Bmw I3 Long Term Battery Capacity Written Study: Amend Than Expected

The middle of whatsoever electrical vehicle is its battery. This BMW i3 cutaway shows the battery removed from endeavour module. 

When it comes to electric cars, it’sec all well-nigh the battery. Well, it’sec non quite that unproblematic, only given how of import the battery is to the toll, reach inward improver to performance of the vehicle, it’sec pretty unopen.

When mortal is considering purchasing their get-death electrical automobile, they will sure plenty hold a lot of questions.  The 1 research that seems to live on nearly everyone’sec listing is: “How long testament the battery last?”

The problem is, it’sec been really hard to reply that research authoritatively because we exactly haven’t had plenty information.  That’s because modern electric cars that are powered past high-voltage lithium ion battery packs take been on sale for less than 10 years, as good as long term testing results exactly weren’t available.  In fact, the Nissan LEAF was the kickoff high-volume all-electrical automobile brought to marketplace, likewise that model has exclusively been on sale for a niggling over 6 years.

Nissan’2d early LEAF battery woes:

Some of the early on Nissan LEAFs had premature battery degradation issues, especially those that were inward service inwards hot climate areas like Arizona. It became such a job that Nissan changed the chemistry of their batteries inwards 2015 to a more than temperature-tolerant version as well announced an improved battery warranty to tranquillity the concerns of electrical electric current owners likewise futurity buyers. The negative press from this task threatened to prepare back the advancement of all makes of electrical cars, because it brought to calorie-gratis the possibility of EV battery packs failing before than previously predicted.  However, this was a self-inflicted injure, inward my sentiment. Nissan elected to bring the LEAF to marketplace amongst a uncomplicated air-cooled battery pack, instead of employing a sophisticated liquid-based arrangement similar Tesla together with GM were already using dorsum so. The conclusion to do as well in addition to so allowed for a lower MSRP, also as a shorter R&D electric current, only most likely contributed to the early degradation problems that exactly most LEAF owners experienced.

An early Nissan LEAF battery pack

Tesla & GM batteries performing goodness:

Fortunately, the other mass-market place identify EV manufacturers that launched their respective cars earlier inwards the decade option out non had the same battery degradation issues that Nissan experienced. Both the Chevrolet Volt inwards addition to the Tesla Model southward hold complex, liquid-based thermal management systems together with the battery packs of both of these vehicles await to live holding upward rattling good over 4th dimension.

In fact, Plug In America has been collecting information from hundreds of high-mileage Model due southward owners, as well as has built a database of battery degradation rates. They’ve constitute that the average Model due S possessor is experiencing a loss of lonely ii.3 miles of attain for every x,000 miles driven.  Considering all Tesla vehicles offering more than than 200 miles of attain, an estimated loss of exclusively 23 miles of pass for every 100,000 miles of driving is rattling adept. Obviously that the accuse per unit of measurement of 2.3 miles of loss per x,000 testament likely accelerate at around signal, because battery capacity loss isn’t linear, but all of the vehicles in the written report had more than than than 50,000 miles. That made them good candidates to written report the loss of pass over fourth dimension.  General Motors has similarly reported no problems with Volt battery packs experiencing early capacity loss.

 

The happy novel possessor on delivery 24-hr interval, May 21st, 2014.

How’s my BMW i3’2nd battery belongings upward?

BMW launched their start retail all-electrical automobile, the i3 inward Europe inward ho-hum 2013. Here inwards the North America, the offset i3 deliveries started inward May of 2014. I really took delivery of the offset i3 REx inwards the U.S. besides I essay more than than than the average mortal, too so I select 1 of the highest mileage i3s on the route. I’i grand a couple weeks shy of my iii-twelvemonth anniversary alongside the machine in addition to I have got lxx,000 miles on the odometer. I know I’k solely 1 sample, simply if what I’ve experienced turns out to live the norm, as good as in addition to and then i3 owners are going to live rattling happy with how their battery holds upward over quaternary dimension. BMW is i of the few EV manufacturers that offering a clear battery capacity loss warranty, inward improver to has guaranteed at to the lowest plane 70% capacity for 8 years or 100,000 miles. The stated usable capacity for the 2014 i3 is 18.viii kWh. Therefore, the battery would postulate to degrade to xiii.xv kWh to trigger a warranty claim.

Methods used to get inwards at my decision

I’ve institute that l-50 though the accomplish estimator does a pretty practiced chore for daily driving, it’2d not most accurate enough to role for recording as well as documenting the true range of the vehicle. Instead, I select 2 other types of info points that helped grade the footing of my conclusions regarding the electrical current reason of wellness of my battery.

First, I oft tape my trip mileage inwards improver to remaining terra firma of charge before I plug inward. This gives me a more than than accurate idea of how far I tin give-upwards the ghost per accuse than what the range reckoner provides. (Frequently called the GOM or Guess-O-Meter past precisely near EV enthusiasts) The fact that I selection out an i3 amongst range extender complicates it a petty, because the pass on extender turns on when the SOC inward nether 7%. Therefore, I lonely conduct access to 93% of the usable capacity of the battery before the REx fires upwardly.  The simple formula I purpose is arrived at past dividing the number of miles driven past the per centum of battery used. That value testament live how many miles (or what percent of 1 mile) the auto has traveled for every ane% of battery used.  I as well as then call for to multiply that by .93 (100% minus the vii% buffer) together with I as well as and then take how many miles the auto would have been able to acquire if I had continued driving until the REx turned on.

Examples:

Starting SOC: 100%

Ending SOC: 45%

SOC used: 55%

Miles driven: 45

(45/55) x .93 = .76 (76 miles per accuse)

Starting SOC: 92%

Ending SOC: 8%

SOC used: 84%

Miles driven: 67

(67/84) 10 .93 = .74 (74 miles per accuse)

 

The machine is nonetheless estimating 22 miles of electrical give later driving 53 miles. I tin can pretty much even so bank on 72 to 78 miles of attain amongst normal driving inwards Comfort fashion inwards temperatures inwards a higher domicile threescore degrees. 

When using this method to guess battery performance it’2d important to tape the ambient temperature if you alive inwards an surface surface expanse that experiences moderate to extreme common cold together with hot temperatures. These temperature swings will bear upon the automobile’2nd range. The mutual common cold atmospheric status has a much more than dramatic event than hot conditions does, inward addition to it’2d of import to compare the acquaint figures with past times data from the same time of the yr, when temperatures were similar.  For the constituent of this comparison I’yard stating figures that were gathered when the temperatures were between threescore degrees together with 80 degrees, which is or so the optimum operating temperature range for the i3’2d battery. For example inward the coldest months of the yr, with temperatures below 20 degrees, my average electrical attain was as depression every bit exclusively 55 miles per accuse.

The infinitesimal method I used involves the machine’sec onboard diagnostics tool meant for service personnel, called the hidden service card. This offers an jurist of the battery’2nd state of health. The onboard figurer calls it the “Batt.Kapa.Max” also it displays the amount of usable capacity (non total capacity) inward kWh. This number isn’t just accurate – it’sec an approximate, and I caution i3 owners from looking at it as well treating it every chip a precise fact. In monastic order to purpose this gauge to really assist y'all sympathise as good as monitor your battery’s capacity, you lot lot telephone telephone call for to cheque it oftentimes, as well as nautical nautical chart the readings on a graph. The number provided tin tin can swing every flake much every fleck ii kWh upward or downwardly on a daily basis, so it’2nd clearly non precise.

 

The Batt.Kapa.max reading inwards the hidden service neb of fare is averaging virtually xviii.2 kWh after iii years inwards add-on to 70,000 miles. That'sec downwards from nearly xix.ane kWh when the auto was novel

Don’t panic if yous depository financial institution cheque it ane solar solar twenty-four hour period in addition to the reading is unusually depression. What I’ve institute is that to learn a proficient reading yous lot should drain the battery as low as yous tin tin tin, likewise so bank check the reading inwards 1 representative it’s fully recharged. The battery should too live every combat more than than or less 70 degrees Fahrenheit, every flake colder temperature plow over a false reading that is slightly lower than the true value.  BMW has warned against relying on this since it is an approximate. The only mode to perish a truly accurate mensuration (for warranty claims) is to guide a BMW service department perform a exam.

BMW claimed that the usable capacity for the 2014 - 2016 i3s was 18.viii kWh. However, exactly nigh owners hold seen as high every fighting xix.nine kWh available when they’ve checked the Batt.Kapa.Max reading. This tin can either live attributed to an inaccurately high reading (call back this is not a precise reading), or that BMW has really opened upwardly more than than than the eighteen.8 kWh they claim is available. The highest reading I take e'er seen on my automobile was 19.ii kWh, inward addition to the lowest was xvi.1 (inwards the wintertime). When my automobile was novel the average reading inward favorable atmospheric condition was almost xix kWh. Today, my average reading is straight virtually 18.2 kWh. If these average readings are right, it would mean that I’ve lost good-nigh .8 kWh of usable capacity after on 36 months, lxx,000 miles likewise exactly close 1,000 complete charging cycles.  (I’ve probably plugged inward closer to ii,000 times, just my average trip betwixt plugging inward is exclusively close 37 miles).

The .eight kWh loss of usable capacity seems to live inward business concern amongst my recorded attain info.  Since I’m averaging virtually iv mi per kWh, I should live witnessing a loss of almost 3 miles of accomplish, (.viii x iv = 3.2) which is just what my attain readings have got recorded. When the machine was novel, I was averaging 78 miles per accuse inwards favorable conditions conditions status; it’sec straight downwardly to 75 miles per accuse. That’sec pretty impressive since the EPA pass on rating for the 2014 i3 REx was 72 miles per accuse. So I’m yet averaging more than than the EPA turn over afterward iii years as good as seventy,000 miles.  Since both measuring methods equate to nigh a 4% capacity loss, I’M pretty confident that they validate each other. Therefore, the 4% is correct, or at to the lowest grade existent close to the actual capacity loss

With careful driving, I tin tin all the same popular off more than than lxxx miles per accuse. On this recent trip I was able to become 84 miles without the reach extender turning on. In social club to conk 80 miles I require to choke along my consumption to v miles per kilowatt hr or meliorate. 

This should live very encouraging for existing i3 owners, as good as assist to alleviate whatever anxiety that those currently considering the purchase of an i3 mightiness lead. I take to believe that the sophisticated thermal management organisation that BMW used inward the i3 is partially responsible for the fantabulous long-term operation of the Samsung battery cells used inward the automobile. If my feel holds true for the mass of the i3 fleet, this is good discussion non solely for BMW, simply as goodness for the entire EV industry. Battery capacity loss concerns are on the minds of many potential consumers that are interested inward entering into the earth of electrical cars. Continued positive reports on battery life testament assistance to alleviate those worries as good as turn over the entire industry a boost of confidence.

However, every chip I said to a higher place my experience is only i info indicate, at that place’s a lot more than than information needed before we know conclusively how long these packs will concluding, but this indeed existent encouraging. Based on my personal findings, I suspect that BMW won’t have to worry almost paying out likewise many battery capacity-loss warranty claims.

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