Undoing the lease!?!

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Max

Member
Joined
Dec 19, 2015
Messages
7
Just leased an i3 from an out of town dealer. Was stunned to realize when half way home that the car in Rex mode is incapable of going the 70mph highway speed limit. Was stuck going 52 mph up a slight incline while semi trucks came bearing down on me. I couldn't consistently keep a speed anywhere near 70.

Bought the Rex thinking I'd be able to do road trips with just the inconvenience of frequent fill ups, but didn't realize I'd be stuck with a dangerously slow car incapable of driving at a standard speed.

So does BMW have a standard way out of this? Or will it have to get messy with lawyers and state lemon laws? I travel out of town far too frequently to have a car that can't go more than 45 minutes on the highway without becoming a sputtering traffic hazard.
 
The reason that you were unable to maintain 70 mph up an incline was because the output of the REx generator was insufficient to maintain the battery pack's charge level. The REx engine doesn't start until the battery pack's charge level drops to 6%, and power reduction begins when the charge level drops to 2%, so there's not much of a cushion between normal and reduced power.

Many U.S. REx owners have modified settings (incorrectly called "coding") to enable Hold State of Charge (HSOC) mode and to make available the entire 2.5 gallon gasoline tank capacity which are standard in all other i3 markets outside North America. This allows the driver to manually start the REx engine whenever the battery pack's charge level is less than 75% rather than wait until the REx engine automatically starts at 6%. This increases the cushion so much that there might be no roads in the U.S. where an i3 could not maintain the speed limit.

Had HSOC mode been available, you could have started the REx engine when the charge level dropped to 75% and continued driving 70 mph until you needed to stop for more gasoline. It is unlikely that your battery pack's charge level would have dropped so low that power was reduced. With more useable gasoline, you would have been able to drive farther before filling up.

If you have a Windows laptop, purchased the appropriate Ethernet-to-OBD port cable, and can follow coding instructions, you could change these settings yourself. Otherwise, you could pay someone to change these settings. Others on this forum will undoubtedly provide the information you need to make these changes.
 
A - confirm that your car has the NOV 2015 software update
B - modifying settings should not void any warranty; the fact that the dealer can simply do a "reset" of the software to factory defaults shows that nothing has been "harmed" by the modification; additionally, it will be hard for them to argue that operating the vehicle in that state harms the vehicle since you are simply modifying the settings to others that are contained within the very software that runs the vehicle and which are available in other geographies
C - understand the dealer does not want settings to be modified because they deal with the consequences when done incorrectly. They can discourage it if they want, but they should not be saying that doing so voids the warranty.
D - there is a reason behind the 6% setting; it was to get CARB approval in CA; without that, it is unlikely that the i3 would have been economically feasible; while we would like a "CA and non-CA" switch in the car, that is not the way it works and if you want the development you have to accept some bizarre circumstances that go along with getting there
E - if you are planning to frequently use the car beyond its battery only range, you either need to be aware of the limitations or be prepared to modify the settings to avoid them. If you didn't have a good client advisor that talked through all these issues with you, shame on them. However, a bit of "buyer beware" is on you as well.

Good luck.
 
I can confirm jpa2825 said about changing the code will not void the warranty. My salesman suggested I have this done, and the person who did it is my technician at the dealership.
 
Once your battery pack gets quite low, think about the fact that the REx is a 34hp engine...when was the last time you drove a car with a 34hp motor? You can't get blood from a stone...but, by taking advantage of averaging the load, the REx can be made to turn on earlier and avoid getting the batteries low enough to cause issues MOST of the time. There are some unusual circumstances that might cause the car to get there regardless of when you turn it on.

There is a software update coming (it's late, was expected already) that, if you put in a route, and thus inform the car's computer about where you plan to be driving, that it can overcome the CAFE rule and let the REx turn on earlier to avoid that problem. This would be automatic IF you use a route (otherwise, the car wouldn't know your intentions) and keep within the intent of the CAFE rules it's trying to abide by. The nav system knows the elevation changes, and can anticipate the problem and overcome it by turning the REx on earlier. IMHO, this is probably better than manually turning it on, as the car will remember, you may not! But, it is not here yet. The workaround is to program it to take advantage of the code the rest of the world has on the i3 as delivered.
 
The problem with taking this approach is that forcing the ICE to run turns the I3 from a 124 MPGe electric car into a 39 MPG hybrid. If one has to do this frequently, it would be more efficient to drive a Prius.

BMW should have provided a bigger ICE engine for the Rex, one capable of driving the car at normal highway speeds. According to fueleconomy.gov, the I3Rex gets 39 MPG combined while running on gas. By comparison, the Volt, which has a bigger engine and runs fine on the highway, gets 42 MPG on gas, even though it's a much larger car.

I think the Rex engine is undersized or in some manner not optimum for highway use. It's intended as a limp-home safety net.
 
michaelbmw said:
I think the Rex engine is undersized or in some manner not optimum for highway use. It's intended as a limp-home safety net.
The BMW i3 was designed as a city/urban car, and with the idea that the average user drives about 34-miles/day. Designed for that goal, it works just fine. Trying to use it in other modes is possible, but it has limitations. If they meet with your needs, great, otherwise, it is not the car for you!

The i5 or i6 or whatever comes next is purported to be designed for an ICE replacement...IOW, full range with no compromises. The i3 works great for what it was designed for, and if you understand and can accept its limitations.
 
michaelbmw said:
The problem with taking this approach is that forcing the ICE to run turns the I3 from a 124 MPGe electric car into a 39 MPG hybrid. If one has to do this frequently, it would be more efficient to drive a Prius.

If you never, ever charged or used the battery.

Why would you buy an electric car with a range extender for occasional use and only run it on the range extender?

I guess, there is always a loophole in the statistics that someone can use to claim that the most efficient platform is a failure. If you buy a car with an EV range of 72 miles to drive 200 miles a day you're just buying the wrong vehicle, you can't then blame the vehicle for your poor decision making.

The vast majority of commuters in the US would be fine with a 72 mile range:
commute_US.jpg

http://www.statisticbrain.com/commute-statistics/
 
michaelbmw said:
The problem with taking this approach is that forcing the ICE to run turns the I3 from a 124 MPGe electric car into a 39 MPG hybrid. If one has to do this frequently, it would be more efficient to drive a Prius.
FWIW, I have found that my REx MPG is closer to 47-50 - granted, this is running it in HSOC mode. I imagine running it in standard mode at 6% puts more strain on it to maintain SOC, so 39mpg is probably realistic in that scenario.

But even then, when you average out the electric and ICE MPG(e), you are looking at about 70 miles at 120+ MPGe and about 70 miles at 39 MPG - averaged that is 79.5 MPG, which no Range Extended EV or PHEV can touch.
 
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