What is a normal realistic range on an i3 Rex

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andya

Member
Joined
Mar 4, 2018
Messages
10
Hi guys I am looking to get an i3S or a normal i3 as my next company car in the UK but what is a realistic range that I would get from the car with a Rex on it as I have no idea I am under the impression it is about 80 miles on the Rex and maybe 125 miles on the electric giving a daily range of around 200 miles does that sound right? Mine would be the latest 2018 model and out of interest are they bringing out an even bigger battery version later this year?

Thanks
 
That's sort of like asking, how high is up?

FWIW, I think that the US EPA estimates on range are more realistic than the Euro testing scheme. As a community, people have been averaging about 4-miles/kw, but some barely get much over 2, and others regularly get over 5. It all depends on where and how you drive. You can look on the EPA website to see what the USA testing cycle lists as a comparison to the EURO testing (US ends up being about 30% less, but closer to reality for most people). There can be a huge difference based on the weather, mostly the temperature, and your speeds traveled. Drag goes up quite a bit as you raise the overall speed. This does affect your overall range. Keep in mind that the car was optimized for city driving and commuting. THeir years of testing in EVs prior to releasing the i3 showed the average commute was 34-miles or about 55km. It was optimized for that and the REx was added as a comfort factor, but wasn't really desired at all, but the marketing people felt it would help in the acceptance of the vehicle. IMHO, if you regularly will depend on the REx to get you there and back again, it may not be the right vehicle for you. If you can recharge at your destination, and will only use the REx as an emergency backup, it makes sense to me. While running on the REx, you'll only be getting about 34-miles/US gallon...not fantastic, but not horrible, either.
 
What Jim said. My experience is 110 in the summer and about 80 when the weather drops below freezing. All this is battery range, before the REx comes on. It's rumored that the 2019 models will have a bigger battery but I haven't seen an official announcement.

Another data point:
I just got back from an 80 mile road trip on the interstate. Starting outside temp was 35 degrees F and it was windy. I used eco mode the whole way, driving mostly at 70-75 miles per hour. The car used 80% of it's battery capacity in those 80 miles. The "meter" recorded 3.4 miles/kWhr, which I thought was low.
 
I have a 2017 REX

Getting about 85+ in cold weather.
And 120+ in the Summer.

And, I have the REX just in case.
I have never needed the REX unit.

Car is doing better, since the last software update.
They updated the software, when they fixed the front airbag situation.

Doing great.
 
I just checked my guessometer.

Highest, I have ever seen.

133 miles batteries.
86 REX unit

It is almost 70 degrees here.
Very nice

Will not last
 
When a new software build is installed, it resets the history file, and the range goes to the default value...IOW, depending on how you drive it, it will likely return to your 'normal' values after awhile.
 
Milam said:
I have a 2017 REX

Getting about 85+ in cold weather.
And 120+ in the Summer.

And, I have the REX just in case.
I have never needed the REX unit.

Car is doing better, since the last software update.
They updated the software, when they fixed the front airbag situation.

Doing great.


That sounds great wow there is a big difference in range in cold and warm weather I will be getting the latest model but I am still unsure about whether it will work for me I am a sales rep covering the North East of England and I do around 25,000 miles a year.

I want it to work as I have to get my BIK income tax down as when you work out what you're paying it is horrifying and with the BIK rates change in April 2020 having a car with a quoted range of 124 miles will really help, I do a Newcastle trip every two weeks which is a 220 mile round trip so in cold weather 85 miles isn't great but I won't mind just using the Rex but is it ok doing that?

Some work days I might do anything form 20 miles to 120 miles so it would work a lot of the time but am I mad thinking about getting one if I do 25,000 miles a year?

I need a car in the lowest BIK bracket and I love the fact that the i3 has a Rex on it why don't other manufacturers do this as I can't just have a pure electric car.
 
Yes it's ok to "just use the REx" on long trips. People do it all the time. I assume you're in the UK which means your i3 will already be coded so that you can turn the REx on manually below 75% SOC. You need to do that if you're going to use the REx because the generator won't keep up with battery drain unless you go < about 65 miles per hour.
 
theothertom said:
Yes it's ok to "just use the REx" on long trips. People do it all the time. I assume you're in the UK which means your i3 will already be coded so that you can turn the REx on manually below 75% SOC. You need to do that if you're going to use the REx because the generator won't keep up with battery drain unless you go < about 65 miles per hour.

Thanks for that and yes I am in the UK I do a fair bit on the M1 and A1 plus a lot of driving into market towns what do you mean turn in on manually below 75% sorry I am new to EV cars so I am not very familiar with all this do I use the Rex when the electric charge drops to 75% is that what you're saying.

I really want this car to work for me as I am sick of paying as much per month for my company car as I do currently and with the new BIK rates in April 2020 the i3 drops to 5% which will save me a lot of money over three years, I know I will just have to get used to managing the car and how it works but I do love the car and will test drive one soon hopefully the company can get a decent lease deal on it.
 
The REx was designed to be a last minute, keep me going device. But, say you were planning on going into central London with its fees, and wanted to ensure you had enough battery capacity to run around while there, you would want to use the REx to try to maintain your battery capacity until you got there...so, while the REx will come on automatically if your charge level gets low enough, they provide a means to turn it on prematurely, as long as your battery is below 75% (that's so that there's enough capacity to allow the thing to run long enough to warm up and not overcharge the batteries). If you let the battery capacity get too low, the car will start to go into self preservation mode, shutting down some things (like lowering the max acceleration and speed, minimizing the HVAC capacity), and if you continue to exceed the capacity of the REx output and lower the battery capacity, it will eventually shut down. In general, it has enough capacity to keep you going if your speed doesn't exceed about 65mph unless you've got the heat on max or climbing up a long grade.

When running on the REx, your MPG is only about 34 (US) mpg. Averaged over the EV only mode, it's still high, but if you need to use the REx, it will not be that high. Also note, the UK does have a reasonable amount of DC fast chargers out there, so if you can wait about 30-minutes or so when the battery is low, you can achieve at least an 80% charge or so depending on the temperatures and overall situation. That's assuming the thing works when you get there.

The car is fun to drive, and people do take them on long trips, but once your battery is down, refilling the REx once an hour or so can get old. It works.

The REx is s serial hybrid...all of the other hybrids out there right now are parallel hybrids. That means that the motor only drives the generator, never drives the wheels directly. All of the others can drive the wheels and have an electric motor that can also drive them, sometimes at the same time...that does not happen to the REx. Consider that it's only about a 34Hp motor...think of a car with only a 34Hp motor...once the batteries are low, that's all you have to keep you going...it's not much. Luckily, just cruising, the car doesn't need all that much, and it can maintain.
 
jadnashuanh said:
The REx was designed to be a last minute, keep me going device. But, say you were planning on going into central London with its fees, and wanted to ensure you had enough battery capacity to run around while there, you would want to use the REx to try to maintain your battery capacity until you got there...so, while the REx will come on automatically if your charge level gets low enough, they provide a means to turn it on prematurely, as long as your battery is below 75% (that's so that there's enough capacity to allow the thing to run long enough to warm up and not overcharge the batteries). If you let the battery capacity get too low, the car will start to go into self preservation mode, shutting down some things (like lowering the max acceleration and speed, minimizing the HVAC capacity), and if you continue to exceed the capacity of the REx output and lower the battery capacity, it will eventually shut down. In general, it has enough capacity to keep you going if your speed doesn't exceed about 65mph unless you've got the heat on max or climbing up a long grade.

When running on the REx, your MPG is only about 34 (US) mpg. Averaged over the EV only mode, it's still high, but if you need to use the REx, it will not be that high. Also note, the UK does have a reasonable amount of DC fast chargers out there, so if you can wait about 30-minutes or so when the battery is low, you can achieve at least an 80% charge or so depending on the temperatures and overall situation. That's assuming the thing works when you get there.

The car is fun to drive, and people do take them on long trips, but once your battery is down, refilling the REx once an hour or so can get old. It works.

The REx is s serial hybrid...all of the other hybrids out there right now are parallel hybrids. That means that the motor only drives the generator, never drives the wheels directly. All of the others can drive the wheels and have an electric motor that can also drive them, sometimes at the same time...that does not happen to the REx. Consider that it's only about a 34Hp motor...think of a car with only a 34Hp motor...once the batteries are low, that's all you have to keep you going...it's not much. Luckily, just cruising, the car doesn't need all that much, and it can maintain.

Thanks so much for,that reply :) I do about 25,000 miles a year with my job but IF my company can get the numbers to work on the i3 then I will get one and I know it will be tricky to manage how the car works as it will be my first one but I just have to save paying so much BIK tax as I never use my car for private miles so I do feel aggrieved that they hammer me for tax when it is a tool to do my job.

A lot of my journeys will be anything from 20 miles to maybe 150 miles but every two weeks I go to Newcastle which is a 220 round trip when I have done my calls I get out of the city and stop at a services to have my sandwich and there are two fast chargers there so maybe that might work :) I do a lot of motorway and A road cruising as well.

Over three years it will save me around £6,800 which is massive so I am thinking the i3 Rex is the only option I have as it has the Rex on it which means I can always get home :)
 
AT highway speeds, you've got about an hour or so of petrol in the tank. If you can afford the time, at least some of the service stations along the motorway also have CCS charging stations, but filling the fuel tank will be faster. As you can tell from that scenario, the car was designed for running around the city, not cross-country trips. Like many things, though, while not as convenient, you can make do. Generally, your economy will come from charging the vehicle, not from using petrol.
 
To bump the post, but did you get an i3 Andya? If so how are you finding it. Am considering it but with a 120m round commute I'm concerned I may being too optimistic!
 
My 2018 i3 REX has been getting great range estimates based on recent summer driving with a combination of city/hwy trips. This morning the connected app. is showing an estimated electric range of 139 miles + 80 of REX. Quite surprised and impressed.

I've been using the Eco-mode for the most part and gradual acceleration and deceleration with the regenerative breaking. Will see how it does in it's first colder months this winter and provide updates.
 
brucie said:
I guess what really concerns me is how much use of Aircon/Heating , lights and Sound System have an impact.
The lights and sound system have a negligible effect on range.

An i3 REx uses a resistance heater for cabin heating whereas a BEV uses a heat pump backed up by a resistance heater when low ambient temperatures make a heat pump inefficient. So using the heater in a REx in particular has a significant effect on range. It's not possible to state exactly the effect because it depends on ambient temperature.

The use of aircon doesn't reduce range as much as cabin heating because the difference between ambient and comfortable cabin temperatures can be greater in cold weather compared with warm weather. This is especially true for a REx because it uses a more efficient compressor for aircon but a less efficient resistance heater for cabin heating.
 
Also, BMW has said that running with the windows open above 25mph uses more energy because of induced drag than running the a/c, so you don't have to boil in the summer. If you can live with the windows closed and the a/c off, yes, that will increase the range. Preconditioning while plugged in also will certainly help in both the winter and the summer as, for the most part, the power is not coming from the batteries.

Cold DOES make, a potentially significant impact on battery range (not as much when the REx is running). It's more of an impact on the REx if you need heat. The use of the seat heater can let you minimize the cabin temperature while still being comfortable, though.

Your worst scenario will be short trips with enough time for the cabin to return to ambient which may impact the battery if it's cold, and the amount of energy it takes to re-condition the cabin. It's better on a longer trip where conditioning only occurs once than lots of short hops with a long time in between. The battery is fairly dense, so once warmed up, it does take a while to cool off...setting a departure time is your friend in those circumstances (assuming you're plugged in). Click the cabin conditioning option while you're at it.

Last winter, I saw some temperatures of -10F and daytime temperatures may not have gotten above zero F, and the battery range wasn't great...maybe lost as much as 40% (usually less). But, the range comes back as the temperature warms up...today, it said 84-miles when I got in, about what it did 4-years ago (original BEV battery size). I essentially always run in comfort mode and my daily uses don't stress my BEV so no desire to run in one of the Eco modes. IF I really need to go further, I take my ICE unless there's a handy EVSE at my destination (doesn't happen often around here, though).
 
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