I thought I'd expand a bit on how to determine range with a composite trip of city and highway driving.
It's relatively easy to get on the freeway, set the cruise control on 60 mph, and there's not much more to do. Assuming the conditions meet the parameters of the chart (level, etc), you'll knock out performance that matches the chart.
If conditions do NOT match the chart, you will have to use a bit of wisdom to determine how that might affect you. Going up hill, into a headwind, very hot or cold outside, and running the heater or a/c will reduce the chart data. Unfortunately, we do not yet have a chart formula to estimate how those parameters might specifically affect range.
Other issues extant to the above parameters are "cell balancing", which seems to affect how full the battery may charge (only affects 100% charge), and is easy to determine when the 12th fuel bar quickly disappears during your trip after a 100% charge.
The other end is more troublesome. If any one cell (of the 96) is not balanced, you may loose the last 5 to 10 miles of your range. I predict we'll have a way to measure the cells to determine whether those last miles are available. For now, however, it appears that the odds are overwhelmingly in your favor that you will make it, but
planning a trip to the last mile is bad form anyway. If you find yourself in a situation where you need those last miles, you'll have to roll the dice a bit.
Another issue is battery degradation, which there's not going to be a measurable amount yet, but that will be an issue a year or more down the road. I think we can expect 2%-3% reduction in range per 10,000 miles. The higher value if you work the battery hard (100% charges, numerous DC quick charges, running the battery to low energy levels regularly).
City driving can only be logically derived from average miles/kWh. My typical suburban southern California, non-freeway driving is about 4.5 m/kWh, so I'll use that for most of my planning. I'll adjust that for conditions that are not normal to me, and unfortunately, it will be tough for you to judge without a little seat time in your car to determine what's normal.
So, here's the composite part of using the chart. Let's say I'm planning a 90 mile trip. 10 miles will be suburban driving to the freeway, then 70 miles of freeway at 60 mph, and finally 10 miles of heavy city stop on go on a Friday evening before a national holiday.
For the first 10 miles, I'll use 4.5m/kWh.
For the next 70 miles, 3.9
For the last 10 miles, I'll use 3.0
So, here's the relatively simple [edited] math:
Code:
10 miles / 4.5 = 2.22 kWh
70 miles / 3.9 = 17.95 kWh
10 miles / 3.0 = 3.33 kWh
-----
90 miles total / 23.50 kWh = 3.829 kWh average
Can I make it? No, because a 3.8-ish m/kWh average will take me about 80 miles. Also, the total used of 23.50 kWh exceeds the 21-ish kWh usable battery capacity.
Could I make it?
Yes, if I slow down to 43 mph (not recommended, but instructive here) on the freeway.
Now I have:
Code:
10 miles / 4.5 = 2.22 kWh
70 miles / 5.2 = 13.46 kWh
10 miles / 3.0 = 3.33 kWh
-----
90 miles total / 19.01 kWh = 4.73 kWh average
90 miles total now equals a 4.73 m/kWh average, or almost a 100 mile range on level ground. Yes, we can make 90 miles, with almost a 10 mile reserve. Also, 19.01 is significantly below 21 usable.
Easy money, and easy math when done correctly [edit: my original "simple" math was done incorrectly, and has now been corrected here]
Yes, of course. We are all working off of the same model (1.5kWh per bar and 14 bars of available capacity). According to this model, 80% charge would correspond to 18kWh however. I don't know about you, but I am a bit concerned about mogur's numbers. One could argue that they are unusually high and won't apply to everyone, but still. They go against the model.
