Range Chart

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davewill said:
Everyone is simply guessing about charger efficiency. At least the 21 kWh number is useful when combined with the dash mpk.


Yes, we are guessing. But, if we're going to use the energy consumption numbers that match the speed, then that number comes up to 21kWh.

What it really is.... seriously, it's not important except as a number to divide/multiply by.

3.9kWh will roughly correspond to 60 mph and a range of 81.9 miles.... those numbers work close enough for most people's use. And to get there, we had to use 21kWh.

Tony
 
mogur said:
I believe the total KwH of power put in to the battery when charging to be a more reliable indicator of capacity since it leaves little room for error or interpretation... Basically, the only variable is the actual charger efficiency, but that is pretty well known at this point.


Apparently, something doesn't add up. If the charger efficiency is "known" (but, admittedly not measured), then the "miles/kWh" that's on the dash doesn't add up.

So, which is wrong, the dash consumption number or the usable battery amount?
 
evnow said:
Some things to be corrected, though :
- The top says 24kw/h battery. Should be changed to 21 and kWh (not kw/h).
- 6.4kwh, 5.2kwh etc should change to 6.4 m/kWh

Also, only a constant 38mph run might give 138 mile range. I think that 38mph mentioned along with other range by mph figures, confuses people (eg. why does 25 to 45 mph give only 108 miles if 38 gives 238 ?).


Well, the advertised size is 24kWh. No where does it say otherwise, but only through our collective efforts do we think that 21kWh is a more logical choice. That's why it's a note at the bottom. If it were renamed, that would be the first thing they would read.... hey, that's not for my car, I have the "big" 24kWh" batteries.

We do the same in fuel tanks on airplanes. It may hold 100,000 pounds of fuel, but only 99,823 are usable. We don't then call it a 99,823 tank.

Yes, I've already seen that confusion. Maybe rename that 40-45mph?

Thanks for the critiques.

Tony
 
TonyWilliams said:
We do the same is fuel tanks on airplanes. It may hold 100,000 pounds of fuel, but only 99,823 are usable. We don't then call it a 99,823 tank.
I see what you are saying - I thought you had just forgotten to update.
 
mogur said:
I believe the total KwH of power put in to the battery when charging to be a more reliable indicator of capacity since it leaves little room for error or interpretation... Basically, the only variable is the actual charger efficiency, but that is pretty well known at this point. My numbers from TED have been very consistent in this regard and show close to 24KwH usable when I run it down to dead or turtle...
Well, we can call it "usable" if you want. But the figure 21 kWh is way more useful than other figures.

Anyway, what do you think is the charging "efficiency" ? Using the at wall m/kWh and dash shown m/Kwh, I get the efficiency as about 82%.

totalkwh.png
 
The most recent time I ran it down dead, I put in 26.67 KwH from the wall to 100 percent...

evnow said:
Anyway, what do you think is the charging "efficiency" ? Using the at wall m/kWh and dash shown m/Kwh, I get the efficiency as about 82%.
 
mogur said:
The most recent time I ran it down dead, I put in 26.67 KwH from the wall to 100 percent...

evnow said:
Anyway, what do you think is the charging "efficiency" ? Using the at wall m/kWh and dash shown m/Kwh, I get the efficiency as about 82%.
Which proves? My calculator says 0.82 * 12.67 = 21.87. That's a lot closer to 21 than to the 24 you seem to be insisting on, mogur. A 24 kWh total battery capacity with 10% reserved (unusable) makes sense to me, and leaves us with 21.6 kWh usable.

Ray
 
planet4ever said:
A 24 kWh total battery capacity with 10% reserved (unusable) makes sense to me, and leaves us with 21.6 kWh usable.
Right, exactly. A number around 21kWh is quite plausible.

I don't have an explanation for the readouts mogur is getting, although I would like to, but I believe that unusable pack capacity is about 12%. This is somewhat speculative, but looking at the SOC readouts and other data, it's possible that the pack is represented by 320 SOC points (20 + 281 + 19) and 39 SOC points (20+19) are not usable.
 
How do you guys account for that 27kwh number that comes up in the dealer's scan tool?

I think evnow should just buy a module at the dealership and put us out of our misery. He's rich anyways..
 
I don't believe that the charger efficiency is anywhere near that low, at least at 240V... Look at the commercial 3.3Kw chargers that are available for EV applications: The lowest I could find was 84 percent. The highest was 90. (This again is at 240 - they are all significantly lower at 120.) Splitting the difference - since we are all guessing at this point - seems to be a good estimate of what is in the Leaf unless we can find the specific make and model and trace back that information from the manufacturer...

planet4ever said:
Which proves? My calculator says 0.82 * 12.67 = 21.87. That's a lot closer to 21 than to the 24 you seem to be insisting on, mogur. A 24 kWh total battery capacity with 10% reserved (unusable) makes sense to me, and leaves us with 21.6 kWh usable.
 
mogur said:
Look at the commercial 3.3Kw chargers that are available for applications such as the Leaf: The lowest I could find was 84 percent. The highest was 90.


So, 87% then (your number) multiplied by 26.67kWh (your number) is 23.2026.

Still not 24.
 
TonyWilliams said:
So, 87% then (your number) multiplied by 26.67kWh (your number) is 23.2026.

Still not 24.
Volt's pack is 16kWh and the Prius PHEV will have 5.2kWh. What is their usable battery capacity, perhaps 8 and 2.5kWh respectively? It would be foolish for Nissan to give us access to 95% of the pack (another infamous Mark Perry quote).
 
I think that a less than .8kw difference certainly falls in the category of statistical insignificance... And 23.2026 is much closer to 24 than to 21... The bottom line, though, is that none of us know for sure what it really is...

TonyWilliams said:
mogur said:
Look at the commercial 3.3Kw chargers that are available for applications such as the Leaf: The lowest I could find was 84 percent. The highest was 90.

So, 87% then (your number) multiplied by 26.67kWh (your number) is 23.2026.

Still not 24.
 
Bassman said:
The numbers Nissan reported to EPA for their mpg rating was 24KWHrs. So It should be 24 KWHrs.
Yes, most definitely. Wouldn't this imply ~ 3 miles/kWh for the EPA cycle then? That's quite low. Even with 21kWh, I'm getting ~ 3.5kWh. I don't think that they drove to turtle during the cycle then or did they?
 
mogur said:
I think that a less than .8kw difference certainly falls in the category of statistical insignificance...
Speaking of statistical significance, how many owners have tried to measure available pack capacity, and how often?
 
The whole 24kWh vs. 21kWh debate is very entertaining, but it's been chewed to death in other threads (to little conclusion I might add), and has NOTHING to do with calculating real world range using either speed or the mpk number the car gives us...which is the topic of this thread.
 
mogur said:
Look at the commercial 3.3Kw chargers that are available for EV applications: The lowest I could find was 84 percent. The highest was 90. (This again is at 240 - they are all significantly lower at 120.)
None of those efficiencies are counting the power it takes to run the cooling pumps during charging.

Look at what happens to a Tesla Roadster when you charge at 120V - charging efficiency drops in half because of the static charging overhead. Ouch!
 
Between the TED I have on my EVSE circuit and the data from the Blink, it is pretty easy to get comprehensive data on a regular basis. I've run my down to dead three times now to collect data on a number of variables...

surfingslovak said:
mogur said:
I think that a less than .8kw difference certainly falls in the category of statistical insignificance...
Speaking of statistical significance, how many owners have tried to measure available pack capacity, and how often?
 
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