Are REX problems worth it?

[JimBmwi3s]

I have been flip flopping. As I search for the right i3s, I read forums where BMW dealers are charging $1000s of dollars when i3 owners run into REX problems. I get the anxiety range, but I am thinking many owners must hold their breath before turning on the REX and have a relief of anxiety when it works. I read of posters complaining of the back and forth to the BMW dealer and mounting costs each time the repair didn’t work. It’s a motor cycle engine which seems should be easy to simply swamp out like on a bike. I read yesterday of a guy up to $10k and not working. If one had a non-REX, are there less headaches and things to go wrong?

 

[eNate]

The real question you ought to be asking is "Do I need a REX?"

My first i3 was a 135 mile range BEV and initially I i assumed that wouldn't be enough. But I crawled through a year of Goodie Maps driving data and saw that I only exceeded that driving distance on a few occasions.

After purchasing, I did drive some longer trips, knowing in advance I'd need to charge. A minor inconvenience, but DCFC options near me are plentiful.

So based on my particular set of needs, the REX would be more of a liability than a benefit. And honestly, if I needed greater range on a regular basis, I'd choose a different car. For instance I'm sure I could be at peace with stopping for a charge once a week if I took a regular long weekend excursion, but if it was part of my daily commute I wouldn't tolerate it (or the REX).

 

[Nanniepoo]

That's too hard of a question to just answer for you.

I have a 2015 with the REX that I've had since 2019. I wanted one with the REX due to range anxiety. In actual use though, 99.5% of my use doesn't need the REX and it's dead weight. That <1% could probably be covered with a newer i3 battery range, or we have two cars and if I know I'm doing anything close to the range of the i3 I could just take the X5.

So to more directly answer your question, I've had exactly zero problems with the REX. However doing it again I would not buy one with a REX. I have no desire nor patience that even though I have the capability to drive wherever whenever and use gas that I need to refuel every hour. So why have it when basically the majority of my fuel use is just to do the maintenance cycles, plus the extra maintenance (still much less than a typical ICE, but still has oil, spark plugs, etc). And if I regularly needed to use the REX I probably would just buy a different car.

 

[JimBmwi3s]

Most of the i3s 2020-2021 come with a REX. At first I wanted a REX, but got turned off after reading posts of owners complaints of REX related issues that require BMW dealer intervention and $1000s to fix. My thinking a BEV would eliminate this extra burden if using car for errands or small trips. Could use on rare occasions for 160 mile round trip if charging 1/2 way so it seems a BEV is fine.

 

[JohnnyCakes]

People complain. It's what they do. You are not going to have someone start a thread with the topic, "Nothing has gone wrong with my REX."

I have had zero problems with my 2015 REX. Mostly I don't need it, but am comforted that it is there. On occasion, I visit a friend who lives 400 miles away. I can do that easily, with or without charging along the way. If the gas station is at the top of the exit ramp on your side of the highway, I have learned that a gas stop takes three to four minutes from exit ramp to entrance ramp.

 

[duanew]

The most reliable REX are the ones that use them. I try to use mine twice a month to keep it active. I also put some seafoam in the tank when not on long trips.

 

[jfran2]

JohnnyCakes hit the nail on the head - people don't write in to forums like this unless they have problems, so we rarely hear from the thousands of happy REX users like me. I think it really depends on your typical use case. I've often thought I'd be happy with a BEV if I could have 150 mile range. But my 2015 REX is lucky to get a range of 55 miles on warm days, and during this recent midwestern cold snap, was down to about 35 miles on a full charge. It's still useful as a strictly around-town car in my small town, but with the REX, I can take it anywhere, on whatever combination of gas and electricity seems the most expedient for the trip at hand. I live 110 miles from the nearest big city, and my wife and I take a monthly shopping trip there, using gas on the Interstate and only electricity in town. The REX just makes the car that much more useful for us! If I felt like making a car payment again, I'd consider a newer BEV, but the 2015 has been paid off for a few years now, and still working great.

John Francis
Rolla, MO

 

[kweiske]

I have been flip flopping. As I search for the right i3s, I read forums where BMW dealers are charging $1000s of dollars when i3 owners run into REX problems. I get the anxiety range, but I am thinking many owners must hold their breath before turning on the REX and have a relief of anxiety when it works. I read of posters complaining of the back and forth to the BMW dealer and mounting costs each time the repair didn’t work. It’s a motor cycle engine which seems should be easy to simply swamp out like on a bike. I read yesterday of a guy up to $10k and not working. If one had a non-REX, are there less headaches and things to go wrong?

I just bought a 2018 i3 with REX a few months back. It's my first EV, replacing a Plug-in Prius. We're a 2-car family, so there's no dependency on the i3.

Going from 460+ miles on a tank to 110-120 miles of EV range was an adjustment, even though most of my driving is city driving or highway well within the range of the battery. Just knowing that I had another 70 miles of reserve with the REX was reassuring.

Without knowing the state of charging availability, the range extender made sense. it alleviated any range anxiety and opens the possibility for longer drives. Given that public charging is *ok* where I am, and I can do most of my charging overnight with a level 2 charger, I've only needed the REX once or twice.

Knowing what I know now, If I bought a 2019+ i3 with the larger battery, I'd probably skip the REX and get that nifty looking trunk extension - WOKEBY - products - BMW i3 Trunk Extension.

 

[Allenpien]

I3 REX problems. When I bought my I3, I was advised by Basney BMW to contact Bimmer Tech and have my REX modified to get a hold charge at 75% option. That was great advice. This allows me to use the REX when the battery goes down to 75%. This feature has been deleted on ALL American cars in response to the CARB rules. Because I regularly use my REX to hold charge, I have not had any problems with it YET. Like any gasoline engine, the worst thing you can do to a classic car is to never drive it. I live on the snowy shore of Lake Michigan in Indiana. I have had no problems with the car in the recent awful cold snap. When home, it is always on the charger. I think the lack of home charging is why there have been a lot of Tesla problems during our recent cold snap. My I3 has always been ready to go with 100% charge in the morning.

 

[Colinh]

I’m another happy REX owner (2015) with no issues. The trip to our caravan is 141 miles with a bit of Welsh hills thrown in and the REX means we can get over the tops and down into Bala to the rapid charger. Love the car but it now shares the drive with a Tesla Y - which does all the long trips for us!

 

[Edszhi1]

I have been flip flopping. As I search for the right i3s, I read forums where BMW dealers are charging $1000s of dollars when i3 owners run into REX problems. I get the anxiety range, but I am thinking many owners must hold their breath before turning on the REX and have a relief of anxiety when it works. I read of posters complaining of the back and forth to the BMW dealer and mounting costs each time the repair didn’t work. It’s a motor cycle engine which seems should be easy to simply swamp out like on a bike. I read yesterday of a guy up to $10k and not working. If one had a non-REX, are there less headaches and things to go wrong?

I had range anxiety on my first i3 (2014) so I got a REX, even though it didn't function like the European REXs because of CARB rules in the US. With 60 miles of range I exceeded it about twice a month and needed to charge on the road or use REX. With now 150 miles of range on the 2020 i3S I didn't get REX. If we didn't have a second car and needed to leave the city I could always rent. I think people think of the "road trip" they take once or twice a year and decide to get a REX because of that. You could just rent a car for road trips and focus the i3 on what it is best for...commuting every day.

 

[cpallenjr]

My situation is much like John Francis’ above. I bought a used 2017 Rex and haven’t had any problems with it so far. I tend to use it once a month during trips to the “big city” while driving on the interstate. I go back to battery when in town, and then the Rex again on the way home. Otherwise, I’m just using the battery day to day, charging at home at night on a Level 2 charger in the garage at a rate of about 12 cents per kilowatt hour. It helps to have used the Bimmercode app to enable the European Hold State of Charge function which allows me to turn the Rex on and off at more or less at will. I also fill the tank with a quality ethanol-free premium gas.

I haven’t driven the i3 during this recent cold and snowy weather. I live in a rural area, and my AWD Honda Ridgeline is a much better vehicle for this, so the i3 is sitting on the charger in the garage. I love the i3 but to quote my hero Dirty Harry “It’s important for a man (car) to know its limitations.”

 

[2018REDI3s]

I have been flip flopping. As I search for the right i3s, I read forums where BMW dealers are charging $1000s of dollars when i3 owners run into REX problems. I get the anxiety range, but I am thinking many owners must hold their breath before turning on the REX and have a relief of anxiety when it works. I read of posters complaining of the back and forth to the BMW dealer and mounting costs each time the repair didn’t work. It’s a motor cycle engine which seems should be easy to simply swamp out like on a bike. I read yesterday of a guy up to $10k and not working. If one had a non-REX, are there less headaches and things to go wrong?

JImBMWi3s- I have a 2018 I3s, no rex and I know what you mean by range anxiety. I had it for about 6 months after I bought my I3. It only takes one time of being short on the range to learn your lesson. It all went away after I invested in a 200-300 dollar charger and that included getting the 220 outlet installed in my garage. My range on a warm day is about 120 miles but if you turn on the AC, drive 70/mph then it drops down to 100-110 - it all depends on the weather temperature. Now it's been cold in Dallas and a full charge gets me about 90-105 miles - heaters, seat warmers reduce the range as well as the temp. Now the only time I visit the gas station is to fill up my wife's car. I'm glad I bought the non REX version- no oil, no gas, no problems.
Don't get me wrong, I've still had to go to the dealer for brakes, brake fluids, etc. and minor issues but it's the price we pay for having good running cars.
Good luck my friend.

 

[ksnax]

Don't let having a REx stop you from getting one if the car otherwise suits your needs and price. You aren't required to use it - though it will nag for the maintenance cycle to run. Worst case, it's dead weight with error codes that otherwise don't change how the rest of the car functions.

 

[Jim0el]

I bought my 2017 i3 REx in the spring of '20. I love having the REx for backup whenever I might need the range, and it has never had any glitches. I've only done one long trip, 1500 miles round trip, along a rural highway through eastern Oregon and Washington, all in four days. The REx made it possible, with no anxiety.

 

[eNate]

Lest anybody think it not possible, long trips are available to BEV owners, too, such as the 1,700 mile San Antonio to Oakland trip I drove in 48 hours, written up elsewhere on this forum.

 

[RhodyDave]

JohnnyCakes hit the nail on the head - people don't write in to forums like this unless they have problems, so we rarely hear from the thousands of happy REX users like me. I think it really depends on your typical use case. I've often thought I'd be happy with a BEV if I could have 150 mile range. But my 2015 REX is lucky to get a range of 55 miles on warm days, and during this recent midwestern cold snap, was down to about 35 miles on a full charge. It's still useful as a strictly around-town car in my small town, but with the REX, I can take it anywhere, on whatever combination of gas and electricity seems the most expedient for the trip at hand. I live 110 miles from the nearest big city, and my wife and I take a monthly shopping trip there, using gas on the Interstate and only electricity in town. The REX just makes the car that much more useful for us! If I felt like making a car payment again, I'd consider a newer BEV, but the 2015 has been paid off for a few years now, and still working great.

John Francis
Rolla, MO

Hey John, where did your Francis family come from? Mine's from Baltimore County, MD. Been there since 1760s! But it turns out I'm actually a Kimble! My great grandmother had a fling and my Y-DNA doesn't match Francis males. Took me about 20 years to unravel that mystery.

There were Francis families in many of the 13 colonies. A famous man here in RI came from Philly and married a daughter of John Brown (as in Brown University). There's a Francis Street downtown named for him. In England & Scotland, Francis just meant someone who came from France.

I also have a REx in my 2018 i3. I use it often enough to clear the stale gas out of the tank. I just don't drive that much any more. But I don't worry about my range, either!

RhodyDave

 

[weajd]

There is an advantage to the REX if you register it in California. Not sure where you are located and whether this applies to you.
BMW reached an agreement with California on the REX to qualify with smog requirements.
The REX and gas/smog components (maybe the battery too) for it are warrantied for 15 years in California.
It may be difficult to get the BWM dealer to honor this. Some posted information about this on the web.
With the BEV, it only has an eight year warranty on the battery in California.

On the other hand, dealers are usually looking for $1000 to $2000 more for the REX.
Personally, I think you want the REX on the 2015-2016, and the 2017-2018 versions.
Not so much on the 2019-2021 versions.

 

[Badgersbits]

Buy a full EV and if you want peace of mind stick a Honda generator in the boot.

 

[user 9975]

I have owned 3 i3 REX's since 2015, here's my take. My 2015 and 2018 were rock solid no issues using the REX feature mostly in maintenance mode, as I rarely drive over 35-40 miles a day anywhere and had access to charging when I needed to. My 2021 i3s REX has experienced a number of problems (only 18,000 miles on now) including driver seat heater out every winter season (3), a broken sun roof mount which required the entire sunroof assembly and glass to be replaced, and an annoying knock in the front and sunroof area. All under warranty, and none related to the REX. For me, I would not buy an i3 without the REX (even with these issues) as at best I am getting 240 range which helps manage the big cold weather draw down and hot weather as well, so I never worry about having enough range. In many ways this car is a brilliant solution where unlike Hybrids that run 30 miles on electric, the i3 actually is the better solution with 95% of use on the battery, then the extended generator does the rest. I also did the Mods with Bimmer Code and BT device (I forget brand name), which allows me to run the small motor when desired along with a host of other tweaks I did to the car. I did have a BMW tech who also drove an i3, tell me that the BEV's have less issues overall. At the end of the day, whether it's the REX or BEV, either is far better maintenance wise than our gas/petro counterparts on maintenance, perhaps with exception of Toyota or Honda. And as a small note, I went from an Audi D3 V10 to the BMW i3 in 2015 because my Audi was in the shop for 7 months at one point! True story. While there i3s isn't quite my style, any household that has 2 or more cars should have one in it's fleet for the 80% of local travel everyone typically does, unless you need a long range hauler.