Is my capacity really this low?

[Computerizer]

Every day this week I have driven the same route, 24.6 miles. Each morning before unplugging, I request a Carwings update and it shows I'm at 83% charge. When I get home every day, it says I'm at 33% charge. So I'm using 50% of my capacity to drive 24.6 miles. It also says that on each day I use an average of 8.0 kWh to make this round trip. Note that it has been around 34 degrees, I drive in ECO with the CC on Auto at 66 degrees, seat and steering wheel heaters on, on moderately hilly roads at around 50-55 mph, and other roads that aren't as hilly but only 35-40 mph. Battery temp is always 4 bars. My LEAF is just over a month old.

Assuming that these numbers from Carwings are at least reasonably accurate (the economy and distance traveled does match what the car says), this leads to a couple of concerning conclusions:

First, since I'm using 50% of my capacity to go 24.6 miles, it seems that my maximum range under these conditions is 49.2 miles! Yikes!

Second, apparently 50% of my capacity is equal to about 8.0 kWh. That means my full capacity right now is only 16.0 kWh! That seams to be pretty low, even for 4 battery bars, for a brand new LEAF, doesn't it? Or is Carwings really off the mark?

 

[LEAFfan]

Every day this week I have driven the same route, 24.6 miles. Each morning before unplugging, I request a Carwings update and it shows I'm at 83% charge. When I get home every day, it says I'm at 33% charge. So I'm using 50% of my capacity to drive 24.6 miles. It also says that on each day I use an average of 8.0 kWh to make this round trip. Note that it has been around 34 degrees, I drive in ECO with the CC on Auto at 66 degrees, seat and steering wheel heaters on, on moderately hilly roads at around 50-55 mph, and other roads that aren't as hilly but only 35-40 mph. Battery temp is always 4 bars. My LEAF is just over a month old.

Assuming that these numbers from Carwings are at least reasonably accurate (the economy and distance traveled does match what the car says), this leads to a couple of concerning conclusions:

First, since I'm using 50% of my capacity to go 24.6 miles, it seems that my maximum range under these conditions is 49.2 miles! Yikes!

Second, apparently 50% of my capacity is equal to about 8.0 kWh. That means my full capacity right now is only 16.0 kWh! That seams to be pretty low, even for 4 battery bars, for a brand new LEAF, doesn't it? Or is Carwings really off the mark?

The heater plus the cold temps is really going to lower your range. What's your m/kW h from the dash?

 

[Shaka]

Also remember that the 50% is just an estimate... you could be at the top-or-bottom range of the exact number of bars you display. Someone showed me a few weeks ago a chart (can't find it right now) that explains that the percentage that carwings shows is just a guess .. accurate only within about 8% because it is just a faction, masquerading as a % ... that is how it was explained to me!

 

[TonyWilliams]

Your 50% calculation of battery use is grossly inaccurate.

CarWings only reports in 1/12 segments of capacity, or 8.33% each. So, if you happen to pop over to the next threshold that displays a fuel bar, another 8.33% gone.

Plus, a fuel bar does not equal 8.33% of usable battery. So, the math doesn't work that way.

 

[Computerizer]

Also remember that the 50% is just an estimate... you could be at the top-or-bottom range of the exact number of bars you display. Someone showed me a few weeks ago a chart (can't find it right now) that explains that the percentage that carwings shows is just a guess .. accurate only within about 8% because it is just a faction, masquerading as a % ... that is how it was explained to me!

Okay, that makes sense. Here I thought it was nice that Carwings also showed a percent instead of just the graphic with the bars... ugh.

 

[surfingslovak]

Okay, that makes sense. Here I thought it was nice that Carwings also showed a percent instead of just the graphic with the bars... ugh.

Yes, many owners think so when they get a LEAF, and some never learn any better. Consider yourself a member of the club now. There are many ways to gauge the performance of the car and the battery. One of them was discussed in an earlier thread. The gist of it is that the charging time display can be used in lieu of an SOC meter. Unfortunately, like so many instruments on the dash, it's not entirely reliable. What we know now is that one hour on 120V equals 11 Gids, which is constant, and doesn't seem to change. When properly calibrated, the charging time display on a new car will go from 0 to 25 hours. Have a look at this Google doc as well, perhaps it will help.

 

[Computerizer]

Thanks for the spreadsheet, that's helpful. I'm going from 10 bars after an 80% charge timer down to 4 bars, so my guess is that I'm probably only going from 80% to 40%-ish. The dash says 3.1 mi/kWh (which coincides with Carwings, remarkably). If I'm using 40% and 8.0 kWh, that makes the total capacity come out to 20 kWh which makes a lot more sense.

I've been searching around, but I haven't yet found: Is there a chart or formula somewhere for estimating temporary capacity loss due to low ambient temperatures?

Thanks!

 

[camasleaf]

I drive in ECO with the CC on Auto at 66 degrees, seat and steering wheel heaters on

66 ? Since october the heat was never set higher than 61F :lol: .

If you have on defog in auto the heater will pull a lot of power. I keep it at 61, recirculation to feet, and only push defog ON when needed and OFF when done. But if you only need 24.5 miles a day, do not worry about it.

Still, it is good to learn how to maximize you range, ... sooner or later you are going to need to use those techniques .

And make sure your tires are at 40PSI.

 

[LEAFfan]

Thanks for the spreadsheet, that's helpful. I'm going from 10 bars after an 80% charge timer down to 4 bars, so my guess is that I'm probably only going from 80% to 40%-ish. The dash says 3.1 mi/kWh (which coincides with Carwings, remarkably). If I'm using 40% and 8.0 kWh, that makes the total capacity come out to 20 kWh which makes a lot more sense.

I've been searching around, but I haven't yet found: Is there a chart or formula somewhere for estimating temporary capacity loss due to low ambient temperatures?

Thanks!

3.1 X 17 (80% charge) = about 51 miles to Turtle. 3.1
X 21 (100% charge)= about 63 miles to Turtle.

 

[Computerizer]

66 ? Since october the heat was never set higher than 61F :lol: .

The wife wants it at 72; I want it off. This is a compromise. As you said, I'm going only 25 miles a day so I'm not in danger of running out.

Still, it is good to learn how to maximize you range, ... sooner or later you are going to need to use those techniques .

Actually 3 days after we bought the LEAF we went on a trip that is normally 93 miles in an ICE on the freeway. We took backroads, no heat except occasional defrost, made people behind us mad by driving slow, etc., but did do a quickcharge to 80% about 1/3 of the way there. In the ICE it would have taken 2 hours -- it took us 5 hours. But it was nice scenery! On my normal commute, I don't worry too much about it and drive a little more aggressively, sometimes even passing grannies driving ICEs that are too slow.

 

[surfingslovak]

I've been searching around, but I haven't yet found: Is there a chart or formula somewhere for estimating temporary capacity loss due to low ambient temperatures?

Yes, it's 1% for each 4F/2C below 70F/20C, and it's listed in the fine print below the range chart.

 

[Computerizer]

Yes, it's 1% for each 4F/2C below 70F/20C, and it's listed in the fine print below the range chart.

Ah, I see it there now. So at 34 degrees I'm 9% below the max (of 21 kWh), so I've got around 19.1 kWh usable right now -- and at 3.1 mi/kWh my 100% range to turtle is 59.2 miles, or 47.4 miles on an 80% charge.

I wish there were flatter roads between my house and work...

 

[edatoakrun]

="Computerizer"...Assuming that these numbers from Carwings are at least reasonably accurate (the economy and distance traveled does match what the car says)...

Congratulations. You have learned how to look at the CW energy use data, which already puts your capabilities ahead of several of those self-appointed LEAF experts who have offered you their opinions.

I assume you may be reporting that the dash m/kWh matches your CW report for the same distance driven?

Keep tracking your CW data, and I think you will probably understand why both those identical numbers may be incorrect, and the m/kWh on your center Nav screen (which does accurately represent odometer car miles/CW kWh use) could also be suspect. Here are a couple of threads explaining more:

http://www.mynissanleaf.com/viewtopic.php?f=31&t=5423" onclick="window.open(this.href);return false;

http://www.mynissanleaf.com/viewtopic.php?f=31&t=9064" onclick="window.open(this.href);return false;

="Computerizer"...Ah, I see it there now. So at 34 degrees I'm 9% below the max (of 21 kWh), so I've got around 19.1 kWh usable right now -- and at 3.1 mi/kWh my 100% range to turtle is 59.2 miles, or 47.4 miles on an 80% charge.

Well, that approximation may not be too far off, but since no one has accurately determined the "max" charge (the kWh available from "100%" to stop) at any temperature, nor isolated the effects of temperature variation on that "max" battery charge, or the effects of varying temperature on driving efficiency, you are really just getting a rough "guesstimate", if you limit yourself to the range chart.

="Computerizer"...I wish there were flatter roads between my house and work...

Actually, ascents and equivalent offsetting descents have relatively little effect on your total range. This is where the range chart shows its largest divergence from reality.

Take a look at the multiple range test results reported in detail in the second thread I posted above, the longest rip from "100%" to ~VLBC resulting in:

6/17(12) capacity test results:

110.9 miles to VLB, 112.7 in total, by the odometer, with close to 6,000 ft of ascent and descent.

CW: 109.9 (~2.5% under-report) total miles, at 6.3 m/kWh, 17.5 kWh used from 100% to about the same point, slightly past VLBW...

 

[LEAFfan]

Ed, I can't speak for your dash m/kW h, but mine is extremely accurate. When the car was new I drove 84 miles with a 4.0 reading many times. When I hit 5.0, I drove over 100 miles. I've never had ANY software updates.

 

[edatoakrun]

Ed, I can't speak for your dash m/kW h, but mine is extremely accurate. When the car was new I drove 84 miles with a 4.0 reading many times. When I hit 5.0, I drove over 100 miles. I've never had ANY software updates.

Wasn't your car in the Phoenix range test?

Which LEAF was yours?

http://www.mynissanleaf.com/wiki/index.php?title=Battery_Capacity_Loss#Range_Test_on_Cars_with_Battery_Capacity_Loss" onclick="window.open(this.href);return false;

As you can see, the 12 Arizona LEAFs, driven in controlled conditions, reportedly varied in m/kWh performance from 3.7 m/kWh to 4.4 m/kWh.

Assuming this large variation of efficiency was not reporting error, it seems very unlikely that very much of this large variation can be explained by the variations in driver efficiency alone. Unfortunately, none of the drivers reported their Carwings data, including the regenerated kWh, which would have largely answered the question of how great the variation in driver efficiency was, as the most efficient drivers would have produced less regen kWh, as reported by (and is only available from) Carwings.

So, the other likely explanations would seem to have to be either large variations in drive train efficiency, or far more likely IMO, error in many or all of the tests LEAF's reporting of total kWh use, which would have showed up in the Carwings total kWh use, and in m/kWh numbers, in results identical to the 12 LEAFs' individual dash reports.

The reason I believe the NAV screen m/kWh and not the Dash m/kWh reflects the "accurate" report of my (quite possibly inaccurate) CW kWh use report is that it can be mathematically proven.

The dash/kWh report on my car (and as reported by many others) matches the Carwings m/kWh report in every instance.

But the CW report of miles driven is calculated using an underestimate of miles driven of ~2.5% (stock tires with minimal tread wear) as compared to both my dash odometer which I have confirmed to be quite accurate by checking it against google map distances.

So when you drove "84 miles with a 4.0 reading" on your dash, I expect your nav screen would have given you the more accurate account of whatever you LEAF was reporting as kWh use, whether accurate or not, of 4.1 m/kWh.

And Carwings (if you had it updated and used it) would have reported this trip as ~20.5 kWh used, to drive ~82 miles, at the same 4.0 m/kWh that your dash showed.

 

[surfingslovak]

The cars in the Phoenix test were driven in cruise-control mode at 62 mph ground speed (per GPS). Aside from a short drive to the freeway and the turning point, the driver would not even have her or his foot on the accelerator pedal. What differences in driver efficiency could there be? And as an aside, this was one of the salient points raised by Mark Larsen during his Transport Evolved interview. "Your mileage will vary" and "driver efficiency"? I would really like to understand how anyone can say that given Tony's test protocol for the Phoenix range test. I believe that it was designed to take most factors out of the equation, including the driver.

 

[edatoakrun]

The cars in the Phoenix test were driven in cruise-control mode at 62 mph ground speed (per GPS). Aside from a short drive to the freeway and the turning point, the driver would not even have her or his foot on the accelerator pedal. What differences in driver efficiency could there be?...

Well, we will never know now, since the regen figures for the test LEAFs were never observed.

I use cruise control infrequently, but don't relatively small changes is grade initiate some regen in cruise control, just as they will a human driver actively maintaining a near-constant speed?

Obviously, any variations in the efficiency of the individual LEAFs drivers, human or otherwise, would have been picked up in the CW regen report. I doubt they would have varied by very much between the 12 LEAFs, which is precisely why I think errors in the dash m/kWh reports are the "prime suspect" in the anomalies in the Phoenix test results.

And why I think it may not a good idea to try to use any kWh use report generated by a LEAF to definitely determine available battery capacity, as many attempt, until Nissan produces a solution for the "gauge error" problem.

 

[surfingslovak]

Sure. Hopefully, there will be more range tests, and not just organized by Tony. That way, a different or better protocol could be experimented with, if the organizer so wishes. The test, the way it was originally planned anyway, was to drive all the cars over the same roads and at the same speed until they hit turtle. Then compare the distances they have covered. Simple, relevant and poignant. Everything else, including data collection from the dash and CW, could be considered superfluous. While I agree that it might be beneficial to analyze the results later, others would say that a range test by itself is pointless, and everybody should just do a bench test, much like Nissan has done in Casa Grande. You can't make it right by everyone. I can attest that the Phoenix test was very taxing logistically, and I'm surprised that it ended as well as it did. As I said, hopefully there will be an opportunity or two to improve on it in the future.

 

[kubel]

66 ? Since october the heat was never set higher than 61F :lol: .

In my experience, it doesn't matter what I set my heater to, the air that comes out in eco mode is always barely lukewarm. In the single digits, the car will not heat up in eco mode. It just keeps the cabin temp above freezing. I need to get a thermometer and put it in the car somewhere to measure the real cabin temperature and compare it to the indicated setting.

 

[Computerizer]

In my experience, it doesn't matter what I set my heater to, the air that comes out in eco mode is always barely lukewarm.

In the mid-20s F here it does get pretty warm after about 5 minutes while in ECO, and I have no problem with it after that.