Absolute maximum range? (sacrificing travel speed, heat, etc

I bought my BEV earlier this week and been driving it for two days. So far so good. It is a mid-2015 model with 4000 km on the clock. The main use for the car is to commute 100km round trips, which it should do fine.

My question is, as per title, how far it is possible to drive with a full battery if you shut down everything unnecessary and are willing to reduce your travelling speed to, say 60 km/h (or even less, what is the optimum speed for range?) You may presume an open road with no traffic.

I'm mostly interested in non-range-plus figures. Range plus should be then only a simple multiplication.

In optimum conditions you should be able to drive more than 160 km on a normal charge. The major factor here is outside temperature - whether you heat the cabin or not, the range will drop dramatically once it gets colder outside.

Off the top of my head (beware), here is what I think in terms of eating kWh.

1. Outside temperature, i.e. cold battery.
2. Running heater.
3. Rabbit starts.
4. Not keeping it below the first green bar.
5. Using the brake vs. regen via D- to recover max energy.
6. Letting anyone else in the car or horrors letting them drive it.

KLuuppo said:

My question is, as per title, how far it is possible to drive with a full battery if you shut down everything unnecessary and are willing to reduce your travelling speed to, say 60 km/h (or even less, what is the optimum speed for range?) You may presume an open road with no traffic.

Click to expand...

Interesting question.

I've managed a little over 180 km, at 20C, with a mix of city / highway driving (but not exceeding 80 km/h). Basically, pretty strict hypermiling. That's efficiency of approximately 4 miles / 6.42 km per kWh.

Theoretical scenario:

Temperature = 20C
Wind = calm
Road = closed test loop, paved & flat
Tires = 50 PSI
Full charge = 28 kWh
Constant speed = 60 km/h
Cruise control = On
All interior electronics / lights / temperature controls = Off

I'd assume you would achieve efficiency of at least 5 miles (8 km) per kWh if not better. At a minimum, 28 x 8 = 224 km but I wouldn't be surprised if 240-250 km was possible given those ideal test conditions. There are a number of extreme range tests that have been done with the Nissan Leaf that you can google. Even though our cars are heavier, the result shouldn't be all that different (other than the difference in battery capacity) given the above test conditions.

I can think of better things to do than driving 60 km/h for up to 4 hours - but if it is an absolute answer you seek, fill your boots.

*EDIT*

Found this:

https://www.youtube.com/watch?v=HePkEx06-F8

A couple of guys that took a Tesla P85D and hypermiled it at 40 km/hr for 729km using 77.5 kWh. That's an amazing 9.4 km per kWh efficiency. Since our motor is essentially the same (but detuned) unit that goes into a Model S, and taking the coefficient of drag out of the equation (again, driving 40 km/h) - it's reasonable to assume that it's possible that a B250e could also achieve 9+ km/kWh efficiency. So yes, 250 km of range should be possible with our cars.

Thank you for the informative replies! I'm looking forward to get my 11kW wallbox here and installed, so I could do some test runs with different speeds.

I know that energy consumption per unit distance goes up with the square of velocity. However, I do not have a gut feeling for the actual consumption at different speeds. If one can achieve 250 km range going 40km/h, could you go 1000km if you drove 20 km/h? Most likely not, as constant consumers like lights and heating will eat your capacity. On the other hand, going 160 km/h would give you an expected range of 20 km.

Especially with the weather here (-19°C today, -25 tomorrow) the heating will push the optimum speed upwards. But how much, I can't say.