REX reliability

Not being able to turn on and test the REX before the mileage is down to 5% is also a reliability problem.

I essentially use my i3 as BEV although I have the REX option. Having the REX is suppose to take all the range anxiety away especially when now in the winter the range is much smaller and less predictable.

Unfortunately, I have just realized that this is not going to work.

Why? Because the REX is unreliable and you cannot test it when you have enough batter range left.

Last week, I got a message which approximately stated that it was going to turn on the REX for a maintenance run because of lack of use. To cut a long story short, the REX failed to start, I have the CEL on and an appointment with BMW.

This is now a problem for me because I cannot test the REX when I have some power left (more than 5% but less than 75%). I have either experiment myself by making a special short distance trip close to 5% power so that I can get home if the REX does not work.

Another important reason for BMW to ditch the 5% level start requirement in US.

I've had my REx over 4 months and 6000+ miles and have never used the REx but have gone through 3 maintenance cycles. Fortunately it appears to be working as expected but the worst time to test something is when you actually need it so you make a good point. But there's no guarantee that something will work even if you tested it before There is a way to turn the REx on for testing while parked with a somewhat complicated procedure for smog checks etc. but don't have the details in front of me.

Neil

I believe there is a test you can perform when the car is stopped.

Ah, just found it:
http://www.mybmwi3.com/forum/viewtopic.php?f=12&t=966&p=11202#p11202

blueq said:

I believe there is a test you can perform when the car is stopped.

Ah, just found it:
http://www.mybmwi3.com/forum/viewtopic.php?f=12&t=966&p=11202#p11202

Click to expand...

Thanks, will try this.

Neil said:

I've had my REx over 4 months and 6000+ miles and have never used the REx but have gone through 3 maintenance cycles. Fortunately it appears to be working as expected but the worst time to test something is when you actually need it so you make a good point. But there's no guarantee that something will work even if you tested it before There is a way to turn the REx on for testing while parked with a somewhat complicated procedure for smog checks etc. but don't have the details in front of me.

Neil

Click to expand...

Sounds like a BEV would've worked for you.

i3atl said:

Sounds like a BEV would've worked for you.

Click to expand...

I knew someone was going to say that. Up to now, yes.

It was a tough choice (I really wanted the BEV) but with a 75 mile round trip commute to work at 75mph for almost 70 of those miles it was too close for comfort given all the unknowns. No 3 day test drive at that time to find out either. My bottom line was that I had to guarantee I could make it to work and back home without a charge in all weather and including the possible battery degradation to 70% in the coming years. Fortunately I have been able to charge at work every day, but I had to consider that the charger might be out of order someday for a while or there would be a power failure at work (it has happened), or eventually I might not be able to get on the charger as more EVs show up.

I usually get to work with about 30-40% of charge left (colder in morning and 300 foot elevation gain) and home with (40-45%) left both starting with a full charge (Very rough numbers). But I do much better when the traffic is bad.

So even though I haven't used any extra gas up to now, I know I made the right choice going with the REx. If the BEV would have had another 40 miles of range, I could have gone with that.

Neil

First time I hear of a REx not starting when needed. Unusual. Mine has worked flawlessly so far.
You may not hear it when it starts. Sure it didn`t?

Frank

I am sure it did not stay running, even if it did start, for more than a few moments.

Many indications of problem:
1) When the REX is working, the fuel gauge goes from grey to white. This happened for a second the first time and then went back to grey.
2) The CEL light came on and stayed on.
3) There was a message on the nav screen which said that maintenance cycle could not be run because the fuel was low (not - it was actually 95% full) or so above 75% (also not true as it was around 50%).
4) The same thing happened a few more times, every time I re-started and with the battery soc successively lower, well below 25% the last time.
5) Just to be sure, I ran down the battery by driving in the neighborhood around the house to get so below 5%. The REX tried to start but failed, giving the same message.

One thing to check...the i3's fuel system must be pressurized to provide fuel to the motor. If the fuel filler cap is not properly tightened, it will not be able to pressurize the system, and the motor won't run, or if it does, it will quickly run out of fuel. Make sure that the cap is fully tightened down - it could be operator error, not a system fault.

Had a similar issue a couple of days ago.

Drove 8 miles to work (mostly downhill), then out to Riverside and back at 90 miles (so the Rex kicked in about a third of the way from the office). Parked for the rest of the day then home - the error message said the Rex had quit and that I could only drive on battery (which of course had almost no charge). Several starts and stops later I made it home. Had a stated 50 miles left on the gas tank. 65 degree weather.

So either the Rex loses (or does not hold) pressure enough to get on? The road home is 35 mph but is back up a 2.5% grade. It would be nice to have a better understanding of what the Rex needs for optimal performance in the US version.

I have driven 135 miles continually at 68 mph to a charging station and added 3/4 of a tank of gas. Then back with no issues at the end of a day.

MAB

That is clearly a mistake. Would take that to BMW.

Frank