EcoModder Forum Benchmarks EV and REx range

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 09-21-2023, 02:10 AM #1 (permalink) Engineering first     Join Date: Mar 2009 Location: Huntsville, AL Posts: 830 17 i3-REx - '14 BMW i3-REx Last 3: 45.67 mpg (US) Blue Bob's - '19 Tesla Std Rng Plus Thanks: 88 Thanked 236 Times in 149 Posts Benchmarks EV and REx range Hi, Benchmarks can be tricky so here are some pointers:Standard Day like:65-75 F little to no wind, best found after 11 PM to dawn Start = End for loop route, avoid tall hills Bi-directional runs over same route, average passes 10 miles (16 km) recommended distance one practice run to confirm no route issues like construction or accidents ~30 mph (48 kph) trip meter consumption kWh or MPG ~50 mph (80 kph) trip meter consumption kWh or MPG ~75 mph (120 kph) trip meter consumption kWh or MPG Use the three speed ranges to solve a quadratic equation:y = a*(v**2) + b*v + c :: v is velocity, y is consumption plot the consumption for ~30 mph to ~75 mph in 5 mph increments avoid going outside of the speed range in the curve Doing your own benchmarks, you can quantify the improvements (or loss) of tuning changes. This is completely independent of EPA metrics but specific to your vehicle. Bob Wilson __________________ 2019 Tesla Model 3 Std. Range Plus - 215 mi EV 2017 BMW i3-REx - 106 mi EV, 88 mi mid-grade Retired engineer, Huntsville, AL Last edited by bwilson4web; 09-21-2023 at 02:32 AM..
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 09-21-2023, 11:17 AM #2 (permalink) Somewhat crazed     Join Date: Sep 2013 Location: 1826 miles WSW of Normal Posts: 3,858 Thanks: 434 Thanked 1,065 Times in 941 Posts Note: standard day for aircraft has a much lower temperature iirc, 59f. Not sure what difference that makes in an electric vehicle with cooled batteries. Otherwise, cool concept __________________ casual notes from the underground:There are some "experts" out there that in reality don't have a clue as to what they are doing.
 The Following User Says Thank You to Piotrsko For This Useful Post: bwilson4web (09-21-2023)
 09-21-2023, 07:23 PM #3 (permalink) Engineering first     Join Date: Mar 2009 Location: Huntsville, AL Posts: 830 17 i3-REx - '14 BMW i3-REx Last 3: 45.67 mpg (US) Blue Bob's - '19 Tesla Std Rng Plus Thanks: 88 Thanked 236 Times in 149 Posts I agree about 59 F but I've shifted my temperature range up to avoid using the heater. My BMW i3-REx uses electric heaters and that eats into the range. I probably should mention turning off or minimizing all optional loads:A/C or heater OFF - heavy electrical load brights OFF - the LED low beams when testing at night IF safe I didn't mention calculating the 'density altitude' so you correct for temperature and altitude changes. But I don't look forward to explaining how it works. Bob Wilson __________________ 2019 Tesla Model 3 Std. Range Plus - 215 mi EV 2017 BMW i3-REx - 106 mi EV, 88 mi mid-grade Retired engineer, Huntsville, AL
 09-22-2023, 10:41 AM #4 (permalink) Somewhat crazed     Join Date: Sep 2013 Location: 1826 miles WSW of Normal Posts: 3,858 Thanks: 434 Thanked 1,065 Times in 941 Posts There's density altitude app computers for your phone, but they require an accurate base altitude. High air temperature tends to make the air less dense which is a minor drag improvement but can also make stuff draggy as boundary layer can go non laminar. Heaters in Huntsville? Until it gets to below 40f and I had to take the F250, I wore a coat. Didn't have the heat efficient so window defrost was the issue. __________________ casual notes from the underground:There are some "experts" out there that in reality don't have a clue as to what they are doing.