My Black Beauty, i3 94Ahr Rex

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Clanduncan

Active member
Joined
Nov 15, 2021
Messages
35
I've owned a '66 plate 2017, 94Ahr Rex for three years now. In this time I've seen the seasonal variance in range, from 100 to 135 miles electric, and 70 to 100miles on the Rex. My personal record for distance, without the Rex cutting in, is 132 miles with 9% battery still left. I drive evenly, and get an average 4.5miles / kwhr. In three years I've not seen any noticeable degradation in range, despite passing 88,000 miles, with the battery still reporting a kappa max of 27.6-28.2kwhr. I only charge to 100% when I need to, via Intelligent Octopus, usually setting a charge limit of 90%, which generally finishes at 85-95%. With the Rex option I have no range anxiety, but the option of travelling up to 220 miles without a recharge if I want to.

My improvement(s) have been;- (1) a larger 10.25" screen to replace the smaller 6.6" unit, sourced via AliExpress, fitted and coded myself for under £370, (2) all front lights (dip, high, side, indicator) are now LED as opposed to tungsten, with no additional electronics needed.
I considered (a) lowering springs, and wheel spacers to enhance handling, but it drives so well that I decided not to fit the springs, but kept the 15mm spacers, (b) sequential flasher lights for the wing mirrors, but was advised by an independent specialist that the electric mirrors can be fragile and break when changing bulbs, so haven't fitted those, (c) I looked at Havrla’s upgrades to a 120Ahr battery in the Czech Republic, which paired with a Rex should give a range of over 250 miles in summer. The guy is fantastic at what he does, but the costs are understandably so high, that if I ever had to replace my i3 battery it would probably be cheaper to get another 2nd hand i3 instead. What an adventure that would be though, upgrade and holiday all in one!

The wheels are original 'pizza' alloys, which I don't plan to change. I reckon the flatness of design is probably more aero efficient. Maybe I'll get them cleaned and refurbished at some future point, perhaps changing the colour to black, to match the rest of the car.

The only disappointment for me has been the poor radio reception on both FM and DAB. So, now I just use the usb socket for my own music, and rarely listen to the radio.

Three years after buying it, I'm still finding out features I didn't know about. Overall I wouldn't change this car for the world, and I certainly wouldn't go back to an ICE car.
 

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Upgraded 10.25" screen. Coded with my VeePeak ODB2 Bluetooth adapter, and a licensed copy of the Bimmercode app.
 

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Approaching 8 years old, and this is my HV battery health status after the most recent full charge. If you look at the figures, the SOC and SOH figures are very close to each other. Does that suggest that the battery is in near full health? Or does dividing battery capacity by rated capacity 87/94 seems to suggest over 92% available. Either seems like a very good figure to me at this point.
 

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Also have a 66 plate 2017 Rex and am very interested in learning what is involved in changing the lights from tungsten to LED.

I've owned a '66 plate 2017, 94Ahr Rex for three years now. In this time I've seen the seasonal variance in range, from 100 to 135 miles electric, and 70 to 100miles on the Rex. My personal record for distance, without the Rex cutting in, is 132 miles with 9% battery still left. I drive evenly, and get an average 4.5miles / kwhr. In three years I've not seen any noticeable degradation in range, despite passing 88,000 miles, with the battery still reporting a kappa max of 27.6-28.2kwhr. I only charge to 100% when I need to, via Intelligent Octopus, usually setting a charge limit of 90%, which generally finishes at 85-95%. With the Rex option I have no range anxiety, but the option of travelling up to 220 miles without a recharge if I want to.

My improvement(s) have been;- (1) a larger 10.25" screen to replace the smaller 6.6" unit, sourced via AliExpress, fitted and coded myself for under £370, (2) all front lights (dip, high, side, indicator) are now LED as opposed to tungsten, with no additional electronics needed.
I considered (a) lowering springs, and wheel spacers to enhance handling, but it drives so well that I decided not to fit the springs, but kept the 15mm spacers, (b) sequential flasher lights for the wing mirrors, but was advised by an independent specialist that the electric mirrors can be fragile and break when changing bulbs, so haven't fitted those, (c) I looked at Havrla’s upgrades to a 120Ahr battery in the Czech Republic, which paired with a Rex should give a range of over 250 miles in summer. The guy is fantastic at what he does, but the costs are understandably so high, that if I ever had to replace my i3 battery it would probably be cheaper to get another 2nd hand i3 instead. What an adventure that would be though, upgrade and holiday all in one!

The wheels are original 'pizza' alloys, which I don't plan to change. I reckon the flatness of design is probably more aero efficient. Maybe I'll get them cleaned and refurbished at some future point, perhaps changing the colour to black, to match the rest of the car.

The only disappointment for me has been the poor radio reception on both FM and DAB. So, now I just use the usb socket for my own music, and rarely listen to the radio.

Three years after buying it, I'm still finding out features I didn't know about. Overall I wouldn't change this car for the world, and I certainly wouldn't go back to an ICE car.
 
If your rear lights are LED already, then you should be able to swap front lamps over without any problems whatsoever. It was a straight swap for me, without any flasher problems. Headlamps too, and two out of three front lamps accessed behind a cover in the front wheel wells.
 
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If you look at the figures, the SOC and SOH figures are very close to each other. Does that suggest that the battery is in near full health? Or does dividing battery capacity by rated capacity 87/94 seems to suggest over 92% available.
It seems pretty straightforward that 87.3% SOH indicates that your battery pack has lost 12.7% of its new nominal usable capacity. However, I don't understand the reported maximum actual SOC, 85.3% in your case, because your cell voltage at a full charge, 4.13 V, is what it would have been when your battery cells were new. The actual SOC is likely the same as it would have been when your battery pack was new with the BMS assuming that the energy corresponding to 1% SOC has remained constant over time which isn't true. Adding the 12.7% capacity loss to the reported current actual SOC, 85.2%, would approximate the current actual SOC, 97.9%. That seems a bit high, but all of these values except for voltage are calculated estimates, so there is almost certainly some error in these values.
 
Alohart;- I had been assuming the BMS buffers which lock away 15% of the battery (assumed 7.5% at top and bottom) was a factor. The figures seemed too coincidental otherwise. The battery was at 100% as reported by the car.
I'm more than happy with the battery health, and not particularly worried about the future capacity. If I was, I'd take it to Havlra in the Czech Republic to have an upgrade!
Thanks for your input, it's been informative to have this discussion, as it's increased my knowledge on the car. 👍
 
An up to date look at how effective (efficient?) such a unique car can be. This is mine after the last three months of usage. The trip computer is reset every 3 months or so, with these figures being the spring ones. Mostly urban driving, with a handful of longer trips, and/or motorway (60mph) journeys included.
 

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