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Looking to buy a BMW I3 REX

Posted: Thu Jan 10, 2019 9:22 pm
by bostonbruins8703
Hello everyone, I'm obviously new this forum. I'm currently a Prius owner. I've had my car for nearly 2 years, zero issues out of her, done maintenance as scheduled at the dealership. However, the overall buying experience was a nightmare. Long story short, the dealership tried screwing me over on the value of my trade in. Anyway, I was pretty much forced into getting the Prius.

For the last couple months, I've been doing so much research on EVs. I've been bitten by the bug I guess. I'm tired of paying $25 a week to fill up my car, I'm tired of dishing out money for oil changes and routine maintenance every few months. My commute to work is an hour away, in total, I'm driving 109 miles a day, 5 to 6 days a week, not counting road trips with the family on the weekends/time off. I really want a EV, however the Tesla is to far out of my price range and honestly, I don't think they have the reliability behind their brand yet. The other EVs on the market are either to out of my price range or the actual EV range makes me to nervous to take the plunge and invest. We've got a decent amount of charging points here in Massachusetts. About a 20 mins from my house and about half hour away from work. The only car on the market that really intrigues me is the BMW I3 REX. I'm not picky about the actual trim/model details. I just want something that gets me from point A to point B without using as much gas as possible or dealing with range anxiety. The REX in my opinion offers the backup plan for when you run out of juice and paying a few bucks at the pump for that assurance is worth it.

As of right now, they are a number of 2015s for sale in my general area and from what I've read online, it seems thats one of the best models to date as that they've been on the road for a little bit to prove their reliability. Quiet a few I've seen online run between $15,000-$17,000.

What makes me nervous from everything that I've read online, people either hate the car or love the car. And they are some who've had little to no issues to some who've had major issues. One being the power that the REX doesn't give the battery enough power when going up steep grades/large hills and in my area, they are several large hills that you really have to floor the pedal to get up. Then they are stories I've read where dealers either don't know enough about the car or they try sticking it to the potential buyers. And they're is the tire issues that seems to be a common problem, which I've look online for the sizes for the REX and I found Bridgestone Ecopia for the front and back, totaling around $538 on ebay sold by Tirehero. I don't know what many miles these tires can go up too. So I'm a little weary about having to replace them every 12,000-20,000 miles from what I hear is a common issue amongst most owners.

Anyway, I'm looking for advice on rather or not if this is the right choice for me. Any feedback and advice is welcomed!!

Re: Looking to buy a BMW I3 REX

Posted: Thu Jan 10, 2019 11:13 pm
by alohart
The REx model was designed to occasionally extend the range enough to reach a charging location, not for routine daily usage although many REx owners do just that. Your Prius would be more fuel efficient than a REx while the REx engine is running (only 35-40 mpg). A 2015 REx is rated by the E.P.A. for 72 miles range before the REx engine starts. In cold weather and/or at highway speeds, the REx engine would start before 72 miles, so in your commute, you would be running on the REx generator through about half of your commute distance in cold weather unless you could charge at work. You'd probably save a little on gasoline costs, but not very much.

If you want to commute on electricity rather than gasoline (and we all should), a Chevy Bolt would likely be the most appropriate choice for the money. A used Bolt would be more expensive to buy than a 2015 i3 REx, but you might be surprised by how little the total cost of ownership might differ considering that you would have no gasoline costs. A Bolt could easily complete your commute even in cold weather. Parts and service would almost certainly be less expensive than for an i3.

Re: Looking to buy a BMW I3 REX

Posted: Thu Jan 10, 2019 11:25 pm
by jadnashuanh
Unless you can recharge at least some each day, you're going to end up using a little gasoline. The newer versions, with the larger battery, can probably do that without running the engine, at least when the weather is milder. The total range does go down a significant amount when it's really cold out.

The REx engine still comes with oil changes, muffler, coolant, and spark plugs, etc. It's just that there are two of them, and the volumes needed are smaller. The engine is only in the order of 34hp. The electric motor is 170hp...while 34hp is fine for cruising at moderate speeds, some of the faster roads around Boston often are traveling closer to 75mph unless gridlocked. WHen you start going faster, and use more power than the REx can supply, your battery charge level will drop. Otherwise, it will try to maintain the level. It isn't really setup to recharge the battery, only to try to restore the level when it was turned on. Unless you recode the car, that's 6%. If you recode it, you can set the REx to turn on at 75%. The power required as you go faster can overwhelm the REx. But, the REx never drives the wheels...it runs a generator. If your battery level is allowed to drop below 6% is when you'll start to have the car shut down things to preserve the battery. So, motor power is always coming from the batteries, and the REx engine, when on, tries to limit that amount, and sometimes, slowly build it back up to that magic turn on time you engaged (it's automatic at 6%, but could be higher if you manually turned it on).

Something like a Prius can just keep driving as long as you refill the fuel tank, and can go quite a long ways before that's necessary. The i3 isn't designed or built that way.

IMHO, a 109-mile daily commute, unless you can recharge at work, is asking a bit much. Yes, it will do it, but you may not like the inconvenience. The newest ones, won't have depreciated anywhere as much, could. The car is a lot of fun to drive.

Tires will likely wear out about 20K, depends on how you drive it. Also, you will want to buy a set of winter tires/wheels for the thing. If you choose one with the 20", summer tires, that would be mandatory, but still highly recommended if yours has 19", even the all-seasons (which I consider a compromise, all seasons). All seasons are much better than even 5-years ago, but still can't approach a good winter tire (I think the Nokia R3 is probably the best one that fits), but the OEM Bridgestones aren't bad. So far this year, Boston has had essentially no snow, but winter tires just stop and turn better when it's cold out, too. Throw in some ice and snow, and they're superior to an all season or summer tire, in the case of the later, hugely.

Re: Looking to buy a BMW I3 REX

Posted: Fri Jan 11, 2019 12:02 am
by TheMK
Man, what a commute. I'd die if I had to drive that far every day! I hate driving the 20-ish miles that I have to drive 4 days in the week.


You could drive your 109mi commute in the i3 REx without issue. You could either let the car do the REx management (wait until the battery drops until 6.5% SOC), or you could manually engage it at any point below 75%* and use it only while cruising on a highway/freeway. Now, I have the i3 REx, and I've used it to make some longer trips, including a 350mi one, as well as relatively shorter ~100mi trips. The problem isn't that the car could drive that distance, it's the convenience of driving that. The i3 REx's gas tank is only 2.3 gallons* (9L to be exact). Let's take the EPA's official range rating which is pretty spot on for typical American driving patterns of 72 miles. 109-72=37 miles (at least) on the REx. Depending on how risky you'll cut it, you may leave yourself a bigger battery buffer and burn more gasoline to keep a higher state of charge. The REx engine get's around 40MPG in my experience (EPA rates it at 39MPG). This means that you'll be burning approximately 1 gallon of gas per day**. If you commute 6 days a week, you will need to refill about 3 times a week-not exactly convenient. Now, things look better if you can recharge at work (or whatever your destination is), and, depending on how long you can charge, you may not burn any gasoline at all, if you could recover that 40 or so miles while at work.
The tables turn slightly if you can get into a 2017 or 2018 with a 94Ah battery, this battery is now good for 100mi electric range, and depending on how much you hyper mile it, you might even make it to 109mi without burning a drop of gasoline.


Personally, I love the i3 REx, it's a fantastic vehicle, that definitely fits my needs. I find the little 38HP 2-cylinder engine to be plenty adequate for what I've thrown at it. That being said, it's not the car I would take on a 109mi trip daily, unless I had the 2017-18 94Ah (or the new 2019 120Ah) model. If you did a 109mi trip, say once a week, then the i3 REx would be a perfect car, but going to the gas station multiple times a week would get old for me super quickly. I've taken my car on a couple of 100+ mile trips, and using the REx worked out phenomenally, but if that were my daily drive plan, I'd look into destination charging options (to reduce the amount of gasoline I'd burn therefore making it so I'd have to fill up, say once a week), or simply another vehicle. The car comes with a standard 120V charge cord, so if your work building has 120V outlets outside, you could plug in (maybe bring an extension cord?). While slow, over the course of an 8 hour work day it would add significant range, enough to possibly cancel out needing the REx. Then, you could use the REx on the weekends to drive how ever far you want- just don't let the battery buffer get too low. On my long trips I start the REx at around 70% so I can keep the battery up, since I know I will be burning gasoline regardless, there's no point in delaying it.


*The default limits in the U.S.A. is that the REx only turns on when the battery is at 6.5% (or lower), and the gas tank is 1.9 gallons (7.2L). Getting around those limitations is easy, as it's software only. The procedure to unlock that is well documented.

**You might think this is great, driving 109 miles with one gallon of gas, and it is! In my old car before my i3 I would burn about a gallon of gas a day driving a much smaller distance.