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Discussion Starter · #1 ·
Last night I was on a long trip back and had to use the REx for a while and rather than use it with battery remaining i decided to run the battery down until it was zero and see what performance the REx on its own gave and what speed it could sustain.

I remember hearing before I got my i3 that some people were concerned about the small engine size if you found yourself with an empty battery, so I did my own experiment.

The REx kicks in with what seems about 5% battery left, normally around 3 miles of range, so as it was late I drove quite hard to deplete the battery more than the REx could sustain. I had to really drive hard...

Anyway, I got it down so the power available reduced significantly and then set the cruise control to 80mph which seemed out of reach, thus making it work as hard as possible to speed up and not have spare power to put extra charge into the battery.

After half a mile of the car effectively going flat out in the reduced power state the speed held steady around 73 - 74mph. I was on a pretty flat dual carriageway, going north on the A11 past Cambridge if anyone knows...

My helpful girlfriend took some pics of the dash to prove the situation. The first two photos are half a mile apart and show the max power as around 2 of the normal 11 or 12 bars. For those who don't know the dash layout, normally the 'ePower' is the same colours as the 'Charge' when the battery has enough charge for full power to be used.

After a few miles I decided to back the speed off to 70 mph and see how quickly the car returned to 'normal' power and it was surprising. I would say that within a mile or two of constant 70mph I was getting the power level back to normal.

The last picture shows this when it had recovered enough charge for around 2/3rds max power to be available.

So all in all, if you have the REx, even if you drive it hard when the battery is close to empty, if you then cruise on a flatfish road at below 70 mph then the battery should recover enough charge for normal functionality within a few miles.

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Discussion Starter · #3 ·
Flatfish road hey? Don't you love autocorrect?

Very interesting results, less fuss than we may have been lead to believe in the past.
]
Autocorrect? I meant flatfish... Haven't you tried those types of roads? They are squidgy but give poor efficiency...

Potentially yes... I would expect if the battery was absolutely empty and then you went uphill then it could pose a problem to top speed. In what I would class as typical situations though, with a completely flat battery, I cannot see you dropping much below 60/65mph on hills
 
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Just out of interest, what do you think would happen if you ran out of charge at 70, had to slow for an exit and then wanted to get back up to 70. Do you think the regen from slowing would put enough back in the battery to accelerate up?

Extreme I know ...
 

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Discussion Starter · #7 ·
Just out of interest, what do you think would happen if you ran out of charge at 70, had to slow for an exit and then wanted to get back up to 70. Do you think the regen from slowing would put enough back in the battery to accelerate up?

Extreme I know ...
Yes, the car will surely accelerate back up, but just slowly after the charge from the regen has been used.
I will try this another time and report back!
 

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I think a lot of the concern originated in the states, where climbs of over 5000 feet are not uncommon - done some amazing motoring in the Rockies, myself (the Rockies were amazing, my motoring was boggo) - we just don't have the same type of terrain over here.
 

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Discussion Starter · #9 ·
I think a lot of the concern originated in the states, where climbs of over 5000 feet are not uncommon - done some amazing motoring in the Rockies, myself (the Rockies were amazing, my motoring was boggo) - we just don't have the same type of terrain over here.
Very good point Mark.
For the UK it's not an issue really but can understand in mountain ranges it could be an issue. The REx seems a good compromise to me though.
 
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I think a lot of the concern originated in the states, where climbs of over 5000 feet are not uncommon - done some amazing motoring in the Rockies, myself (the Rockies were amazing, my motoring was boggo) - we just don't have the same type of terrain over here.
At least one of the UK media outlets carried out an early test and seemed to have great difficulty, I think this is where a lot of it stemmed from.
 

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I think a lot of the concern originated in the states, where climbs of over 5000 feet are not uncommon - done some amazing motoring in the Rockies, myself (the Rockies were amazing, my motoring was boggo) - we just don't have the same type of terrain over here.

Also in the US the rex is not allowed to come on untill the battery is at its min. I think its all a bit of a side issue any way, if I had a i3 I would use it like a LEAF with stabilisers and only rarely use the rex.
 

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Very good point Mark.
For the UK it's not an issue really but can understand in mountain ranges it could be an issue. The REx seems a good compromise to me though.
Which is why I can't wait for mine to be delivered. So as a proper pedaller, unlike us uncoordinated schlubs, how do you rate the dynamics of the i3?
 

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At least one of the UK media outlets carried out an early test and seemed to have great difficulty, I think this is where a lot of it stemmed from.
But it seems the only way to get into that difficulty is driving at Racing Driver pace ;)
 
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Discussion Starter · #15 ·
But it seems the only way to get into that difficulty is driving at Racing Driver pace ;)
I 'might' have sat at 90+ for a couple of miles to actually get the battery to drop sufficiently for it to reduce power. Or a series of max accelerations...
The REx is absolutely sufficient for UK motoring in my opinion.
 

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@Paul can we start asking for id's for new members and visitors to insure the Police are not monitoring everyones admissions of lawless behaviour:)
 

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A bunch of Ampera drivers will be along soon to tell you that your experiences are delusional and are only your personal facts :)
 

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Discussion Starter · #19 · (Edited)
Which is why I can't wait for mine to be delivered. So as a proper pedaller, unlike us uncoordinated schlubs, how do you rate the dynamics of the i3?
All things considered, I think the car handles pretty well.
I had a 420d Sport before which had top notch tyres on, that was stunningly well balanced and had oodles of grip for a road car so the standard is high to compare against...

The i3, like any EV, is very responsive to throttle inputs. I think the car 'squats' nicely when you floor it and rarely breaks traction, even when cornering hard. I would say that grip in the middle of corners is where its weaker and this is simply due to the width of the tyres... It has a smaller contact patch and you cannot get over that.
The balance is very nice and sensible though. I would probably say there is a sniff of understeer, this is always the best for road cars as the average driver would struggle to sensibly control a car oversteering.
The brake pedal seems to be very firm and when you need to really use the brakes, they stop the car surprisingly well considering the size of the discs.

Overall its a great little car and sooo much fun :)
I am privileged enough to have a Roadster as well and yet the i3 is still the car of choice for any trip under 100 or so miles!
 

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Discussion Starter · #20 ·
A bunch of Ampera drivers will be along soon to tell you that your experiences are delusional and are only your personal facts :)
Really?! Well I don't think I was in a delusional state when driving last night.

Let me just check

........................

Yup, just asked my girlfriend who was sat in the passenger seat and she said I was conscious and she seemed to take the same conclusion from our experiment on the A11.

I am absolutely open to others having different experiences and having different opinions but what I did in those conditions was fairly clear to me.
 
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