2017 BMW i3 Rex (94 Ah) Arrives In US, Rated At 97 Miles AER, 180 Total Miles

SEP 10 2016 BY JAY COLE 48

The 2017 BMW i3 with improved, larger battery option was first announced over four months ago.

And immediately we heard that the 2017 edition would arrive with a 33.2 kWh (94 Ah) option, good for 114 miles of range in the all-electric version – a 41% improvement over the earlier BEV version of the car.

As for the extended range, BMW i3 REx…nothing on the range or efficiency.

BMW i3 REx Gas Tank Location - Full 2.4 reservoir now available in 2017 33 kWh edition in US

BMW i3 REx Gas Tank Location – Full 2.4 reservoir now available in 2017 33.2 kWh edition in US

All we heard at the time was that the 2017 plug-in hybrid BMW would also receive the 33.2 kWh battery option, and now also use the full 2.4 gallon gas tank as in the European version .

Of note: The earlier 22 kWh (actually 21.6 kWh) version of the i3 REx in the US was electronically capped at 1.9 gallons in order to comply with CARB compliance regulations for BEVx status.

Even now, the EPA has yet to formally publish the range ratings for the i3 REx on their website.

Fortunately, the BMW i3 REx (like its BEV sister-car last week) has finally been released from port holding in the US, and we have an actual shot of the Monroney window (below) found on some just arrived, dealer inventory cars – thanks to InsideEVs contributor Warren M)

And the news is…well, its not that great.

The 2017 BMW i3 REx has an all-electric range of 97 miles, with the new, as promised, 2.4 gallon fuel tank enabling a further 83 miles of driving, for a total range of 180 miles – which translates to just 30 more net miles over the 2016 i3 REx.

The longer range, 2017 BMW i3 REx starts from $47,450 (+995 dst), $1,200 more than the 22 kWh/2016 edition.

Here is a comparison between the original 22 kWh BMW i3 REx and the newer 2017 edition:

2017 BMW i3 REx (33 kWh) vs 2016 BMW i3 REx (22 kWh)

2017 BMW i3 REx (33 kWh) vs 2016 BMW i3 REx (22 kWh)

2017 BMW i3 22 kWh/60 vs 2017 BMW Ah Versus i3 94 33.2 kWh/Ah: +34 more range

2017 BMW i3 22 kWh/60 vs 2017 BMW Ah Versus i3 94 33.2 kWh/Ah: +34 more range

Clearly we can see that the 54% larger battery translated to just a 34% increase in all electric range, and the new 26% larger fuel tank has translated to only 6% more range on petrol, while the extended range efficiency overall has dropped significantly.

Interesting, the same battery upgrade in the all-electric version added 4 more miles overall (34 miles total, moving from 81 miles to 114) than was added in the REx, despite the extended range BMW also adding that extra half gallon of petrol capacity.

Why the lower improvements in range, especially on the gas extender?  Perhaps the performance operation of the BMW i3, often criticized for being under-powered while driving on gas in the US (and sometimes leading to a lawsuit for its “Reduced Power Mode”), has been dialed up to better fit consumer demand.

2017 BMW i3 REx (33 kWh/94 Ah) Window Sticker (click to enlarge)

2017 BMW i3 REx (33 kWh/94 Ah) Window Sticker (click to enlarge)

Hat tip to Warren M!

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48 Comments on "2017 BMW i3 Rex (94 Ah) Arrives In US, Rated At 97 Miles AER, 180 Total Miles"

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I must say, that’s a pretty lame upgrade, considering the price increase. Plus, $49k for a base model i3 Rex is steep.

They sell the i3 for the Same Money as an eGolf over here in Germany.

I guess if they would go down to the low-mid 30s in the US too, the i3 would be even more successful.

Hardly a lame upgrade if you consider not having to turn your hazards on while climbing long hills on an empty battery. I’m 100% certain that’s why the range increase isn’t as significant as it is for the BEV, and I think it’s a great call. The REx is pointless if you can’t use it for long distances.

Why would you climb hills on empty battery? Would you do that on empty tank as well?

Just unlock the car and use the RE before you run out of juice. Like it was designed for.

Larger tank is a good news. It means a simple software unlock will convert the car to a non-US version.

Tank is not larger, just unlocked when you buy it so no hacking required.

2.4 gallons is still silly. But it’s easy to take a 5 gallon can with you on trips.

That’s not what Mike is speaking of. He’s not talking about the extra half gallon of gas. He’s talking about illegally altering the software that controls the CARB standards. CARB requires the battery to be discharged almost completely before the REX kicks in to qualify for the California credit. This is different than European requirements. In this condition the battery can be completely depleted at the start of a hill climb and the Rex doesn’t have enough power to keep it at highway speeds up a steep prolonged grade. This can be avoided by altering the software to allow a ‘hold’ mode that allows you to specify the electrical battery level at which the Rex kicks in. If you set it at 30% for instance then you can go into the climb on full power of the electrical motor. But it’s illegal and voids your warranty so it is a stupid comment to say ‘why don’t you just….’. It’s a better question to ask BMW why they don’t offer the non-crippled version in non-California states where there’s no difference in rebate.

“Why would you climb a hill on an empty battery?”

Because you’re a mainstream owner and not an engineer or someone who frequents and EV blog and maybe doesn’t have the same appreciation of what’s going on under the hood.

These numbers are really strange. I hope we get explanation for this. Fixing the uphill extender power loss shouldn’t affect gas range and certainly it wouldn’t affect electric range.

Something smells fishy… I have the i3 REX. Have driven it many times with heavier loads. Never saw such huge consumption increases with load. The new batt weighs maybe 50kg more than the old one. There’s just no way it would make such a difference in consumption!

I totally agree. Something else must explain the huge drop in efficiency.

Yeah absolutely doesn’t make any sense how a LEAF is heavier than a Rex and yet can go an EPA rated 107 mi? On a smaller 30kWh battery? Go figure. Unless there has been major efficiency decreases engineered into this car besides the weight increase, people will probably easily beat the EPA rating?

Some more food for thought. My friend and I both drove our i3 BMWS on a 64 mile trip to Santa Monica a couple weeks ago. He has a 22kWh 2016 Deka i3 Rex. I have a 22 kWh i3 BEV. Mostly 65mph freeway driving. I only got about.10 more mi/kWh. than him. 4.7mi/kWh vs his 4.6 mi/kWh. 21 miles of range remaining vs his 18 miles. Although I did occasionally use A/C..our efficiency was almost identical. So I think the 2017 Rex rating is really understated for some reason.Perhaps it is assuming some blended driving cycle that is different for 2017?

The window sticker says 97 miles but the story says 91 ?!?

Also, how is this getting a rating of 1 out of 10 for smog and fuel economy?

I want an explanation as well. The BMW i3 REX has the Worst rating for smog and greenhouse gas. Does the BMW i3 REX exhaust have a catalytic converter or is it unfiltered like a lawnmower engine?

I did a quick search. The BMW i3 REX has a catalytic converter.

Let’s hope the greenhouse gas and smog rating for the BMW i3 REX is a printing mistake and not the real rating numbers.

Looking at the fine print under the rating chart, it shows “This vehicle emits 29 grams of CO2 per mile”. At 29 grams CO2 per mile, this is a fraction of what a Toyota Prius emits.
For comparison, a 2017 toyota prius emits 171 grams per mile and has a California smog rating of 9 (out of 10).

The smog rating of 1 (the worse) has to be a mistake on the 2017 BMW i3 REX window sticker.

CO2 is completely unrelated to smog. VW’s lies for instance actually reduced CO2 output.

Wow! I would have never guessed that! I guess the Rex operation isn’t very clean. Good thing it is rarely used. We’ve only used the Rex on ours once since owning it.

Although the 2017 i3’s gross battery pack capacity is 52% greater (33.2 / 21.8) than for previous models, the usable battery pack capacity in only 45% greater (27.2 / 18.8) greater, so BMW is reserving larger unusable low- and high-charge-level buffers in the 2017 battery pack. The 2017 i3 BEV’s range increase is 41% (114 / 81), so maybe the slightly heavier weight of the 2017 model explains why the range increase is 4% less than the usable battery pack capacity increase.

However, there must be another explanation why the 2017 i3 REx’s range increase is only 35% (97 / 72), or 10% less than the usable battery pack capacity increase.

I would assume that there is always a tank reserve figured it, since it cannot be completely emptied while driving. (fluid movement). this was before not neccessary, since the tank wasn’t emptied ever. maybe the overall relative increase in usable tank size is therefore not that much? just a thought. Any auto mechanics here?
your fuel meter shows 0, but you can usually go for another while in most cars.

The i3 and the i3 Rex have the same everything except the Rex. I can’t see a reason why the Rex would result in you getting a more than 10% drop in electric range. My geuss is that the engine kicking in before the battery is flat is the problem. This, of course is only a problem for the test cycle because if you drove 180 miles you wouldn’t be stranded as you’d still have 17 miles of battery range left. That reality is a bit difficult to reflect in a test cycle that is probably less than 50 miles long with the last 150 miles being some strange blended mess of a calculation.

Epa revised fuel economy calculations for 2017 model year vehicles.
Even unchanged vehicles lost mpg from the 2016 rating to the 2017
Might be part of the 35mpg rating on the 2017 Rex

They must be leaving a larger buffer for Rex operation.

Still, that’s a 25 mile upgrade over the old version, which is nothing to laugh at considering many PHEVs don’t have that much range to start with. What surprises me most is the extra half gallon only gives 5 extra miles on REx power. I would have figured closer to 20 miles.

Is dead in the water they better hurry and sale what they can before Bolt obliterate the i3 as a better value for the money.

An interesting note about the smog rating.. It shows up as horrible on this sticker for gasoline only operation. But I found an older window sticker for last years model and it gives the Rex a 5 on smog. Still not great, but much better than a 1. I wonder why the difference?

If I was a potential i3 customer (I’m not), I’d go for the less expensive BEV. 114 miles is decent, The QC infrastructure is there now and will only get better, and the REx ‘limp home’ mode is not designed for marathon road trips anymore, so you’ll have to count on QC stations anyway.

I kind of agree.. But we just bought a used one recently and the battery range was simply not enough, so we opted for the Rex. But I think 114 miles is enough I could drop the Rex.

How’s the driving compared to your Volt?

Well, performance wise.. The Volt seems faster off the line and to 30mph. And the i3 seems faster from 30-60. THe numbers on paper seem to agree with that feeling as well.

The Volt definitely rides smoother. The i3 seems kind of bumpy on the freeway. We’ve only used the range extender once for about 10 miles. Mostly just to try it out. Seemed to work fine, but we didn’t try any extreme circumstances. Since this one has CCS and they’ve recently upgraded all of our fast chargers in Dallas/Ft.Worth to combo chargers we probably won’t use the Rex much.

Otherwise, it seems like a great car.

With added battery pack weight; did the gross carrying weight of the 2017 i3 change?
ie: wondering if any changes is load carrying capacity?

This is interesting. Previously RE was throttled down by around 30% comparing to the same engine used in scooters, most likely because of CO2 emissions (EURO5 for cars vs EURO3, soon 4, for bikes). Perhaps that is no longer required, at least in the USA.

Such RE could sustain the battery charge (even if at the last 5% level), so the difference between EU and US models would be almost eliminated. The EU model doesn’t need more powerful RE so they could just as well leave it restricted and keep emissions low.

Does the 2 cylinder motorcycle engine reduce the all electric range from 114 miles to 97 miles. This is unbelievable given the fact that Volt’s 18.4 KWh battery powers it for 53 miles even with a 4 cylinder engine.

BMW i3 has 33 KWh battery and its much lighter vehicle and should easily top 105 miles.

Looks like the company has restricted the range. I wish someone does some research to find this out.

9 out of 10 says the article has already answered everyones range questions…

“Why the lower improvements in range, especially on the gas extender? Perhaps the performance operation of the BMW i3, often criticized for being under-powered while driving on gas in the US (and sometimes leading to a lawsuit for its “Reduced Power Mode”), has been dialed up to better fit consumer demand.”

Still makes no sense, to me. If more kwh were reserved for REx mode assist, you’d still be able to run it down at 80mph, w/heat, etc. You’d still likely get to that problematic point. It would just be later during REx operation, and would still net the car that additional battery use.

This is a case where “real world” might tell a better tale.

It’s my understanding, the REX was designed to run at a constant RPM, which is why it’s getting the higher MPG that it gets. To generate more electricity and charge/extend at a faster rate, it’s possible they raised the constant RPM. This would charge/supply at a higher throughput of electricity, but it would consume a larger amount of gas in the same time period. Hence, the lower MPG for 2017.

only a fraction might be figured in by EPA in the testing, since the fuel gage will be at 0 before the tank is completely dry.

While the concept behind the I3 cars is solid, the overpriced I3 rex has already been thoroughly eclipsed by the excellent 2nd generation Volt on performance for the price and the I3 Bev will likewise get destroyed by the Model 3 and the Bolt.

BMW does however deserve alot of credit for making the older I3s battery upgradeable and if they would just get off their asses and build battery factories that push down the price of these upgrades we would have a winner here.

It’s still a BMW, though…You’re kind of saying BMW needs to get down the price of their one series ICE to the price of a ICE Cruze…And unlike the ICE versions, the i3 is the only “affordable” car to feature mostly carbon fiber, additionally the i3 has a footprint of an one series but the interior space of a three series so you actually are getting something tangible, CF/more room, for the premium price over the Volt…

Take the BMW badge off and none of those features would make a difference. It is overpriced for what it is and outmatched by the Volt, and soon by the Bolt.

The i3 REx now gets 35 MPG on premium, compared to 42 MPG on regular gas for the gen2 Volt. And the i3 REx has worse performance while weighing ~500lbs less.

I thought BMW was supposed to the expert in automotive engineering? GM’s engineers have put BMW under the table.

Can’t compare this Rex engine to the 2x larger Volt engine. This Rex engine is so tiny it sits in the empty spot next to the i3 motor as a modular serial generator. Much more simpler and lighter than the Volt setup. It was designed in concept to be used very occasionally. It can’t directly power the car mechanically. So you have all kinds of conversion losses: generator-electronics-battery-electronics-and finally to the motor. Of course its less efficient than directly coupling it.

Well, yes, I can compare the underpowered, inefficient REx (that cannot even provide cabin heat) in the i3 to the superior one in the Volt.

It’s just a very lopsided comparison.

Guys, a friend of mine has had his new i3 Rex since 1st September. He commutes a distance of 75 miles each way to our office.
His range has slowly extended over the course of the first week from 120 miles (battery only) to a whooping 159 miles.
The route is 90% motorway driving and he sets the dynamic cruse control at 80 miles per hr, allowing the car to slow automatically as required by traffic flow.
I think the new range is being dramatically understated by BMW….

I will get mine in the next week or so and will be able to re-confirm these results..

You can probably get double the EPA ratings on a 707hp Hellcat if you drive it efficiently…For 2017 they EPA adjusted their tests to become more “real world”…The average Joe doesn’t drive efficiently…

My guess is that they start the engine earlier. That way up hill driving wont be a problem. The engine will xontri ute and the battery will backit up longer. Sideeffect; shorter battery range, shorter gas range. Byt no powerloss.

This new version of the Rex will be a big test of the BEVx category for CARB.

There has long been a debate about what the root cause is of the US i3 losing power.

On one side of the debate is that the BEVx specifications are fatally flawed, and it is impossible to build a car to those specifications that is safe.

On the other side of the debate is that BMW didn’t put enough battery and too weak of a scooter motor in, and it was how they built their i3 Rex that was the problem, not the specifications.

Now we have an improved i3 Rex. If drivers report significantly less problems running out of power, then the BEVx classification will be vindicated. If even with these upgrades, the problem stays relatively unfixed, then CARB should revisit the BEVx classification, and figure out how to fix it.

There’s no controversy. You just don’t understand the issue and are conflating the CARB battery depletion requirement with the CARB gas range vs electric range requirement. The first causes the power issue and the latter causes the half gallon artificially lower gas tank.