PiroRex
Posts: 2
Joined: Sat May 23, 2020 2:04 pm

Range Extender for i3

Sat May 23, 2020 2:11 pm

As I own (or better to say - my WIFE_QUEEN_OF_LIFE owns) a BMW i3 2018 94Ah REX, I just drive with an additional electronic, called "range extender".
Found on the Internet.
Please let me know, if my results are typical, or better than average.
Our results seem to have improved by about 10%, but I'm not sure about it.
What's your average?

Image
BMW i3 REX 2018 (Wifey Flagship) + Tesla Model X P100D. evtun.com EVSE + Grid Monitoring

alohart
Posts: 2023
Joined: Sat Nov 01, 2014 7:36 pm
Location: Honolulu, HI

Re: Range Extender for i3

Sat May 23, 2020 7:02 pm

Recuperation values are difficult to assess.

The most efficient driving is a recuperation value of 0 kWh/100 km which means that all decelerations are accomplished by coasting only (i.e., no regenerative or friction braking). This is impossible to accomplish in real-world driving.

If one decelerated only by pressing the friction brake pedal very aggressively, regenerative braking would occur over a short period of time resulting in a low but greater than 0 kWh/100 km recuperation value which is the least efficient way to drive (much of the vehicle's momentum would be converted to waste heat by the friction brakes).

If one decelerated using only regenerative braking, a higher recuperation value would result. Stop-and-go traffic should result in a higher kWh/100 km value due to an increased frequency of regenerative braking. Driving efficiency would be worse than coasting but better than aggressively friction braking. This describes how I drive most of the time in our suburban/urban setting with frequent traffic lights and generally moderate traffic. The BMW Connected app claims that 21 mi/kWh (3.0 kWh/100 km) is my lifetime recuperation value over 5.5 years of driving our 2014 BEV.
Aloha,
Art

2014 BMW i3 Arravani Grey, Giga World, Tech + Driving Assist, Parking Assist, DC Fast Charging, JuiceBox EVSE

PiroRex
Posts: 2
Joined: Sat May 23, 2020 2:04 pm

Re: Range Extender for i3

Sat May 23, 2020 11:31 pm

To be honest, I see that now regeneration values started to be much higher.
Theoretically I coast now much more, as with that electronic add-on Wifey's BMW coasts more. But regen power is increased now, maybe this is the cause, why total regen increased rapidly.
It is easier now to keep it exactly at the "zero power" point, it is enough to touch accelerator pedal.
The range seems better, but I must do a "synthetic" test with box on and off.
I also think, that there will be no range gain at highway speeds - no way to beat physics.

I will report more after test, not only my guessing.
BMW i3 REX 2018 (Wifey Flagship) + Tesla Model X P100D. evtun.com EVSE + Grid Monitoring

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