As anyone driven a US spec REx equipped i3 yet?

[jelloslug]

Well?

 

[drb]

If you will look up Inside Ev's on the internet, you will find a good account by Tom of his first journey in his REx. Also, if you will check Tom's blog, bmwi3blogspot, I think you will find other good accounts of driving with the REx.

 

[Devin]

I have a REx that is currently in production and hopefully will be here in a few weeks. I'm really curious to hear from anyone who has tried a road trip at highway speeds that involved more than just a few mile using the REx. Anyone out there?
Devin solar orange REx hopefully in July 14

 

[TomMoloughney]

Well?

As mentioned by drb here are a few pieces that I have done on the REx"

http://www.greencarreports.com/news/1092291_2014-bmw-i3-rex-range-extended-electric-car-drive-report-by-very-first-owner

http://www.plugincars.com/8-key-questions-about-bmw-i3-electric-car-129816.html

http://bmwi3.blogspot.com/2014/05/first-i3-rex-road-trip-hotels-bmw.html

 

[Devin]

Thanks Tom, I'm expecting an REx in a few weeks. Several times per year I'll need to drive a few hundred miles over flat-as-a-pancake Illinois farmland, hopefully at about 70 miles per hour. It sounds like I'll be able to do it without too much trouble as long as I stop for gas every hour or so. Which, by the way, I see the hourly stops as only a slight inconvenience but really not that big of a deal. I figure it will add only about 5 minutes to each hour of driving.
Devin solar orange REx, hopefully in July

 

[CompuMagic]

I have the i3 REx US edition - since May 28th... I got it off the dealer floor (I knew it was coming and the dealer had ordered it for themselves, not me, and at one point they let me put a down payment on it and then I backed out a few months later due to current vehicle situation). As it turns out, I got it anyway because the current vehicle started to have issues again. I was under the impression the one coming to the dealer was the Tera version but when I saw it, it was the Giga but all options applied except the larger tires. Turns out I really like the giga more than the tera. More detail about a long trip I took in it here:

http://www.mybmwi3.com/forum/viewtopic.php?f=10&t=1074

It is an amazing vehicle to be sure. If they can double the battery capacity in the next few years and lower the price I think it could really be a mass market vehicle and I think that is where they are headed. I look forward to the i5 or an SUV version with larger capacity battery and the same carbon fiber plastic.

 

[Devin]

Thanks, I'm impressed at your range on electric. But what I'm really curious about is how the REx car responds on a road trip. I understand that BMW wants everyone to know that it's a city car and not intended for cross country travel. And I also understand that it really isn't capable of climbing a mountain when the battery is dead using just the REx. But what about a trip of a few hundred miles down the highway on relatively flat land? which seems like a relatively common scenario for many people. 99% of the time I just drive around in town, but a few times per year we want to visit grandma in a different city. Will it work??
Devin

 

[MikeS]

Thanks, I'm impressed at your range on electric. But what I'm really curious about is how the REx car responds on a road trip. I understand that BMW wants everyone to know that it's a city car and not intended for cross country travel. And I also understand that it really isn't capable of climbing a mountain when the battery is dead using just the REx. But what about a trip of a few hundred miles down the highway on relatively flat land? which seems like a relatively common scenario for many people. 99% of the time I just drive around in town, but a few times per year we want to visit grandma in a different city. Will it work??
Devin

Just search the forum as there are a few threads that mention long journeys.

 

[fdl1409]

Of course it will work. Some time ago somebody reported in the German i3 forum about a 900km trip in a single day. Just keep filling it up, no problem whatsoever.

Frank

 

[CompuMagic]

From the manual page 152:

It bothers me that in the USA California dictates for the rest of the nation that we cannot manually turn on our range extender gas generators if we anticipate a long trip, while the battery is at a high level, and that we must wait until the battery is down to 6.5% for the REx to kick in automatically... That flies in the face of the second paragraph above.

I am not quite sure how to interpret the first paragraph under "Range" and I hope it does not mean the battery will "appreciable deteriorate"... I will be investigating that to make sure what it means.

 

[fdl1409]

The battery won`t deteriorate, but you might feel a little less power, because voltage is highest at 100% SOC and will be reduced as SOC declines. You will only feel this if you drive with maximum power.

Haven`t used my REx yet, but I will not start it any earlier than 6.5% SOC. I believe you all worry too much over there.

Frank

 

[Gonville]

I am not quite sure how to interpret the first paragraph under "Range" and I hope it does not mean the battery will "appreciable deteriorate"... I will be investigating that to make sure what it means.

I think it means the performance of the "electric drive" not the "battery". Indeed that is exactly what it says.

As our US colleagues have discovered if you drive at 80mph on the freeway with AC on and in Comfort mode, and drive 15-20 after Rex comes in , up a hill, it will slow down(!) "appreciably". Pity the sales rep didn't read the manual.

(So I think they have covered themselves on the safety front. )

 

[i3burlington]

Discharging the battery to a level as low as 6% will quickly cause deterioration of the battery
Not that you will see immediately but it will drastically shorten the battery life

Many articles are about explaining the discharge vs life of the battery but in very general terms, the more you discharge per cycle, the shorter the battery life

This is a serious mistake by BMW NA

 

[Buskraut]

Keep in mind 6% of remaining capacity is not really 6% of total battery capacity. For reliability of the pack BMW engineers only allow us to use 18.8 out of 21.6kWhrs. That means there is a 13% "buffer", some of which is allocated at the low end and some at the upper end of the SOC. All lithium battery management systems are designed this way. Obviously BMW felt this was the optimal cycle range for their NCM cell chemistry.

In other words, for long term pack reliability reasons, BMW won't let you charge it all the way up or fully deplete it.

 

[MikeS]

Discharging the battery to a level as low as 6% will quickly cause deterioration of the battery
Not that you will see immediately but it will drastically shorten the battery life

Many articles are about explaining the discharge vs life of the battery but in very general terms, the more you discharge per cycle, the shorter the battery life

This is a serious mistake by BMW NA

Better you get a clearer understanding of the machine before you make such incorrect statements. BMW have built in the necessary buffer.

 

[TomMoloughney]

Discharging the battery to a level as low as 6% will quickly cause deterioration of the battery
Not that you will see immediately but it will drastically shorten the battery life

Many articles are about explaining the discharge vs life of the battery but in very general terms, the more you discharge per cycle, the shorter the battery life

This is a serious mistake by BMW NA

Better you get a clearer understanding of the machine before you make such incorrect statements. BMW have built in the necessary buffer.

Exactly. Anyone reading this should know there absolutely is no concern for running the car down to the 6% REx threshold. Do not worry about this at all.

The 6% threshold is of the usable capacity, not the packs overall capacity. There is a buffer already there for safety purposes and to prevent deep discharge damage. So when the REx turns on the battery is probably really at around 12% to 15% of it's full capacity.

I've driven over 140,000 electric miles in BMW's e-mobility pilot program and purposely ran my cars till they just about stopped moving dozens of times and probably plugged in with the usable SOC less than 5% sixty or seventy times. The capacity loss I experienced was about what I would expect it would be even with being cautious about deep discharges, which was about 3% to 3.5% every 15,000 miles and was no more than what the others were reporting that didn't do such deep discharges.

Personally I wouldn't even consider worrying about the 6% SOC activation point of the i3 REx unless perhaps you would be driving so many miles that you'd be activating it every single day. Even then unless you lived in a very hot region where the battery temperatures would always be at elevated levels you probably would have very little noticeable advanced degradation compared to another car that didn't get driven to the 6% low limit often.

It's actually much worse if you fully charge the car to 100% and let it sit for long periods of time without use (weeks).

 

[CompuMagic]

Keep in mind 6% of remaining capacity is not really 6% of total battery capacity. For reliability of the pack BMW engineers only allow us to use 18.8 out of 21.6kWhrs. That means there is a 13% "buffer", some of which is allocated at the low end and some at the upper end of the SOC. All lithium battery management systems are designed this way. Obviously BMW felt this was the optimal cycle range for their NCM cell chemistry.

In other words, for long term pack reliability reasons, BMW won't let you charge it all the way up or fully deplete it.

That sounds reasonable. It will be interesting to see how the batteries last. I know recharging Lithium Ion batteries is complex.
I got one of the first Ford Escape Hybrid SUVs back in October 2004 and have been quite surprised how well this Nickel Metal Hydride Battery (NiMH) battery has performed. I still have the vehicle, with some recent rust repair and issues caused by someone who rear ended me. I still can milked that battery and drive on it alone up to 30mph, or in low gear up to 40, for short lengths. And I can still get the advertised 31-36MPG like I was able to do when I first got the car. You just have to follow the speed limits and be easy on the pedal. I just hope the i3 Lithium lasts and performs as well at the NiHH in my Escape, but I understand it is a completely different battery technology today.

 

[Gonville]

Discharging the battery to a level as low as 6% will quickly cause deterioration of the battery
Not that you will see immediately but it will drastically shorten the battery life

This is not correct for the i3. See Tom's post.