So what ranges are you getting?

[Gonville]

As long as you know how to get split screen all is well.....



That's with some Eco-pro but quite a bit of rapid acceleration too

 

[fdl1409]

Hi Surge,

yes, I always drive in EcoPro+ - for the 5 days I have had the car. However, I do quite a few full throttle accelerations for the fun of it.
It takes some time to develop the right feeling for efficent driving of an electric car. As I previously had an i-MiEV, the learning process with a new car doesn`t take quite as long. I am confident more is possible.

My result of today isn´t even near a record. In the German i3 forum, somebody reported 212km ( 132 miles ) with one charge with 6km ( 4 miles ) remaining 3 days ago:
http://www.goingelectric.de/forum/bmw-i3-batterie-reichweite/reichweite-212-km-t5089.html
That was with a BEV, and with low speed. He felt like an obstacle and won´t do that again.
Somebody else did 192km with 12km remaining.

Frank
Germany

 

[Bunter]

85 mile trip at between 6 and 10 C with 4 miles remaining at the end. Eco pro mode with occasional climate control to demist. 55 mph limit in Eco Pro only occasionally exceeded (5 miles at >55 <70). BEV.

But I have had more reported by the car, see below a recent high, 111 miles of range - obviously an artefact.

Bill

 

[fdl1409]

Yesterday and today total of 160.1km ( exactly 100 miles ) with 16% SOC remaining. Urban and country roads, according to computer 10.0 kWh/100km = average of 6.25 miles per kWh. i3 REx.

Frank
Germany

 

[Lecram]

Today I achieved 186 kms (116 mls). I had 7 kms (7%) left on the display (10-12 km in real). After 186, the Rex switched on. Since the Rex is on, you cannot turn it off at low battery level.

 

[Surge]

Anyone have actual experience with winter range? Specifically -10 C (14F) without preheating the battery first?
Trying to see what the real world range reduction would be.
Some say 60% reduction(!) others say 20%.

 

[woof]

Anyone have actual experience with winter range? Specifically -10 C (14F) without preheating the battery first?

Sorry, not yet!

Some say 60% reduction(!) others say 20%.

ActiveE had 30% reduction (70 miles winter vs 100 miles summer) here in Mass., which includes -10C for some of it. I could easily get 90 miles on very cold clear winter days if I ran sans heat, so 20% loss due to heating and 10% due to other. Snow days I stayed home.

No way the BEV with heat pump will be worse than 20%. And the i3 will let the heated seats work in eco-pro mode while the ActiveE did not. It's much easier to run without cabin heat when your butt's warm!

 

[Surge]

Thanks, this is very useful and helpful!!

 

[amateurish]

Today I achieved 186 kms (116 mls). I had 7 kms (7%) left on the display (10-12 km in real). After 186, the Rex switched on. Since the Rex is on, you cannot turn it off at low battery level.

That is very impressive. How did you manage it?

 

[Surge]

I put together a simple spreadsheet that gathers the main factors affecting range for both models:
- extra weight for REx (approx. 5-10% loss of range, depending on speed)
- winter range reduction (<32F) (20% for BEV and 27.5% for REx due to loss of heat pump)
- normal range estimates come from Tom's blog post and comments
- battery life reduction of 30% is an estimate for age; we know the BMW warranty applies to a reduction below 30%, so 30% is the key target. A 29% reduction will not be covered by BMW.
- safety buffer - this is personal, but it would be higher for me in the BEV

When you add it up, in the worst case (cold weather, highway, battery age), the REx should do between 59 and 106 miles (both battery and gas engines), whereas the BEV should do 22.5-47.5 miles.

I need to be able to rely on at least 60 miles per day, so this decides it for me. As much as I wanted to go with the BEV, I will go with the REx… :shock: :shock: :?

Let me know your comments on the spreadsheet:
https://drive.google.com/file/d/0B57oGhsDUwHsclI3T05jUXo1Qmc/edit?usp=sharing

 

[fdl1409]

You really are persistent...

Once more you write that extra weight will cost 5-10% range. This is definitely exaggerated. Make it 2% for the weight and you will be much closer.
Same about the rest. I really want to see you drain a battery in 22.5 miles. Nearly impossible.
I agree you can`t rely on 60 miles with a BEV, so the REx is a logical decision.

Report to us next winter.

Frank
Germany
i3 REx

 

[Surge]

Frank, help me understand why the range is only 3% affected due to weight? At low speeds, if you are pushing 10% more weight, wouldn't you expect to consume 10% more energy?
I understand that at higher speeds drag and aerodynamic resistance forces have an increasing impact, but what about a low city speeds?

https://drive.google.com/file/d/0B57oGhsDUwHsYjdITHBCaXk4ekU/edit?usp=sharing

 

[Surge]

Same about the rest. I really want to see you drain a battery in 22.5 miles. Nearly impossible.

Seems quite possible - this is using data from various owners, just combined to account for high speed (120 kph), low temperature, and an older battery.

22.5 miles is certainly very low for the BEV! I wonder if most people actually realize this?!

 

[amateurish]

Frank, help me understand why the range is only 3% affected due to weight? At low speeds, if you are pushing 10% more weight, wouldn't you expect to consume 10% more energy?

No, you wouldn't. At a constant speed most of the energy consumed relates to air resistance, and weight is irrelevant to that. Even at low speeds, weight is only relevant to rolling resistance.

 

[fdl1409]

Even the Tesla, which has >50% higher weight, only uses something like 6 kWh/100 miles to overcome rolling resistance. For an i3, that translates to less than 4 kWh/100 miles.
The difference between BEV and REx is 120kg in the summer with wider rear tires for the REx. In the winter they have the same tires, several kg less difference. Also, you are calculating with a heat pump in the BEV, which has some extra weight. The total difference then ought to be below 100kg, something like 8%. 8% of 4 kWh/100miles is very little indeed considering that you believe that a battery will be emptied in 50 miles or less, which means that you would need 35 kWh or more for 100 miles. Weight really adds very little difference to that.
Weight not only increases rolling resistance, you also need more energy to accelerate the car. Most of that you win back when you decelerate and with regenerative braking. Kinetic energy goes with the square of speed, so this is rather low in slow urban traffic.

Why don´t you make some tests. Make a trip with 3 extra persons of 100 kg each. Will power consumption go up by 30%? Certainly not. I predict less than 10%.

Frank

 

[ultraturtle]

...you write that extra weight will cost 5-10% range. This is definitely exaggerated.

The jury has been in on this for some time. BMW has measured the difference to be less than 5%, and the EPA has measured it at 6%, to include the tiny aerodynamic drag penalty of the wider rear wheels. The answer is 4.65% to 6.0%. Case closed.

 

[WaffleHouse]

I finally got my i3 BEV this week... very excited! I was very curious to see whether the battery would manage a roundtrip I make to a nearby city every once in a while (btw, I'm in Spain). My destination in that city is exactly 50 km away (31miles) from home, and most of the drive there is on a highway.
So I turned on EcoPlus, and with average highway driving speeds of around 115km/h (71 m/h), and no aggressive maneuvers, I managed to complete the round trip with about 12 km (7 miles) remaining. So in other words, for the roundtrip, I got 100 km range + 12 km remaining = 112 KM (69 miles). BTW, the range estimate for the trip given by my navigation system before my departure was pretty close. My dealer told me I will see an improvement in the next few weeks and months as the i3 learns my driving habits. I don't know how accurate that is.
All in all, I'm a happy customer.

 

[I33t]

Frank, help me understand why the range is only 3% affected due to weight? At low speeds, if you are pushing 10% more weight, wouldn't you expect to consume 10% more energy?
I understand that at higher speeds drag and aerodynamic resistance forces have an increasing impact, but what about a low city speeds?

https://drive.google.com/file/d/0B57oGhsDUwHsYjdITHBCaXk4ekU/edit?usp=sharing

There are more factors than weight involved, and once up to speed weight has little impact. Changes in speed is what consumes the most energy at low speeds, so cruising along at 50kph won't be much different between BEV and REX but accelerating from the lights to 50kph and bringing that extra 120kg up to speed will consume more energy.

I'm guessing that the biggest margin between BEV and REX consumption will be seen in low speed stop/start driving.

 

[fdl1409]

Yes, you need more energy to accelerate the extra mass. But, not all of that is lost. If you reduce speed, the kinetic energy of the moving mass will be recovered, in neutral mode the heavier car would roll a longer distance. Only that part which is consumed by higher rolling resistance is lost. If you decelerate with regenerative braking, some extra power will be restored to the battery.

Frank

 

[I33t]

Or if you use the brakes...