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      08-11-2020, 04:49 PM   #7
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Drives: BMW i8
Join Date: Nov 2019
Location: Germany

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Originally Posted by MolarBear View Post
So I've been doing a lot of watching of the energy distribution screen during motorway journeys and have come to the following conclusions:
1. That at a constant speed of 70mph (British motorway speed) only the ICE will work and gives about 40mpg.
2. If you pop it into sport, charging at the same time gives about 22mph so roughly half.
3. Electric operates until 55mph when the ICE kicks in, then after this a lot of the time accelerating will have an electrical assist even if just accelerating slowly - it doesn't need to be in kickdown to get e-boost. I suspect that the electric motor just helps keep the ICE at a constant RPM and it just helps the economy that way but doing a lot of the acceleration - this is shown in the energy transfer screen as electric assist or something to that effect. However once it is cruising it appears to be strictly ICE. The battery does not get used.
4. The electrical range seems to only indicate range until 10% charge - perhaps it keeps this for e-boost performance as a minimum? If you're near home then you can add about 3 miles to the range remaining (for LCI at least) if you're going to charge it when you get back and don't need the boost for a later drive.
5. Just a quick guess here, and I need to monitor more extensively but:
At 30 mph it takes about 2-3% per mile on the power.
50 mph its about 3-4% a mile
70mph it will chew through at 5-6% per mile.
You should add that's the old, small battery i8, correct?