Why would anyone get the REx in the US?

[ultraturtle]

Why would anyone not get the REx in the US?

I forgot one of the most important reasons:

8. Certified morons like myself occasionally forget to plug the car in at night. A REx would get me to work the next day with no issues, whereas doing the same with a BEV would cost me over $150 in cab fare.

 

[Surge]

Well that's great then.

We now just need the ability to turn it on/off manually in the US. And I'd love to know what the Canadian cars will ship with in this regard…

 

[ultraturtle]

Well that's great then.

We now just need the ability to turn it on/off manually in the US. And I'd love to know what the Canadian cars will ship with in this regard…

I'm 99% certain that USA owners will have the capability to quickly and easily enable this feature shortly after the RExs get here.

 

[Stevei3]

Steve, maybe this is what you meant. It's a battery pre-heat but not a cabin pre-heat:

Feature ZWT - Winter Package
[available with and without REx]
- 494 heated front seats
- ZHV Pre-heating of HV battery with active air flap control: pre-heating the the HV battery ensures that the battery is operating at the optimal temperature which further improves the range and performance of the battery. Additional active control of air flaps to assist in achieving optimum operating temperature.

Hi Surge,

I ment that as well. I was making the point that there is no difference between BEV and REx bar the possibilty to have the heat pump fitted. The description of the heat pump system in English is, as it was in the Dutch information, a very crude translation from the original German text, which was ambiguous to start with. I called the i-Geniuses about it, they had no clear answer. Let's just say, in the end and to my relief, that our REx (indeed with option 494/ZHV fitted) preheats battery and interior just fine.

Regards, Steven

 

[Surge]

I am gradually warming up to the REx :mrgreen:

If you even want to have the option of driving the car on longer distances (150 km+), you need the REx. So for an extra $4000, the i3 goes from a city only car to a year-round, go everywhere car.
Yes, you lose some efficiency and acceleration in the process; but at least for the latter, it was never meant to be a sports car.

My assumptions on range are as follows ** please correct me if you have the i3 REx already **

- highway driving at 120 kph (75 mph)
- flat terrain
- outside temp 0 C (32 F)
- range on REx alone is: 100 km (62 mph)
- range on batt alone is: 100 km (62 mph)

Is this accurate?

 

[ultraturtle]

As a 2nd car for trips <100 miles, it's the BEV and that's perfect.

A decision to purchase a BEV would best be based on the minimum range requirement considering the worst case scenario, which would be the coldest temperature on the last day of either ownership or battery replacement. In my case the assumption that an initial range capacity of 75 miles at 60% highway speeds in fair temperatures will deteriorate to a level greater than the 58 mile range I need 10 years, and 100,000 miles down the road at 25 degrees F might logically drive me toward purchasing a BEV if I believed that temperature, mileage, and time erosion of that capacity to be less than 22%, but the 8 factors I listed made the decision to go with the REx an easy one.

Mind you, I am passing up the opportunity for a $5,000 state income tax credit by opting for the REx. That makes the REx an $8,850 option, but still worth every penny.

 

[fdl1409]

I agree with everything ultraturtle wrote. That is exactly why I ordered the REx. I previously had a Mitsubishi i-MiEV. Kept my Audi A2 Diesel as a long distance and emergency backup. Now the REx makes it possible to sell the second car.

Some more arguments pro REx:

- in the long term battery range will deteriorate. That is something a lot of people worry about. Doesn`t matter much with a REx if after 10 years battery range goes down from 80 to 60 miles. Without the REx, you are more likely to buy a new battery pack. Also easier to sell to a new owner.
- in many cases ( like mine ) the REx replaces a second car.

In the 15 months I had my i-MiEV I would have used the REx only twice for some 20-30 miles beyond the electric range. Still it is absolutely important to have the extra range. There may be emergencies like relatives having an accident and things like that. It would be most unpleasant if an empty battery stops you in such events.

We have had a number of reports in Europe from REx owners driving long distances up to 600 miles in one day. While this should not be the preferred mode of operation for an electric car, this is definitely possible with the REx. Somebody reported 900km from Austria to Sardinia. Started the REx at 75% and arrived on the ferry to Sardinia with 75% battery charge. So the REx was able to hold SOC on that long motorway trip.

Frank
Germany

 

[Plug]

Good post Frank. Those two points you made were important in my decision to go for the REx along with it allowing me to avoid having to rely on public charging for the longer journeys.

 

[Surge]

Yes, good post Frank, but again, long distance driving on REx REQUIRES that we can turn on REx at any SOC.
I am not that optimistic that in the US we'll be able to do this... I'll be holding off my order until this is cleared up. Or until I hear that Canadian cars have the feature.

Why has BMW officially decided to not include this feature on US cars again?

 

[ultraturtle]

Why has BMW officially decided to not include this feature on US cars again?

It is solely to meet CARB BEVx criteria, meaning the REx can claim credit as a pure EV, allowing BMW to sell more high performance vehicles in California.

CARB produced a well thought out document thoroughly explaining their reasoning for the limitations. Basically, they wanted to ensure that a BEVx compliant vehicle will be driven almost completely on electricity, using the gasoline engine strictly as a backup energy source: http://www.arb.ca.gov/regact/2012/zev2012/zevfsor.pdf

I would be very surprised to see any such limitation on a Canadian i3 REx.

 

[Surge]

After having warmed up to getting the REx in my i3, I'm now going to go without it.
Why?
I simply don't need it.
Look- the 100-120 miles per day range of the non-REx (don't forget, more than the REx by about 20% (less weight and more of the battery can be used) -- that's plenty for me.
The REx adds less than 100 miles, and for highway driving more like 50 miles of range (at 75mph). That doesn't do much for me.
If I exceed 100 miles per day, I would be driving 500 miles. Can't do that with the REx unless you want to refuel every 45-60 minutes.

And on top of that I save $4000 and get a faster car.

I'm not saying the REx isn't useful - it is - if your driving range requires it.

And the 'piece of mind' argument is not relevant for me.
I don't carry a second iPhone charger around with me every day, just in case the battery dies.

The i3 non-REx will require more planning for sure, and can't be an only car. But that's fine with me, and that's how BMW designed it anyway.

 

[BrianStanier]

The real world ranges reported so far suggest that you will have to be really really gentle driver to exceed 100 miles! 80 is more like it.

 

[mindmachine]

After having warmed up to getting the REx in my i3, I'm now going to go without it.
Why?
I simply don't need it.
Look- the 100-120 miles per day range of the non-REx (don't forget, more than the REx by about 20% (less weight and more of the battery can be used) -- that's plenty for me.
The REx adds less than 100 miles, and for highway driving more like 50 miles of range (at 75mph). That doesn't do much for me.
If I exceed 100 miles per day, I would be driving 500 miles. Can't do that with the REx unless you want to refuel every 45-60 minutes.

And on top of that I save $4000 and get a faster car.

I'm not saying the REx isn't useful - it is - if your driving range requires it.

And the 'piece of mind' argument is not relevant for me.
I don't carry a second iPhone charger around with me every day, just in case the battery dies.

The i3 non-REx will require more planning for sure, and can't be an only car. But that's fine with me, and that's how BMW designed it anyway.

Hay pal I was beginning to think you you saw the light, you as an engineer should know you are not going to get 100 to 120 miles range in Toronto in the winter. I suspect 60 to 80 miles even on the BEV. Not going to argue with you as I value you as a friend now. The Rex essentially doubles your range winter or summer, faster car really not important,ok. nuf said. :mrgreen:

 

[ultraturtle]

Also note that the ICE gen-set warms to the same temperature in the winter as in the summer, giving essentially the same performance and range, whereas the battery capacity drops severely in the cold. Check out some of the earlier winter posts from our friends in Northern Europe.

Also the battery capacity will degrade significantly with time and use. Again, not so much with the REx system.

Once again, base your decision on the minimum range required and whether or not the BEV can handle it on the coldest day 10 years, 100,000 miles from now.

 

[Surge]

I know, your points are well put, and taken!

A couple of other things I noted:
- 100 km (60 miles) is really all the range I need in a day; this is also the range in winter according to N. European owners
- going to go with a 4 year lease, as opposed to a 10 year commitment… so I'm no longer concerned about battery degradation over time

Note that according to this post from Norway (http://bmwi3owner.com/2014/02/winter/#comment-516), the heat pump improves efficiency by about 4-8% (or 30%, not exactly sure how he calculated it). Then the weight reduction of 10%, and finally you can use the 6% of the battery (the point when the REx comes on automatically in US/Canadian cars).

So given my range, and the other points, no-REx is my preference.

But we are definitely friends and do hope we can meet up one day… (although I'll need to rent that battery trailer!).

 

[mindmachine]

I know, your points are well put, and taken!

A couple of other things I noted:
- 100 km (60 miles) is really all the range I need in a day; this is also the range in winter according to N. European owners
- going to go with a 4 year lease, as opposed to a 10 year commitment… so I'm no longer concerned about battery degradation over time

Note that according to this post from Norway (http://bmwi3owner.com/2014/02/winter/#comment-516), the heat pump improves efficiency by about 4-8% (or 30%, not exactly sure how he calculated it). Then the weight reduction of 10%, and finally you can use the 6% of the battery (the point when the REx comes on automatically in US/Canadian cars).

So given my range, and the other points, no-REx is my preference.

But we are definitely friends and do hope we can meet up one day… (although I'll need to rent that battery trailer!).

Sounds good, can't wait to see you with the battery trailer range extender. Even with the Rex, depending on how it works, I would consider some longer trips I would like to make using the trailer. That's a cool looking unit. If BMW gets it's act together
I could see them renting it to customers.

Also I think your lease choice is a good one. Batteries are going to continue to improve and I believe the rate of improvement will pick up in speed as more EV's are sold.

 

[Surge]

Thanks. Can't wait to become an i3 owner!
Looks like a classic over-engineered German piece of engineering!

 

[Surge]

A couple of you will laugh, but I'm reconsidering the REx again

Reason - cold weather range. It's lower than I suspected. A Nordic owner posted that range may only be ~40 miles on the highway (75mph) in -20C weather (-14F).

I need at least 60 miles of range in all weather conditions, so this means REx, as much as I don't want it, it's a necessity if you live in cold climates and need more than ~40 miles on the highway.

 

[mindmachine]

A couple of you will laugh, but I'm reconsidering the REx again

Reason - cold weather range. It's lower than I suspected. A Nordic owner posted that range may only be ~40 miles on the highway (75mph) in -20C weather (-14F).

I need at least 60 miles of range in all weather conditions, so this means REx, as much as I don't want it, it's a necessity if you live in cold climates and need more than ~40 miles on the highway.

Well I think you will wish you had if you don't and I don't think you will wish you had not if you do.....Enough said.

My years have taught me to error on the side of caution or conservatism.

 

[Surge]

Here's the big problem with the REx - at least in my case, I realized I'm only going to need it when driving on the highway.
When do I drive more than 80 miles in the city in a day?? Never.

And it's on the highway that the REx reportedly doesn't do very well. I'm referencing the Telegraph UK article:
"I thrummed along at 70mph, but it soon became clear that at this kind of speed our comfortable range between fill-ups was more like 40-50 miles."

It's not an option for me to drive below 70 mph - and I think doing so, at least here in the north-east, or west coast, is dangerous. No one really drives 55 mph! So cruising at 70-80 mph is the norm that the i3 needs to maintain.

At this speed, and then adding cold weather (0F) - which by others' estimates will reduce range by over 50% - you are looking at 20 (winter) - 50 miles of highway range on the REx.

So if you need to drive 70-80 mph on the highway, you're not going to get more than 20-50 miles on the REx tank. You'll need to fill-up - at best - every 30 minutes!

So that's a real bummer…. And compounding this, for US/Canada, the REx only comes on when SOC is 6%. So here's what the Telegraph article said about that:
"...but once the charge runs down to five or six per cent and the range extender cuts in, if you keep driving at 75-80mph it can’t maintain the charge.”

So now you must reduce speed below avg highway cruising speed…

Putting this all together, if you're in the US/Canada, the REx will give you +40-50 highway miles, if you drive < 75mph… and maybe not uphill.

To me, it's just not worth buying the REx in that case, and lugging it around everywhere you go, and reducing the battery's effective useable range by 10-30% (depending on how you look at the efficiency advantages of the BEV).

I just don't know if the BEV alone will work either… in very cold weather I'm worried the range will be something like 20-30 miles.

Hmmm…. I love the i3 but living in cold climates and needing it for highway driving may not be a good fit, REx or no REx.