i3 Electric Car Review

by @edent | , , | 8 comments | Read ~2,440 times.

A few months ago, I blogged about how cost efficient electric cars are. Last week I took delivery of a BMW i3 REX - so here's a quick review of the vehicle. A warning, I'm a grumpy, demanding, sod. I really like the car - but that doesn't blind me to its flaws.

But first, and brief diversion into PHYSICS and MATHS!


Imagine a kilogram weight (1Kg) sat on an ice rink. You want to push the object 1 metre. The energy you require to accomplish this is 1 Joule.

If you want to impart 1 Joule per second, that will take 1 Watt (1W).

Imagine a 100 Watt lightbulb - the old incandescent type - every second it is using 100 Watts. Run it for an hour and it has used 100 Watt hours (100Wh). Run it for 10 hours, and it will have used 1,000 Watt hours, or 1kWh.

Ok? Onwards!


My previous car - a Toyota Yaris Hybrid - had a 35 litre fuel tank which could take me around 420 miles.

420 miles / 35 litres = 12 MPL

1 mile per UK gallon = 0.22 miles per litre (Americans - our gallons are bigger than your gallons!)

12 / .22 = 55MPG

Based on my driving style and cost of fuel, we can work out the cost-per-mile.

To fill up a tank:

35 litres * £1.26 = £44

Here's how much fuel costs to drive per mile:

£44 / 420 miles = £0.105/mile.

(Fuel costs in the UK have fallen recently, but £1.26 was the average over the last 3 years.)

How does this compare to an electric car? I'm with Ovo Energy and my electricity costs roughly £0.13 per kWh.

The i3 has a usable battery of 18.8kWh. Therefore, the total cost to filling up is

18.8 kWh * £0.13 = £2.45

That's a cheap charge! But how far does it get us?

Range on an i3 is a slightly confusing affair. If I'm pootling around town and don't have any heating or air-conditioning on, it will happily do around 100 miles.

In the dead of winter, with the heat on full blast, driving up hill all both ways, and with your foot constantly on the pedal, it looks like it will do about 50 miles.

For all of the journeys I've done, it looks like around 88 miles per full charge. Let's call that 80 miles for simplicity.

£2.45 / 80 miles = £0.03 per mile

Yup, a thruppenny bit per mile when charging from a socket in a garage. Costs elsewhere may be higher - more on that later.

This tallies with the stats generated by the app.

i3 Stats-fs8

I get 4.3 miles per kWh.

4.3 miles * 18.8 kWh = 80 miles per full charge

When I'm working from home, I can charge the car directly off my solar panels.

So, on a good day, I can charge my car for free - then rest smug in realisation that I'm literally...

Ok! On to the review!


Let's get this out of the way first, the i3 has shockingly poor software. Car manufacturers are very good at hardware, but the usability and functionality of the software are at least a decade behine the state-of-the-art. Many of the problems with this otherwise brilliant car could be rectified with a software update. Whether BMW has the guts to radically improve its offering is another matter.

There is an app which comes with the car (Android and iOS) - again, it's poorly constructed and only offers limited access to some of the essential features of the car. More on that later.

The second thing to mention is the cost. This is a company car, so the real cost is obscured from me. It's a pricey car and BMW are incredibly stingy with what they include with it. If you want some of the smart driving features - and they are essential - you have to pay for an upgraded interior. Why? Because that's the only way to get the upgraded steering wheel!

One of the joys of the i3 is that it has a "Rapid Charge" port - pump pure DC into your car for a charge in 30 minutes. That's an extra cost.

Want to charge at public port? BMW only supply a regular 3 pin charging plug. They'll sell you the appropriate cable for £160. Or you can buy a third party cable for £130.

The base model does come with GPS maps (updated quarterly) and basic remote control connectivity - but if you want web access, traffic reports, or anything else - be prepared to pay. Personally, I just use Google Maps on my phone - they're more usable and accurate than BMW's offering.

Finally, lights. By default, the car comes with power-hungry halogen headlights. Want efficient LEDs? Another six-hundred quid, guvnor! Ok, so efficient LEDs only add about 1% to the range, but surely that's the sort of thing which should be built in as standard?

Overall, it makes buying the car a frustrating and expensive experience.

Set Up

Ok, so you've got your car. Time to crack open the manual! I really wouldn't bother. BMW have put the least amount of effort into this as possible. A dull, black and white tome which shows a left-hand-drive model despite the UK being a right-hand-drive country. The index at the back is simply wrong, sending you on a wild-goose chase to pages which bear no relevance to the topic at hand. Your best bet is doing an Internet search for your question and hoping someone else has figured it out first.

I think Kathy Sierra said it best:
How We Treat Customers - Kathy Sierra

Why doesn't the manual look as good as the brochure? Why has all the effort gone into convincing me to buy this car - but no effort in making my first experience with it delightful?

Ah well. It's reasonably obvious how everything works. If you're the sort of person who enjoys systematically pressing every button and creating a mental map of where every function is, you'll be fine. I imagine everyone else just leaves the defaults as they are and gets frustrated that they can't see the time on the dashboard (press the "DC" button repeatedly) or turn off the traffic reports (not controlled in a "Radio" settings, but by double tapping the aerial button near the volume control).

A word on that volume control, and the heating control, they're on the left hand side. Yup! This car was designed for those who drive on the wrong side of the road! Most modern vehicles integrate an ambidextrous design which can be used by LHD or RHD drivers. Not this car! I'm a long-limbed guy, and I find some of the more common dials just a little too far away to be comfortable.

This does have the side effect of making the Bluetooth "Skip Track" buttons more reachable. Because the jog-dial on the steering wheel only works with the radio - it doesn't work with Bluetooth devices. Because software is hard.

While I'm on the subject of Bluetooth - it connects just fine to my phone. I can stream audio and make handsfree phone calls. BMW are keen to sell you an extra Bluetooth option which, as far as I can tell, just allows you to connect multiple phones and send basic emails from your dashboard. I avoided that. Of note, there are two "cigar" charging ports in the car. One just under the dash and one in the centre console. So you can plug in and charge multiple devices. There's also a standard USB port if you want to play MP3s that way.

The standard sound option is perfect. You can pay extra (of course) for better speakers - but all the music and podcasts I've played sound great. Because there's no engine noise, you don't need the sound up quite so high.

You get FM and DAB radio - although the interface for accessing them is quite confusing. There's also a hidden AM radio which you can unlock if you're willing to hack your car. Apparently the engine interferes with weak AM signals, which is why it is disabled by default.

I've mentioned on this blog before about OBD ports on cars. The i3's is under the steering wheel and to the left. Here's a picture with a Bluetooth OBD dongle plugged in.
i3 OBD port
I've not managed to get the port to do anything interesting... yet!


It's clear that BMW aren't app designers. What's less clear is why they refuse to open up their APIs to let real developers create innovative and useful services.

The app forces its own PIN lock. You may protect your phone will all manner of biometric security features, but BMW insist on having yet another PIN. If you flip out of the app and then straight back, you need to input the PIN again. Mine's 1234.

The thing is... there's such a limited range of things to do with the app, it doesn't really warrant extra protection. You can...

  • See stats about your driving style.
  • See charge and battery status.
  • See if windows and doors are locked.
  • See the car's location and send destinations to the GPS.
  • Toggle some basic remote control features (lock, unlock, flash headlights)
  • Tell the car when to charge and when to precondition the cabin.

That's it. Here's a quick list of things which would be actually useful. I thought of them after playing with the app for 10 minutes.

  • Receive push notifications when the battery is full.
  • Push notifications if the battery stops charging unexpectedly. (eg, someone has unplugged it.)
  • Start and stop charging.
  • Set the cabin temperature. The current preconditioning function only works with the temperature you last set. So if you drove to work in the cold, but you're parked in a sun trap, you currently can't switch on the AC.
  • Shut the windows via remote.
  • Perhaps video stream from the front & rear cameras.
  • Deploy or collapse the wing mirrors.
  • Tweak any of the software settings.

I'm sure there's a couple of dozen useful things that it could do - it just feels like BMW has done the bare minimum needed to make the car qualify as "smart".

You can read the i3's API documentation - but you can't do anything with it ?.

The Drive

It's fun - there's no doubt about it. The electric engine has instant torque, so you really get thrown back in your seat when you hammer it. For overtaking it's amazing. Incredibly responsive, the lightest touch will have it respond to your desires. The turning circle is amazingly small - you don't need to a 3 point turn, just yank the wheel all the way.

There's an electronic handbrake - you just press a button and it engages. You don't even need to disengage it manually - just start driving. Excellent!

Adaptive cruise control is magic - the car will keep its distance from the car in front of you. If they slow down, the cruise control automagically brakes. Brilliant!

The enhanced features like auto-parallel-parking are uncanny - hold down a button and the car takes over power and steering. Similarly, when using Traffic Jam Assist the car will drive itself - accelerating up to 35 MPH and sticking to its assigned lane. Actual witchcraft!

Of course, the car is silent when driving. Make sure you wind down your windows so you can yell at oblivious pedestrians. The car will also automatically detect "obstacles" like people and bicycles. I've not had an near-misses, so can't comment on how well that feature works.

Because the engine is silent, you really notice the road noise - that's not a criticism, just be aware that you won't be in a silent bubble if you're going down the motorway.

The i3 uses regenerative braking. As you slow down, the battery begins to charge - nifty! This means that if you take your foot off the accelerator, the car acts as if you've tapped the brakes. It takes a little getting used to, but after a week I think I've mastered the art of one-footed-driving. It's a pleasant experience

I only have three criticisms of the drive:

  1. The suspension is a bit hard. It really does pick up a lot of the imperfections in the road. It's bumpy but not uncomfortable.
  2. The mirror is a little small. This might be because I'm used to this giant Android Dashcam. It's perfectly serviceable - just a little cramped.
  3. The software...

*sigh* Back to this point again. The adaptive cruise control has a habit of shutting off when it can't see the road ahead. That's fair enough - but it seems particularly badly affected by the sun low in the horizon. As it often is when commuting. It's not possible to tell when it's ready to be used again - so you find yourself habitually jabbing the button until it suddenly works.

It also doesn't cope with traffic lights or roundabout particularly well. Of course, one should concentrate on the road, but I found it common for the car to suddenly automatically accelerate towards a red light. As long as you don't use it for a substitute for paying attention, it's fine.

There are other software oddities. You need to turn on automatic windscreen wipers every time. Most cars have a physical switch, the i3 has a software toggle. Annoying.

The dashboard will tell you the speed limit for the road you're on. This seems to be controlled via a database in the car's GPS system - although it will pick up some temporary restrictions. It also "helpfully" makes a noise when you've accidentally gone over the limit.

There are three driving styles you can pick from - they control how quickly you can accelerate, the car's top speed, and whether the climate controls are on. Fiddling with them changes the range indicator on the dash - so you can see how many miles the air-conditioner costs you. On the most economical mode, acceleration is dampened, but you can override it by flooring the pedal.

But, at the end of the day, when all's said and done, what it comes down to, as a game of two halves - is that it's an exceptionally good car. Nippy, relaxed, and mostly easy to use. Whether it's zipping around town, cruising on a motorway, or sat in traffic, it's a pleasure to drive.


Broadly speaking, there are three ways to charge the i3. All systems will charge quickly to 80% and then slow down as they reach 100%.

  1. 3 pin domestic socket. 8 hours to charge to 80% from empty. Cable comes with the car.
  2. Type 2 Mennekes (Fast Charger). Will charge in 4 hours. There's a UK Government grant to install the chargers in your home. Requires a separate cable. Some chargers have a teathered cable.
  3. CCS - the Combined Charging System (Rapid Charger). Takes 30 minutes to charge. Cables are always teathered to the charging unit.

Really the only downside to charging is that the cables tend to drag along the ground - which means they can get a little dirty. Nothing worse than using a petrol pump though.

CCS cable on ground

I keep the cables in the boot of my car - as I'm reversing into a charging bay, it makes the most sense. There is a so-called "frunk", a front trunk which takes up the space where an internal-combustion engine would be. It's a little awkward to open (you have to find a hidden lever under the bonnet) and it isn't waterproof. Naturally, BMW will sell you a waterproof bag for £45... FFS!

At the moment I'm just using a domestic charger, but I've got a Fast Charger being installed in my garage by the fine folk at EV Charging Solutions.

I've got a big post in the works about the state of the UK's charging infrastructure. It's a bit of a mess at the moment - but seems to be getting better.

One nice thing about the i3 is the optional REX (Range EXtender) feature. When the battery gets down to 6% charge, the petrol engine kicks in. It doesn't power the wheels directly, rather it begins to recharge the batteries.


The petrol tank holds 9 litres (in the EU model). It can drive approximately 80 miles on a full tank.

80 miles / 9 litres = 8.9 MPL

1 mile per UK gallon = 0.22 miles per litre.

8.9 / .22 = 40MPG

That's a worse than my hybrid's 55MPG - but not massively. And, theoretically, it's only for short hops to get me to a charging station. So far I've not had cause to use the engine. Apparently it will switch on for a few minutes every so often just to ensure nothing gets clogged.

The cost of using the petrol will be roughly...

£1.26 / 8.9 = £0.14 per mile

A Word On Range Anxiety

Range Anxiety is a term coined by the petrol industry. It's supposed to convey how people worry when driving electric cars. It's nonsense.

Literally, every drive I do goes through a GPS first - so I know how many miles I'm going to travelling. Looking at my personal driving habits, it's extremely rare that I go outside an 80 mile radius. When I do, I'm travelling on motorways which have plenty of service stations - which all have charging ports. I don't know about you, but after 2 hours in a car, I'm ready to stretch my legs, have a sandwich, and take a piss - by the time I'm done the car is charged and ready to go.

If I visit a friend, I'll ask them to chuck an extension lead out of the window and trickle charge.

The excellent Zap Map shows a list of all public charging points in the UK.

Zap Map

Not yet quite as plentiful as petrol stations, but good enough for driving around the country. More are being installed, and more businesses are fitting power-points for their employees. For regular commuters who live within an hour's drive of work - electric cars are perfect.

Final Thoughts

This car is close to perfect for me. 90% of my car journeys are to work and back - which this can comfortably do in a single charge. As it happens, I can plug in at work - and the working day is enough to fully charge my battery. If I'm at home, I can charge overnight. If I'm working from home, I let the solar take the strain.

For those rare longer journeys, the UK has fast chargers dotted around the motorways - and the petrol engine will prevent me from being stranded by the side of the motorway.

I'm going to be saving around £1,000 per year in fuel costs. I'll admit, that does somewhat take the sting out of being gouged by BMW for their pricey extras.

It's a fun car to drive - and the smart features really do reduce the stress of commuting.

Yes, the software is naff - but you're hopefully not fiddling with it while driving. Perhaps BMW will spend some money improving it? Or opening it up for development?

Long story short? The i3 is a great half-way point between fully autonomous electric vehicles and regular petrol cars.

8 thoughts on “i3 Electric Car Review

  1. Martin says:

    "Miles per liter" is a perverse unit ;-). MPG is OK but mixing SI and non-SI hurts me. Please use "km per liter" instead...

  2. Paul says:

    Great article - however our UK gallons are bigger than US I thought?

    1. Terence Eden says:

      D'oh! Math(s) is hard 🙂

  3. maprrl says:

    Really enjoyed your article.

    Did you know that if you press and hold the unlock button on the fob, it'll wind down the windows? Press and hold the lock button (on the fob) it'll fold in the wing mirrors, hold it a bit longer and it'll wind the windows up? Give it a go. Works on my i3 😉

  4. You mentioned that your pin on your app is 1234 and that enough. Are you aware that you can unlock your car via this app? Maybe a better pin mine is 13 digits long. Have a look at G8YTZ on YouTube as he has a couple of interesting videos about the i3

    1. Terence Eden says:

      That's true - but my phone already has a complex password. I don't have yet another PIN on my email, or any other apps.

  5. Jorge says:

    Hi Terence, I own a 2015 BMW i3 REX and I was interested knowing you can plug an OBD dongle in to the OBD port and you mentioned that one can read the drive style stats. Can you please tell what hardware / software can be used with this car, and exactly what driving stats can you get - please enumerate. Thanks for this post!

    1. Terence Eden says:

      I don't have the i3 any more. I suggest that you buy any Bluetooth OBD dongle which is listed as compatible with the Torque app.

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