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Old 01-05-2016, 08:25 PM   #12
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It is now January 2016 and my i3 REX is not doing so well on battery power. It seems to be influenced by:
lower temperatures - around 6C
the need to heat the cabin
the need to demist the front windscreen

I now know why the Mode is called "Comfort" as it is the only one the warms up the car quickly enough. I start a journey in "Comfort" mode and switch to "Eco Pro" as soon as the car is warm enough and I am now getting about 62-67 miles on battery running round Milton Keynes. I also find the car mists up the front windscreen quickly compared to other cars I have owned when in Eco Pro mode. I try to reduce the need to use the air-conditioning for demisting by setting the air flow to the screen only and that does help.

I wonder how far it will go on battery with heating on full and temperatures below freezing? This reduced range in winter makes me even more glad that I got the REX version. I also wonder whether the petrol engine will be able to hold the charge on a long winter journey in very low temperatures without having to drive at stupidly slow speeds. You can't do a lot with about 34 bhp.

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Old 03-03-2016, 04:56 PM   #13
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My i3 REX is down to about 55-60 miles range when the temperature is below about 5C and down to about 0 degrees C. This is when driven carefully and switching between Eco Pro for heating and Eco Pro+ [with fan off] for as long as possible.

I have achieved 100% efficiency on some short trips with the temperature at 0-7C and so I can achieve good battery use BUT the problem is that heating uses much battery power. What is doubly annoying is that in Eco Pro mode, when the car reaches the set temperature [20C], it stops heating and the fan stays running thus blowing cold air at me - not what I want. I therefore have to switch the fan off. I am not impressed by this. I have to say that "Comfort Mode" really is a good name as it is the only mode where you are really comfortable in winter.

I agree that pre-heating the car helps, but I am not so sure I would set off on a long journey with the threat of freezing weather. In fact, I have decided against doing so and will use one of my old Citroens instead. As far as I know, if I am stuck in a traffic jam at 2C, the REX will not run unless the battery is down to the last 6 miles or so [the auto switch-on point]. Therefore being stuck in a traffic jam uses up battery and one hopes the jam does not last too long!
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Last edited by citnuti3; 03-03-2016 at 09:38 PM.
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Old 05-31-2016, 07:49 PM   #14
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During my first winter with the i3REX [in England], the heater was needed and that reduced the range considerably. In "Comfort" mode I was down to 55-60 miles when adding together the distance driven and the battery distance still available. If using "EcoPro", it improved somewhat BUT I was not happy with the car blowing cold air in when it go up to temperature. I had to switch the fan off to stop the cold air flow. The last car I remember this happening with was on my 1995 VW Vento VR6 that did not have aircon.

We did a trip from home in Buckinghamshire to north London on a cold winter's day with the temperature just above freezing point. The car was pre-heated and thus warm when we set off and I used "EcoPro+" mode. The heating and aircon was "off". Much to my surprise, the car stayed warm for the 52 mile trip and I used the fan to clear the windscreen twice. This was a better performance on heat retention than I was expecting.

It is now the end of May and in "EcoPro" mode and driving gently I am back to 75 miles on battery.

What is clear to me is that driving an electric car involves a lot of compromises in winter and, I assume, in very hot weather with the aircon in use. An i3 REX is not a replacement for a "regular" petrol/diesel car in my opinion. To put it starkly: one of the old cars I own is a Citroen Visa Special with a 35bhp twin-cylinder engine. It has a top speed of 78 mph, a 0-60 mph time of between 26 and 30 seconds and it hates hills and or heavy loads. Its twin pot engine is the same size and power as the one in the REX i3 and to maintain charge in the i3 REX, you need to be using less than 35 bhp on average and effectively be driving it like the Visa 652cc: slow on acceleration and cruising at 56- 64 mph. If you are driving on battery, I think that the good mileage range comes when driving as if the car still only had 35 bhp. That is the compromise. Fortunately, the i3 can accelerate [using more than 35 approx bhp ] when needed but that will use up more battery each time you do it than the REX can replace in the short run.

The i3 REX is good but a long way from perfect!
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Old 08-18-2016, 11:05 AM   #15
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With 6,400 miles now driven, I recently achieved 92 miles on one charge and 8 miles "in reserve" when we got home - this is with an i3REx. The route was mainly motorway and I cruised at 56 mph approx. in EcoPro+ Mode. The return journey had a few minutes of aircon use at the start to cool down the car after it had been stood in the sun for several hours.
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Old 05-03-2017, 06:39 PM   #16
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In April 2017, my i3 REx went in for its first service at nearly 9,000 miles [and first time back to a BMW dealer in nearly 2 years] and had the bolts replaced on the engine mounts and a replacement charge control unit. The car required a software update to - as I understand - moderate the initial torque when setting off to stop any twisting of the petrol engine mounting frame.

As a result of the software update, the indicated range has improved and running around Milton Keynes in EcoPro+ and runs of 40 miles, it is now showing over 80+ miles based on miles driven and claimed miles left in the battery. What I have not yet discovered is whether this is a real increase in range or whether the battery charge indicator is more optimistic at the full end of the battery than it was and will lose miles more quickly as it drops to low a percentage charge.

I also wonder if BMW is now more confident with the battery and is allowing more of the total capacity to be used when driving.

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