drive. For example, if the charge level at the start was 90% and at the end was 40%, the charge level dropped 50%. If you drove 32 miles at an efficiency of 4 miles/kWh, your drive consumed 32 miles / 4 miles/kWh = 8 kWh of energy. The total usable battery pack capacity would be 8 kWh / 50% = 16 kWh. The nominal usable capacity of your battery pack when new was 18.8 kWh which is apparently the capacity that BMW uses to determine the capacity degradation percentage. The current percentage of the nominal usable capacity would be 16 kWh / 18.8 kWh = 85%.

Note that this is an estimate because the charge level percentages are calculated values that aren't perfectly accurate. BMW dealers have a more accurate procedure to measure the battery pack capacity that involves discharging the battery pack to a low charge level and then measuring the energy needed to fully charge the battery pack.
i3lady wrote:Does anyone know who I can take this issue to besides the dealer? What are the exact numbers for the warranty? (Meaning what is 70% capacity charging capacity in order to trigger the warranty?)
According to the "Lithium-Ion High Voltage Battery Capacity Coverage" section of the i3's Service and Warranty Manual:
"If an authorized BMW center’s capacity check concludes that the net battery capacity is less than 70 percent of its original nominal value when it was new, this level of capacity loss is considered excessive."

So you'd need to take your i3 to an authorized BMW center which, in the U.S., is a BMW dealer certified to repair i3's.
Aloha,
Art

2014 BMW i3 Arravani Grey, Giga World, Tech + Driving Assist, Parking Assist, DC Fast Charging, JuiceBox EVSE

jadnashuanh
Posts: 4916
Joined: Thu May 22, 2014 2:07 pm
Location: Nashua, NH USA

Re: Battery Replacement Under Warranty

Sat Feb 23, 2019 5:25 pm

Even in warm weather, if you're using your i3 on the freeways at 75-80mph or so, especially if you're climbing grades, your range will be down. The fairly common stop and go on the freeways when you get up to speed and then stop doesn't help, either. Regen helps, but it's never as efficient as what was used to get to speed.

FWIW, prior to the larger batteries that started to show up in 2017, the EPA range was never 100-miles unless, maybe if you babied it in EcoPro+ mode - it was in the low 80's..
Jim DeBruycker
2011 535i x-drive GT, 2014 i3 BEV

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MKH
Gold Member
Posts: 565
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Location: Dallas

Re: Battery Replacement Under Warranty

Tue Feb 26, 2019 3:41 pm

Someone on the i3 Facebook group posted similar battery issues. Found his due to “charge and go” charging at work, not allowing the car enough time on charge to do battery cell balancing. Said after switching to leaving car plugged in overnight at home for charging, range came back after few weeks.
Mark H.
2015 i3 Rex, Capparis White, Tera World, Technology & Driving Assistant, Parking Assistant, Harman Kardon Audio System, 19 inch 427 wheels, EVoInnovate EVSE

jadnashuanh
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Joined: Thu May 22, 2014 2:07 pm
Location: Nashua, NH USA

Re: Battery Replacement Under Warranty

Tue Feb 26, 2019 4:09 pm

Unlike most battery powered devices like say a cellphone or laptop, a smart device like the i3 literally disconnects the power once it determines maximum charge and conditioning has been achieved. IOW, especially since BMW doesn't use the full theoretical capacity of the battery, it doesn't significantly degrade its life if you just let it do its thing by being plugged in. Lesser devices often can and do show degradation when left plugged in for extended time.

FWIW, after the initial charge, at least on mine, it's not all that uncommon for it to turn the EVSE back on for awhile after a delay, probably to rebalance the cells. According to the i3 book, the same amount of 'wear' on the battery occurs from 10 recharges from 90-100% as one recharge from 0-100%. I like having the full charge pretty much whenever I decide to go out and do something. After 4+ years, season-to-season for adjustments, it has essentially the same range.
Jim DeBruycker
2011 535i x-drive GT, 2014 i3 BEV

alohart
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Location: Honolulu, HI

Re: Battery Replacement Under Warranty

Tue Feb 26, 2019 4:49 pm

MKH wrote:Someone on the i3 Facebook group posted similar battery issues. Found his due to “charge and go” charging at work, not allowing the car enough time on charge to do battery cell balancing. Said after switching to leaving car plugged in overnight at home for charging, range came back after few weeks.
It's not necessary to have an EVSE plugged into an i3 for cell balancing to occur. Cell balancing occurs automatically whenever the battery pack charge level is "high enough". A BMW engineer apparently told British i3 owners that 85% is high enough, but I've never found any cell balancing documentation to confirm that.

If the cells' charge levels are significantly different, the charge level of the battery pack could drop enough during cell balancing for charging to commence again if an EVSE is plugged in. The cell balancing speed increases with charge level, so leaving an EVSE plugged in might make cell balancing complete a bit more rapidly, but I doubt that this would be noticeable.

So it's more likely that the situation described on Facebook was due to the i3's battery pack not remaining at a high enough charge level long enough for cell balancing to finish because the driver departed work shortly after charging. When charging occurred overnight at home, the battery pack remained at a high enough charge level for long enough for cell balancing to finish.
Aloha,
Art

2014 BMW i3 Arravani Grey, Giga World, Tech + Driving Assist, Parking Assist, DC Fast Charging, JuiceBox EVSE

rockphone
Posts: 2
Joined: Thu Jan 10, 2019 10:11 am

Re: Battery Replacement Under Warranty

Wed Feb 27, 2019 10:56 am

Google " bmw i3 BC battery check "
You must check the actual amount of battery/energy storage capability for warranty: 18.8 is the starting point, when its in the 13 range before 8 years or 100,000 miles you can demand a free battery. Mileage is NOT warranty related. Hope that helps.
example whatch this: https://www.youtube.com/watch?v=ELT5b2YWL58

alohart
Posts: 2022
Joined: Sat Nov 01, 2014 7:36 pm
Location: Honolulu, HI

Re: Battery Replacement Under Warranty

Wed Feb 27, 2019 2:09 pm

rockphone wrote:You must check the actual amount of battery/energy storage capability for warranty: 18.8 is the starting point, when its in the 13 range before 8 years or 100,000 miles you can demand a free battery.
The Batt. Kapa. max calculated value displayed in the hidden service menu can't be used to determine whether the usable battery pack capacity has dropped below 70% of the nominal new 60 Ah battery pack capacity of 18.8 kWh. The few low Batt. Kapa. max cases that I've read about resulted in a BMW dealer doing something that increased the usable battery pack capacity above 70% of the nominal new capacity without replacing any battery pack modules. Maybe the dealer balanced the battery cells' charge levels, recalibrated the usable battery capacity calculation and/or displayed charge level, or reduced the sizes of the low and/or high charge level buffers any of which would increase the usable capacity.

However, if the battery pack capacity has actually decreased to less than 70% of the nominal new capacity, the warranty does not specify that the battery pack would be replaced. Because the pack contains 8 replaceable modules, restoring the usable capacity to above 70% of the nominal new capacity might be accomplished by replacing one or more modules. It's too early to know for certain.
Aloha,
Art

2014 BMW i3 Arravani Grey, Giga World, Tech + Driving Assist, Parking Assist, DC Fast Charging, JuiceBox EVSE

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