Question about Range Extender

[BruceBecker]

Does anyone know if you can drive indefinitely (without hooking up to a charger) if you continue to fill up the gas tank every 80 miles when the gas is depleted?

Or do you have to charge the battery from a charger to some minimum level to resume driving again?

 

[Lolotte]

Hi,

As you can activate the Rex at around 80% of the battery for it not to discharge, I guess that it is possible to then refill the gas tank and keep your battery quite full and drive "indefinitely".

But the Rex version is not made for that purpose. It is mostly for range anxiety, and for ponctual "longer" trips that are less than 300 km or 180-190 miles...

 

[BruceBecker]

Understood - but having just spent 12 hours driving (and charging) my ActiveE to go the 200 miles from my summer house in Vermont back to Connecticut, i would definitely want the REX. This is a trip I only make about 6 times a year, but having the REX will make driving manageable. If I was just going to Vermont for a week or less I could take a BMW gas loaner, but the REX would be much more convenient and environmentally responsible.

With the ActiveE, returning from Vermont required that I spend 8 hours in aggregate charging at four different level 2 chargers along the way, which is barely tolerable, even though I planned the charging at meal times near nice restaurants. With the REX I will have to stop just once at a gas station which will add 5 minutes to the trip instead of 8 hours. Relative to getting a BMW gas loaner, I'll buying just 4 gallons of gas, rather than 10 gallons to make the round trip, not counting the gas I would use once I was there. I figure I'll save about 100 hours or my time and about 50 gallons of gas a year with the REX - so I will definitely get the REX.

The REX will also provide a back up to deal with the unavoidable situations where a charger I counted on using is not available or not functioning, or where charging is unexpectedly interrupted. (This happened with my ActiveE at least 4 times this past year, and can be very inconvenient - sometimes requiring finding a car rental on very short notice). Once, a garage attendant just decided to unplug the car after an hour of charging, without notice. So count me in for the REX!

 

[Lolotte]

The Rex version is made for you then !

 

[ultraturtle]

I'll tag on to this question to ask if there is any update on whether or not BMW will include the ability to switch to REx (below 80% SOC) in models destined for the USA. Tom mentioned some uncertainty about this in his blog, so I know he is on top of it. This issue might matter to more of us than you might first think...

At some point during ownership, a great many of us will need to "ferry" the car a significant distance for reasons like seasonal migration, job moves, or, even (as in my case), initial purchase. I'll most likely be purchasing my i3 in New Jersey and will need to drive it about 900 miles home to Atlanta. Making an optimistic assumption that the i3 will be capable of 80 miles range on electricity and 70 miles on gasoline at expressway speeds, there would be a significant advantage in both time savings and stress-reduction should we Yanks get the same capability as our European buddies. Consider two scenarios that get you home with a reserve of 20 mile range remaining:

With the ability to switch to REx at 80% SOC, the trip takes 14:41 with a comfortable reserve of 64 miles of EV the whole way, diminishing in the last 44 miles home to pull in the driveway with 20 miles of EV range remaining:

Driving time @70mph: 12 hr 51 min
Refueling stops @ 10 min every 70 mi (11 stops): 1 hr 50 min
Total Time: 14 hr 41 min

Initial Battery Power Distance: 16 mi (to get to 80% charge)
Gas Power Distance 840 mi
Final Battery Power Distance: 44 mi


If that capability is not included, the trip would be 50 minutes longer, assuming a nail-biting reserve of only 20 miles of gasoline engine range:

Driving time @70mph: 12 hr 51 min
Refueling stops @ 10 min every 50 mi (16 stops): 2 hr 40 min (this keeps 20 miles of gas range in reserve)
Total Time: 15 hr 31 min

Initial Battery Power Distance: 80 mi (to depletion)
Gas Power Distance 820 mi


The ability to use easy to find, quick to refuel gas for long trips while keeping hard to find, slow to refuel electricity in reserve is very important to those of us who will need to occasionally make longer trips like this.

 

[Ed B]

A NJ purchase to avoid sales tax?

 

[ChrisC]

ultraturtle, I'm in Atlanta too (but raised in NJ ). Why do you plan to buy in NJ?

I haven't committed to the i3 yet, as this time I really must get an in-person look at the car before I do so, but I've put down a (refundable) deposit with a dealer in the Atlanta area.

Regarding your question, there's no new news about the purported "hold mode" (a la the Chevy Volt). I expect we'll have a wave of news over the next week as the Frankfurt show gets rolling.

I must say, your gas / mileage calculations seem silly to me. Regardless of whether there's a hold mode or not, you're going to use up the electric range at the beginning or at the end of the trip. What difference does it make?

Personally, based on my 3 years of experience owning the Chevy Volt, I put it in gas mode as soon as we hit the highway, and come out of it (back to EV mode) every time we leave the highway (e.g. for gas fueling stops or detours). Then once we are within striking distance of our destination I come out of hold mode and drive electric the rest of the way. I've done it many times.

 

[ultraturtle]

Why do you plan to buy in NJ?

I misunderstood the term "Launch City" to mean those cities where select dealers will first be selling the i3. This was the case with my PiP. It was not available in Georgia, and I had to fly to the Northeast to pick it up and drive it home. Tom informed me that this may not be the case with the i3 and that it may be available in Georgia at or near the same time it is available in New Jersey, so I may not have to make the trip after all.

Regardless of whether there's a hold mode or not, you're going to use up the electric range at the beginning or at the end of the trip. What difference does it make?

The difference is the distance between refueling stops, the number of refueling stops, the total time for the trip and the range you can hold in reserve. With the "hold" switch (or EV/HV switch, in PiP parlance) one can make the above theoretical 900 mile trip in 14 hours, 41 minutes with 11 fuel stops (every 70 miles - to gas depletion) and maintain an EV reserve range of 64 miles the whole way. Without it, in order to maintain a minimum gas reserve range of 20 miles, one would need to make 16 refueling stops (every 50 miles), which would take 50 minutes longer. Takeaway is that the ability to use easy to find, quick to refuel gas for long trips while keeping hard to find, slow to refuel electricity in reserve on long trip both makes the trip quicker and reduces the stress of repeatedly driving to a nearly empty fuel state.

On another note, I assume you know that the REx is a very expensive option for Georgia residents, as it makes the i3 ineligible for the $5,000 state tax credit?

 

[ChrisC]

This was the case with my PiP. It was not available in Georgia, and I had to fly to the Northeast to pick it up and drive it home. Tom informed me that this may not be the case with the i3 and that it may be available in Georgia at or near the same time it is available in New Jersey, so I may not have to make the trip after all.

Yeah, I did the same with my Chevy Volt ( www.FirstVoltInGeorgia.com ). I'll do it again if I have to, but it's not looking like we'll need to this time around with the i3, as you said.

Without it, in order to maintain a minimum gas reserve range of 20 miles, one would need to make 16 refueling stops (every 50 miles), which would take 50 minutes longer.

Ah, I see, you want to maintain a range reserve, either EV or REx. Gotcha.

On another note, I assume you know that the REx is a very expensive option for Georgia residents, as it makes the i3 ineligible for the $5,000 state tax credit?

Yup. It's effectively a $9000 option for us in Georgia. Personally I've gone back on forth on this over the last month:
1. I must have REx, until at least one SAE CCS station exists in Atlanta. Once a year or so I'll lose power at the house (storms etc.) and after a couple days of that I'm in tough situation. DCFC somewhere gets me over that.
... but then I changed my mind ...
2. Boy, $9000 is a lot. Maybe I'll just get a pure EV i3 and cross my fingers on the eventual CCS station
... but then I changed my mind ...
3. Dang it, I really want that REx, in fact I want the car loaded with options. Splurge!
... further ...
4. After about a year I expect that the Georgia bureaucrats will have warmed up to the i3 REx and may allow it to qualify for the tax credit after all, just like CA allows it. This is exactly what happened with the Volt and HOV lane access -- it took us six months but they did eventually let it through. Then they would typically make it retroactive. This is HUGE speculation --- $5000 of specualtion. I'm considering just taking that risk with the i3 REx.

And so forth. Apparently, when it comes to EVs, I really like to be on the bleeding edge

I do expect CCS coverage to enable roadtrips soon enough, but at this point I kind of like having the REx option. It makes my presentations with EV newbies go smoother. I see i3 REx as Volt 2.0 .

 

[AndrewDebbie]

Once a year or so I'll lose power at the house (storms etc.) and after a couple days of that I'm in tough situation.

Only once a year? When we lived inside the perimeter we lost power at least once a month. Squirrels, trees, lighting, wind, large trucks driving into power lines. . .

$9,000 for a Range Extender? You can get a 20kW generator for about half that. You'd be able to run your entire house and charge the car.

An 8kW generator would be enough to charge the car and run few essentials.

 

[TomMoloughney]

Chris: I'm almost in the same position as you. I'm toiling over the REx decision. Here in NJ, zero emission vehicles are tax exempt so that means the Rex will cost me the $3,850 and then I'l have to pay 7% sales tax on the entire car, so add another $3,400 or so. It really is a $7,200 to $7,300 option for me.

It's tough because I know I don't need it. I've lived for 4 years with EV's that have similar range but it would be nice to know I can use it for the occasional 220 mile journey to my in-laws or that I never have to really think about where I'm going on a day that I'm driving further than I usually do. It really hasn't been that much of a hassle, just a minor inconvenience every now and then. Still it would be nice to never have to even think about it.

I think I'll probably go back and forth a few times before I buy. One factor for me is residual value though. I'll be buying because I drive too many miles to lease. I do believe the range extender option will dramatically increase the resale value. You may even get back nearly as much as the option originally costs (but not the extra sales tax money it will cost me).

 

[Mike74jcw]

I'm also on the fence about the Rex. I think it will be a good, although pricey, option but then again BMW is said to be making loaners available to i3 owners for longer trips. Either way sounds good to me, but I like the thought of being able to drive much farther with the Rex.

My LEAF takes me to most places (local) that I want go, however, I do like to go to D.C. (200 miles RT) and points north, to see my family in North Carolina (300 miles RT), to go to places in the mountains (120-180 miles RT), and to the beach.....places it can't go without lengthy stays somewhere.

 

[Plug]

BMW is said to be making loaners available to i3 owners for longer trips.

They are but in the UK it's costing £480 per annum (about $750) to be able to do that and as far as I can tell they haven't yet said how many days of loaners that includes so the jury is still out on whether that's going to be a worthwhile deal or not.

http://bmwelectricpackages.atosb2b.com/packages#packages-compare-tabs

 

[AndrewDebbie]

I was told the base level Access has enough points for a week in a 1 series or a weekend in a Z4. That could be wrong.
Renting Luxury cars is expensive. BMW's prices are in line with rates from other companies. BMW will sell additional points but I haven't seen any details. The price of the additional points is what will make the program a good deal or crazy expensive.

I also don't know any details about how they get the cars to customers. Is it from a BMW-i dealer, any BMW dealer or do they deliver the cars to customers?


The range extender is only good for about 60 miles. With it realistic range is perhaps 150 miles with careful driving. Not enough for those long road trips but it will get you home if the car uses a bit more charge than you expected.

Manchester Airport is 105 miles from our house. There is one big range reducing hill along the way. Too far to make it on a single charge, but we could do the trip with the range extender. Getting back would be a problem. There aren't any rapid chargers. There are a couple of fast chargers, but that would add 3 or 4 hours to the trip and we'd still have to stop for petrol too.

 

[TomMoloughney]

AndrewDebbie: "The range extender is only good for about 60 miles. With it realistic range is perhaps 150 miles with careful driving. Not enough for those long road trips but it will get you home if the car uses a bit more charge than you expected."

You could always just stop for gas and continue along.

 

[Parker]

If you know you are embarking on a long journey ...... just hit the Rex shortcut button when the battery reaches 80% and as long as you keep filling up with petrol you'll keep going (on those occasions I'd probably take a small Jerrycan as well). OK your EV turns into a 40mpg hatchback but for the odd occasions when you need to travel further I'd rather do that than go through the faff of renting a car.

I'm still torn over the Rapid Port option though as in AndrewDebbie Manchester Airport run scenario it would be nice once at the Airport to Rapid charge and get a lot of the way home on Electric ....... rather than do well over 50% of the journey using petrol HOWEVER there seems to be lots of promises regarding Rapid Charger installs - but no action as yet.

If I could see a plan of anticipated Rapid Chargers available in 5 years (that the i3 could use!) that would be really useful.

It would have been really great if all the 40+ BMW "i" dealers had 24hr accessible Rapid (not Fast) Chargers as originally talked about - the UK would then be just about covered. Then convert a couple of Leaf fast Chargers at Motorway service stations and Bobs Your Uncle no need for Rex in the UK

 

[AndrewDebbie]

Stopping every 40 to 50 minutes to refill the REx will be annoying.

There aren't any Rapid chargers in North Wales and I doubt there will be any soon. I'm tempted to say no to REx and use the money to pay for the occasional rental car.


Whatever we do, it will be the wrong choice

 

[TomMoloughney]

Stopping every 40 to 50 minutes to refill the REx will be annoying.

There aren't any Rapid chargers in North Wales and I doubt there will be any soon. I'm tempted to say no to REx and use the money to pay for the occasional rental car.


Whatever we do, it will be the wrong choice

The thing is, if you believe you need to use this car to frequently drive the car very far (like 300+ miles) then it might not be the right choice of car for you. You'll likely only have to stop once in a 220-230 mi drive and that's usually about when I'd stop for a brief brake if I were driving a gas car that far. How frequently do you thing you drive further than that? If you are setting out for a 500 mile trip, use a different vehicle if stopping once an hour is bothersome. Choose the right tool for the job I say.

 

[AndrewDebbie]

You'll likely only have to stop once in a 220-230 mi drive and that's usually about when I'd stop for a brief brake if I were driving a gas car that far.

We both agree the i3 is not a good choice for driving long distances. With a decent destination charging infrastructure, REx turns an 80 mile car into a 120 mile car. Without it I don't think the Range Extender is much help.

BMW says real range on battery is 80 to 100 miles and the Range Extender is good for 60. Gas stations are never spaced exactly where they need to be either. The range extender comes on when the battery is down to 20%. The car will be out of fuel and back on battery after about 120 or 130 miles. Hills, cold weather and driving at 70mph eat up range. Winter 200 mile trips in most places will see all three.

I'd say stopping two or even three times for fuel to get 220-230 miles is more likely. If there is not be charging at the destination, I'd be hunting for fuel every 40 miles on the way back.


=====

Without the Range Extender but with Cold Weather Prep and Heat Pump options:


Our daily commute is 40 miles round trip. The closest movie theatre is 60 miles round trip. Both are comfortably within the worst case winter range.

Chester is 73 miles, but has destination charging.
Liverpool also has destination charging. But at 83 miles and Rhuallt Hill along the way Liverpool is probably out of range unless we stop to charge en-route. Doable but charging options are limited.

REx puts Liverpool in the comfort zone.

Anything farther and we'd have to a rent a car or take the train.

I'd probably spring for the Range Extender if the i3 could make the round trip to Manchester Airport. But it can't without charging at the airport.


( Put Penmon LL58, United Kingdom into google maps and Zoom out a bit if you are curious )

 

[TomMoloughney]

You'll likely only have to stop once in a 220-230 mi drive and that's usually about when I'd stop for a brief brake if I were driving a gas car that far.

We both agree the i3 is not a good choice for driving long distances. With a decent destination charging infrastructure, REx turns an 80 mile car into a 120 mile car. Without it I don't think the Range Extender is much help.

BMW says real range on battery is 80 to 100 miles and the Range Extender is good for 60. Gas stations are never spaced exactly where they need to be either. The range extender comes on when the battery is down to 20%. The car will be out of fuel and back on battery after about 120 or 130 miles. Hills, cold weather and driving at 70mph eat up range. Winter 200 mile trips in most places will see all three.

I'd say stopping two or even three times for fuel to get 220-230 miles is more likely. If there is not be charging at the destination, I'd be hunting for fuel every 40 miles on the way back.


=====

Without the Range Extender but with Cold Weather Prep and Heat Pump options:


Our daily commute is 40 miles round trip. The closest movie theatre is 60 miles round trip. Both are comfortably within the worst case winter range.

Chester is 73 miles, but has destination charging.
Liverpool also has destination charging. But at 83 miles and Rhuallt Hill along the way Liverpool is probably out of range unless we stop to charge en-route. Doable but charging options are limited.

REx puts Liverpool in the comfort zone.

Anything farther and we'd have to a rent a car or take the train.

I'd probably spring for the Range Extender if the i3 could make the round trip to Manchester Airport. But it can't without charging at the airport.


( Put Penmon LL58, United Kingdom into google maps and Zoom out a bit if you are curious )

Good points. Do you have any documentation or links about the 60 mile REx range? Everything I've read and BMW's press release says it will extend the range 85 - 90 miles. Granted that's probably optimal range which us mortals never get but 60 miles for a 2.4gal tank seems pretty low, no? Operating strictly as a generator I would expect at least 35 to 40mpg. Even the Volt with a much bigger engine pushing a much heavier vehicle gets 35mpg.