i3 with 57kWh battery

[i3daytonoh]

https://www.bmwblog.com/2018/12/13/bmws-research-project-fastcharge-launches-450kw-prototype-station/

 

[TheMK]

One day I hope to be able to drop the battery pack from my car, upgrade the capacity, and have a new, longer range EV. None of the upcoming EVs seem to really interest me much, or are just too out of my budget. The i3 is kind of unique with it's carbon fiber structure, RWD (appealing to me, though others would be happy enough with FWD), and great chassis dynamics. Between a large battery pack, and the REx engine you could go as far as people in Tesla 100Ds do today. The build quality of the i3 gives me confidence that as long as I keep up on preventative maintenance, I should be able to go many miles in this car.

 

[Anonymous]

ME TOO!
And I feel exactly the same as you do about the "unique" i3.

BMW is certainly considering battery-pack upgrades for the US market - hopefully if implemented, the projected price will drop.

https://cleantechnica.com/2017/07/02/bmw-i3-94-ah-33-kwh-battery-upgrade-hits-us-market/

I know that for my daughter-in-law's Prius, originally a battery-pack replacement was in the neighborhood of $4,000 to $5,000, and they can now be had for $1,500.

According to a company that did a complete component-by-component tear-down of an i3, the battery pack, though an integral part of the car's structure - is designed for easy removal for maintenance. It is also designed so that individual cells can be removed and replaced.

https://youtu.be/YZ9UpLkVJlo

 

[alohart]

According to a company that did a complete component-by-component tear-down of an i3, the battery pack, though an integral part of the car's structure - is designed for easy removal for maintenance. It is also designed so that individual cells can be removed and replaced.

I believe that individual cells aren't designed to be replaced, but the 8 12-cell modules are designed for easy replacement.

 

[jadnashuanh]

When BMW has optioned bigger (heavier) battery packs, they also have changed the springs in the rear (and maybe the shocks). So, to do things right, you'd need to swap both the battery modules and the springs, and reprogram the computer to recognize the larger capacity. That would also probably call for a four-wheel alignment.

It would be nice if the on-board charging could also be upgraded to keep the charging time down, but many people can live with overnight and don't need a full charge to go back out again after work until morning.

Germany just commissioned a CCS unit that can handle up to 450Kw (at nearly 1000VDC)! Nobody makes a car that can utilize it at its maximum, but it proves it's possible to charge an EV fast if it's designed for it.

 

[Anonymous]

When BMW has optioned bigger (heavier) battery packs, they also have changed the springs in the rear

From the EU BMW blog:
These new battery cells are physically the same size as the currently used cells, but can hold 50% more energy and are only slightly heavier.

Not much out their on what exactly is done as part of the retrofit - but they do have the program rolled out in some parts of Europe. Would be interesting to know what all is involved in the "swap". According to the blog, the i3 battery system and tray were specifically designed for future upgrading. Would be nice to see BMW follow through with that, making it both end-user easy, and not too expensive to be practical.

 

[jadnashuanh]

The weight increase was stated in some earlier press releases, and was evident if you compared the weight reported on the vehicles before and after the new, higher capacity batteries were available. Being the same size does not mean they were the same weight.

 

[i3Houston]

Its disappointing BMW has not offered it yet, lot of folks would have been happy to upgrade for the longer range.

Now that it has cooled down here in Houston, i3 range has dropped to 50ish miles; bigger battery would be a really nice.


Maybe i3 REX can take the extra weight, should owners decide to get rid of it?

 

[jadnashuanh]

The REx uses different springs/shocks in the rear versus the BEV, but you'll probably find they also vary by year when the battery pack got heavier. Otherwise, the car would not sit level or have the same dynamic balance. There's also a limit on how much the headlights can adjust automatically.

 

[Anonymous]

Finally found a good comparison article. According to the tester - the new higher capacity battery pack adds 170 lbs to the curb-weight of the i3. Wonder if BMW addresses that in their battery-swap upgrade - and includes suspension tuning? Or if they consider it within operational limits of the existing suspension? (Or they leave it up to the owner to "correct"). At least there are several after-market companies making sport-tuned suspension upgrades and lowering kits for the i3, and are pretty budget-friendly.

 

[i3Houston]

Only 170lbs! Would that really affect handling.

Driving with passengers in back seat ((350lbs) should affect more, would not it?

 

[gps1539]

Only 170lbs! Would that really affect handling.

Driving with passengers in back seat ((350lbs) should affect more, would not it?

but it would be an additional 170 lbs i.e. passengers + extra 170lbs, so it could effect handling (and braking).

 

[Anonymous]

but it would be an additional 170 lbs i.e. passengers + extra 170lbs, so it could effect handling (and braking).

Yeah, guess it would all depend on what max specs the existing suspension/brakes were engineered for. Automotive engineering design usually is based a safety factor of 3, with components engineered to support three times their maximum design load before failure..

I can see the change in suspension between Bev and Rex, as the Rex engine, adds 265 lbs to the car. 170 lbs for the upgraded battery could be within engineered operational tolerances for the maximum design load for the suspension and brakes.

 

[i3Houston]

I see, feel difference might not be noticeable in day to day driving!

Maybe someone will retrofit tesla 3 battery before bmw offers battery upgrade!

Personally I bought bmw i3 over Nissan leaf just because bmw i3 battery can be upgraded!

 

[i3Houston]

but it would be an additional 170 lbs i.e. passengers + extra 170lbs, so it could effect handling (and braking).

Yeah, guess it would all depend on what max specs the existing suspension/brakes were engineered for. Automotive engineering design usually is based a safety factor of 3, with components engineered to support three times their maximum design load before failure..

I can see the change in suspension between Bev and Rex, as the Rex engine, adds 265 lbs to the car. 170 lbs for the upgraded battery could be within engineered operational tolerances for the maximum design load for the suspension and brakes.

Well no need to replace full battery pack but maybe like model 3 mid range(battery pack with just 25%fewer cells or modules) , that way weight stays the same but the range goes up.

 

[Anonymous]

One interesting note: Apparently the new BMW i3 battery upgrade program rolled out in Europe is only available for i3 BEV models. A UK i3 owner ordered the upgrade from BMW through his dealer, and then the installation was cancelled because he had the Rex model, BMW would not do the upgrade, as was for BEV's only. The owner was not sure if the reason was technical, or regulatory.

 

[alohart]

Well no need to replace full battery pack but maybe like model 3 mid range(battery pack with just 25%fewer cells or modules) , that way weight stays the same but the range goes up.

A Tesla battery pack contains thousands of small battery cells unlike an i3's battery pack that contains only 96 large battery cells connected in series. If 25% of an i3's cells were eliminated, the output voltage of the pack would drop by 25% which would not work with the motor and charging electronics.

Some have suggested that the space used by the REx engine could hold additional battery cells, but this would not work because the output voltage would be too high. BMW's choice to use large-format battery cells in a single series-connected string simplifies pack construction and likely minimizes cost but eliminates the possibility of increasing or decreasing battery pack capacity by merely adding or removing cells. Instead, we have seen the capacity of an i3's battery pack increase only when higher capacity battery cells of the identical dimensions have become available (e.g., 60 Ah -> 94 Ah -> 120 Ah).

Tesla battery packs conceptually contain strings of 96 series-connected battery cells like an i3 but with the multiple strings connected in parallel, so the output voltage is similar to an i3's battery pack. To vary the battery pack capacity, Tesla needs only to add or remove some of the 96-cell strings. Doing so maintains the same output voltage which the motor and charging electronics require. A battery pack containing thousands of small cells certainly makes pack construction more complex and likely more expensive, but it does allow packs of various capacities to be built using the same battery cells.

 

[alohart]

According to the blog, the i3 battery system and tray were specifically designed for future upgrading.

I've read that the modular battery pack was designed for the easy replacement of only those battery modules that have degraded, not to facilitate easy upgrades. If upgrades were planned, BMW would likely not be so reluctant to offer them.

 

[alohart]

Finally found a good comparison article.

Please post a link to this article. I am very interested in learning how much weight each battery pack upgrade added.

According to the tester - the new higher capacity battery pack adds 170 lbs to the curb-weight of the i3.

Is that relative to the 60 Ah model or the 94 Ah model? I had read that the 94 Ah battery pack was only ~50 kg (110 lb) heavier than the 60 Ah battery pack yet increased capacity by 57%. If the 120 Ah battery pack is really 77 kg (170 lb) heavier than the 94 Ah battery pack, that's disappointing because its capacity is only 28% greater.

 

[Anonymous]

Please post a link to this article

Here you go....

https://cleantechnica.com/2016/09/19/comparing-2014-bmw-i3-rex-60ah-vs-2017-i3-rex-94ah/

Is that relative to the 60 Ah model or the 94 Ah model?

The article compared the 2014 BMW i3 REx (60Ah) to the 2017 i3 REx (94Ah)