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Joined: Fri Nov 16, 2018 2:47 pm

Battery capacity issue

Fri Nov 16, 2018 2:59 pm


I have an issue with my 2014 BMW i3. Battery capacity shows about 40-45 miles when charged at 100%. At 70% charge it shows 27-29 miles range. To my understanding this is way under the 70% capacity to be considered excessive under warranty.

These numbers are in the summer and gets worst in winter.

I have taken it in for service to 2 different BMW dealers about 6 times and they always say they follow all tests BMW tells them to do and find the battery under normal capacity. I feel like they are pushing back to not honor the warranty and I’m not sure what else to do.

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Joined: Thu Jul 12, 2018 2:30 pm

Re: Battery capacity issue

Fri Nov 16, 2018 3:16 pm

Try a different dealership.
Send results to BMW directly.
Check Battery Kappa under service menu.

I have 2015 i3, the lowest range guesso-meter has shown is ~50 miles and that was due to driving to fast/hard. So if you dont live up on hill top and dont drive too fast up there, then the battery is definitely appears to be at half of its original capacity.
TM3 Reservation holder/ 2015 i3 Rex

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Joined: Sat Nov 07, 2015 7:31 pm
Location: Baltimore

Re: Battery capacity issue

Fri Nov 16, 2018 8:54 pm

Ask the dealer for the detailed test results and post them here.

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Joined: Fri Nov 02, 2018 5:48 am
Location: Dallas

Re: Battery capacity issue

Sat Nov 17, 2018 5:27 am

Is the range shown in the "guess-o-meter" accurate to actual driving? - If you are fully charged, set your trip-counter, and compare it to the guess-o-meter range - a difference would point to a software issue. If actual and guess'd range are spot-on, then a hardware issue.

Since you have already tried several times through BMW Dealers, do a search for "BMW Customer Service", and contact them directly with this - certainly not normal at all, unless you are driving the car like you are running the Indy 500 - if you drive it like it's a race-car, the guess-o-meter will show that, and drop your range accordingly. You can easily knock 30% or more off of your range by "spirited" driving, just like doing so in an ICE car will reduce gas mileage significantly.

My car made a 50 mile trip from the Auto Auction lot to the Dealership, before I picked it up. When I started driving it, the guess-o-meter range increased over 20 miles - likely because the Dealership driver "drove it like he stole it" on the way back from the auction lot and that was what the guess-o-meter was calculating range from.
Mark H.
2015 i3 Rex, Capparis White, Tera World, Technology & Driving Assistant, Parking Assistant, Harman Kardon Audio System, 20 inch wheels, EVoInnovate EVSE

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Joined: Fri Nov 16, 2018 2:47 pm

Re: Battery capacity issue

Sat Nov 17, 2018 8:29 am

I constantly get this low range in the guess o meter with normal driving and it matches the miles in the trip meter. I definitely think it’s a hardware issue.

I will post the dealership test results here once I get them.

Thank you for the replies!

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Joined: Thu Dec 20, 2018 10:14 pm

Re: Battery capacity issue

Thu Dec 20, 2018 10:21 pm


Any update? I noticed a similar thing on my 2016 with about 22k miles, showing about 50 miles on battery and 41 on gas, nearly a full tank of gas.


Posts: 28
Joined: Thu Dec 20, 2018 10:14 pm

Re: Battery capacity issue

Mon Dec 24, 2018 3:51 am

Just checked the battery capacity in the hidden menu and looks like my batteries are holding up pretty well, 17.5kwh, 2016 with 20k miles.

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

Re: Battery capacity issue

Mon Dec 24, 2018 8:51 am

You don't mention where geographically you're located and the ambient temperature. The temperature of the batteries will have a huge impact, more so on the REx verses the BEV when it's cold out. If you set a departure time while plugged in, you'll warm the batteries and should probably precondition the cabin to maximize your ultimate range. But, when it's particularly cold out, you can be spending a significant portion of your available energy heating things up versus actually moving the vehicle. Worst case would probably be a bunch of short trips where the car has an opportunity to cool to ambient each time. It will then be using lots of energy rewarming the cabin and this can be worse if you need to use the defrosters for both the front and rear. The REx relies entirely on resistance heating, so one watt of heat uses one watt of battery. The BEV's heat pump multiplies that by maybe in the order of 1W of battery transfers 3W of heat, so can be much more efficient, but only when the temperature isn't truly frigid, then it reverts to the resistance heaters. Those may get activated initially when it's really cold in both vehicles.

Last, keep in mind that the estimated range is based on about the last 18-miles of travel. IF that was a cold start and lots of heating, your mileage to empty could be quite short. That estimate could easily be wrong if the next trip was done with setting a departure time with preconditioning of the cabin and it was one continuous trip verses lots of shorter ones. All in all, that is similar to an ICE...lots of cold starts where the vehicle uses more fuel so the engine will run smooth during warmup will wreck havoc on your ultimate mileage versus a longer trip after fully warming up. At least on an ICE, the heating is a waste product so that's not an issue.
Jim DeBruycker
2011 535i x-drive GT, 2014 i3 BEV

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Joined: Sat Jul 21, 2018 8:54 pm

Re: Battery capacity issue

Tue Dec 25, 2018 3:01 am

Atv wrote:Just checked the battery capacity in the hidden menu and looks like my batteries are holding up pretty well, 17.5kwh, 2016 with 20k miles.
2015 REx with ~16k miles, 17.9 kWh through the hidden menu for me.

And for those who don't know how to get to the hidden menu:

Note that when it's colder out, it will read lower (because the battery's capacity is lower when it's cold.) It was 5°C when I did my reading. So if it's currently cold where you are (below ~10°C / 50°F) don't trust that the reading you take right now is "the definitive reading." Take readings every couple months, in different temperatures.

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Joined: Fri Jan 25, 2019 9:41 am

Re: Battery capacity issue

Fri Jan 25, 2019 9:56 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.

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