Punishment for my sins

[JohnOver]

When I drive to work 30 miles (11 of them down an 1800' hill and the rest at 65 on the freeway) and then I charge to 100% I have 102 to 104 miles of range. When I drive home from work (on the freeway and climbing that damn hill) and then I charge to 80% (83%) it shows a range of 60 miles.

It's just showing past miles/kWh and extrapolating. I don't remember how many miles back the system looks, I think it was 20 or 30 miles...

 

[planet4ever]

Well I hope I never actually see 0%. That would be cutting it a little too close for my blood.

I saw 0% last night after driving from Denver to Winter Park, CO.
<snip>
My question is... Does this mean that even though my last bar disappeared when I made one last Pizza run, did I still have 5 more kWh available in the pack or is that unusable reserve? Or ???

There's an interesting bit of history here. Spies wrote that first post in January. Back then you really didn't want to get down to zero bars, because if you did you were about to see the dreaded turtle. In March, Nissan made a firmware update to the car's computer which changed all that. I'm sure only they could tell you the whole reasoning behind it, and they aren't talking. But the net is that you can now drive quite a few miles after you lose the last bar. How many depends on where and how you are driving, of course, and there is some debate about kWh's available at that or any other time. My own theory, also not confirmed, is that each of the 12 bars now represents about 7.5% of the usable capacity, leaving 10% still available when the last bar disappears. At the bottom of that (purported) 10% is a tiny emergency reserve that should not be considered part of the usable capacity. That is turtle mode, and might take you half a mile with very little power. You don't want to go there.

But 5 more kWh after the last bar is gone? I don't think you will find many people who think it is anywhere close to that much. I'd say a bit more than 2 kWh, but if you drive at 35-40 mph with no more than two to three bubbles showing you can probably eke 15 miles or more out of it.

Ray

 

[aqn]

But 5 more kWh after the last bar is gone? I don't think you will find many people who think it is anywhere close to that much.

From my observation, each SOC bar represents 1.42 kWh. Twelve bars represent 17 kWh. The reserve, assuming the capacity is 24kWh, is 7 kWh.

Assuming that the miles-per-kWh displayed is accurate (a great big huge assumption), kWh-per-bar is then (tripmeter / miles-per-kWh) / (starting bars - ending bars). Over 49 charging events so far, the average I have is 1.42 kWh per bar.

Now, there are many factors that affect this number: temperature, whether driven in 'D' or 'ECO', trip routes, A/C usage, etc. However, a large number of datapoints will "smooth" out these variables. So far, it appears that it only took about 11 cycles or so to converge on a value. Back on Jun 28, after only 11 charging events, I got a kWh-per-bar figure of 1.44. Today, after another 38 charging events (19 charging cycles with driving done in 'D') and a summer of record high temperatures, the average is not much different: 1.42 kWh-per-bar.

So, given that real-world observed range-after-0-bars does not reflect a 7 kWh reserve (25.9 miles at 3.7 kWh), the only conclusion I can draw at this point is that either the battery's usable capacity is not 24 kWh, or the miles-per-kWh figure is quite bogus.

 

[planet4ever]

Assuming that the miles-per-kWh displayed is accurate (a great big huge assumption), kWh-per-bar is then (tripmeter / miles-per-kWh) / (starting bars - ending bars). Over 49 charging events so far, the average I have is 1.42 kWh per bar.

The real question I think you are ignoring is miles-per-what-kWh? The bars are presumably measuring how much electric capacity is remaining in the battery. But why would you expect miles-per-kWh to be based on all the capacity that is disappearing? Much more logical to me would be that m/kWh would be based on kWh that is appearing at the inverter. If so, it would exclude all energy used for the climate system, energy used by other systems in the car, including even energy used to cool the inverter, as well as heat lost in the battery and wiring.

Under my assumption, all you have shown is that each bar represents something more than 1.42 kWh. And yes, I did say, "there is some debate about kWh's available at that or any other time," so I don't consider 24 kWh available to be gospel.

Ray

 

[aqn]

But 5 more kWh after the last bar is gone? I don't think you will find many people who think it is anywhere close to that much.

Assuming that the miles-per-kWh displayed is accurate (a great big huge assumption), kWh-per-bar is then (tripmeter / miles-per-kWh) / (starting bars - ending bars). Over 49 charging events so far, the average I have is 1.42 kWh per bar.

The real question I think you are ignoring is miles-per-what-kWh? The bars are presumably measuring how much electric capacity is remaining in the battery. But why would you expect miles-per-kWh to be based on all the capacity that is disappearing? Much more logical to me would be that m/kWh would be based on kWh that is appearing at the inverter. If so, it would exclude all energy used for the climate system, energy used by other systems in the car, including even energy used to cool the inverter, as well as heat lost in the battery and wiring.

All that is true and you are correct that I am ignoring such information. Such information is interesting, but is not of practical importance to me. My observed numbers are pure real world, "bottom line" numbers that provide me with the most reliable and believable range information. My numbers may or may not apply to anybody else. Whether or not the numbers are accurate and precise, whether or not I know the kWh arriving at the inverter and consumed by the motor, is of secondary interest to me.

There are many variables: driven in 'D' or 'ECO', climate control, whether a SOC bar is at the beginning or at its end and is about to disappear, etc. Over many many iterations, those variables are smoothed out and values of interest to me (kWh per bar (1.42), miles per bar (5.41)) converge to a value that is valuable and meaningful to me . I did take pain to say "...the average I have...", "... I got a kWh-per-bar figure...", "...the only conclusion I can draw...", and not "...the average is...", "kWh-per-bar is...", etc. They are my observed information, which I believe more than anything I read here. They may or not match other observed data, and may or may not be of any use to anybody else, since nobody on this forum drives the same route in the same temperature in the same manner as I do. What they are, however, is a set of datapoints, which if significantly different from datapoints gathered via other methods, should be the basis for more head scratching, for me and everybody else. I am not dismissing anything.