Range Chart

[TonyWilliams]

To commemorate our first known battery capacity reductions, I've compiled an 85% capacity chart. That means there are 11 of the 12 battery capacity segments (number 14 in the photo) illuminated to the right of the "fuel bars" (number 13 in the photo):

The data is now based on 17.85kWh of useable capacity. Interesting to note that we will soon have Low Battery Warning coming on at 2 fuels bars, instead of one, as capacity decreases.

Unfortunately, Nissan choose not to follow basic instrument standards, so each segment does not equal the same amount. When only 10 capacity segments are illuminated, for instance, that will be 23% loss, for 77% capacity:

 

[TonyWilliams]

LEAFfan wrote:
Speaking of accurate, you should redo all your charts and make them realistic instead of using just set speeds. When someone takes a 'trip' somewhere, they just don't start out at your set speed nor do they end it at your set speed. More accuracy with the m/kW h would be realized by making the 'whole' trip with those set speeds included. I drove mostly freeway speeds today, with a little before and after and exceeded your chart numbers by quite a bit even though almost all of it was freeway speeds.

I don't have any plans to "redo" charts to meet your expectations. The correct way to use a chart like this is to apply the correct miles/kWh for the portion of the trip you are calculating.

Please refer to these posts:

http://www.mynissanleaf.com/viewtopic.php?p=124044#p124044" onclick="window.open(this.href);return false;

http://www.mynissanleaf.com/viewtopic.php?p=122618#p122618" onclick="window.open(this.href);return false;

http://www.mynissanleaf.com/viewtopic.php?p=122625#p122625" onclick="window.open(this.href);return false;

 

[bernie82]

Will driving in ECO mode on freeways effect your charts, Tony?

 

[TonyWilliams]

Will driving in ECO mode on freeways effect your charts, Tony?

In short, no. Going down the flat freeway at 60mph will get the same economy in D or ECO.

As you may know, ECO will reduce the climate control, however the charts are based on no climate control. That variable is therefore eliminated.

ECO may improve your around town economy, but the chart compensates for that simply by using the correct miles/kWh.

ECO mode will increase your regeneration, assuming your battery isn't near 100%, or you don't panic stop, or a few other variables which will decrease regeneration.

 

[bernie82]

Looking at your 100% chart I notice that the average miles per bar at at a specified speed increases as we get deeper into the batteries. for example, at 10 bars at 60 MPH, the chart indicate that the leaf can travel 61 miles or 6.1 miles per bar. When the Leaf is down to 3 bars at 60 MPH the chart indicates that the leaf can travel 30 miles or 10 miles per bar. Is there an explanation for this phenomena?
Again, relating to the chart, does the projected range for a given speed mean to Turtle mode or to the first low battery warning?

 

[TonyWilliams]

Looking at your 100% chart I notice that the average miles per bar at at a specified speed increases as we get deeper into the batteries. for example, at 10 bars at 60 MPH, the chart indicate that the leaf can travel 61 miles or 6.1 miles per bar. When the Leaf is down to 3 bars at 60 MPH the chart indicates that the leaf can travel 30 miles or 10 miles per bar. Is there an explanation for this phenomena?

I'm not sure what you're seeing. Part of the issue that might not be obvious is that the 1st fuel bar does not stay lit until turtle.

I'm looking at the chart and there's not 10 miles per bar at 60mph. There's 30 miles of range left in the 3rd bar, and six miles later, the second bar then has 24 miles, and then nine miles later, the 1st bar has 15 miles of range, and only three miles the Low Battery Warning comes on concurrent with the 1st bar still staying illuminated. 12 miles of range remain.

During this time, eventually the 1st bar turns off, but we don't care, because we aren't using the fuel bars for range calculations any more. Stay now with the battery warnings. It might make more sense by looking at the 85% (15% degradation) chart, you'll see that LBW can come on with two fuel bars. With 50% degradation, there may be 4 or 5 fuel bars lit up when the LBW comes on. That's because the fuel bars are variable to the total available capacity, but the battery warnings (LBW and VLB) are indexed to a specific amount of energy measured in "Gids" (calculated battery watt/hours).

Eight miles after LBW came on, the Very Low Battery comes on with four miles remaining. Then Turtle mode will come on. Then the car will stop shortly thereafter.

At 3.9 miles per kWh or about 60mph on flat terrain:

Fuel Bar 3- 30 miles range remaining - 6 miles until fuel bar 2
Fuel Bar 2- 24 miles range remaining - 9 miles (the "fattest" fuel bar)
Fuel Bar 1- 15 miles range remaining - 3 miles until LBW, but stays on
LBW------ 12 miles range remaining - 8 miles until VLB
VLB------- 4 miles range remaining - 4 miles until Turtle
Turtle----- 0 miles range remaining - ------------------

Again, relating to the chart, does the projected range for a given speed mean to Turtle mode or to the first low battery warning?

All the projected range data is to Turtle. The first Low Battery Warning still has 17.4% of the available energy in the battery. No "reserve" is implied.

 

[bernie82]

Thanks for the great explanation, Tony. I completely understand.

 

[RegGuheert]

In another thread you wrote:

I'm probably over 10%, and I estimate 13% actual performance reduction.

Tony, your current range chart says this:

Battery Degradation: Subtract 2% from range for every 10,000 miles/15,000 km on the car

While that may be accurate for some LEAFs, it may be too optimistic for others. For instance, it seems your chart now overestimates the range of your 2011 LEAF by about 11%.

I'm wondering if different wording might be appropriate at this time. Perhaps there could be a mention that there is also a calendar component to capacity degradation as well that seems to range from 0%/year to about 15%/year for the first year depending on climate. (Perhaps the note on the chart with one missing bar could have similar but adjusted wording once we learn more about degradation in later years.)

The reason I've been thinking about this is we are planning a 75-mile trip for my wife today and we simply do not know the status of the battery in our LEAF which was built almost exactly one year ago. At first it seemed tight but doable, but now it is raining and there should be thunderstorms during her drive, so the uncertainty about the battery capacity has caused us to switch her to the hybrid.

Thoughts?

 

[camasleaf]

there should be thunderstorms during her drive, so the uncertainty about the battery capacity ...

Raise the antenna higer, catch the lightning and the range will not be a problem anymore :lol: . It is SQCDC (Super Quick Charging)!

 

[QueenBee]

Raise the antenna higer, catch the lightning and the range will not be a problem anymore :lol: . It is SQCDC (Super Quick Charging)!

It's certainly quick but the average lightning strike only consists of 550 watts delivered in milliseconds so you'd need about 40 strikes to charge up a LEAF from empty

 

[RegGuheert]

Raise the antenna higer, catch the lightning and the range will not be a problem anymore :lol: . It is SQCDC (Super Quick Charging)!

It's certainly quick but the average lightning strike only consists of 550 watts delivered in milliseconds so you'd need about 40 strikes to charge up a LEAF from empty

Are you sure?! I've always figured the power level for lightning was right around 1.21 GW! :lol:

 

[NYLEAF]

Maintaining the necessary 88 MPH to charge via lightning will result in a significantly reduced Mi/kWh, making the whole exercise a bit pointless.

 

[TonyWilliams]

Well, the chart notes were obviously written before we knew / believed that these cars would take big hits to range. Having said that, a chart is not a great place to explain HOW it happened. Nissan said / says 70-80% remaining in 100,000 miles, so that's the basis for 2% loss per 10,000 miles.

Obviously, any car with 15% capacity reduction would not use a 2% reduction. There are PLENTY of cars that meet the 2% or less per 10,000 mile guideline, including one with over 40,000 miles.

What wording change would you suggest?

In another thread you wrote:

I'm probably over 10%, and I estimate 13% actual performance reduction.

Tony, your current range chart says this:

Battery Degradation: Subtract 2% from range for every 10,000 miles/15,000 km on the car

While that may be accurate for some LEAFs, it may be too optimistic for others. For instance, it seems your chart now overestimates the range of your 2011 LEAF by about 11%.

I'm wondering if different wording might be appropriate at this time. Perhaps there could be a mention that there is also a calendar component to capacity degradation as well that seems to range from 0%/year to about 15%/year for the first year depending on climate. (Perhaps the note on the chart with one missing bar could have similar but adjusted wording once we learn more about degradation in later years.)

The reason I've been thinking about this is we are planning a 75-mile trip for my wife today and we simply do not know the status of the battery in our LEAF which was built almost exactly one year ago. At first it seemed tight but doable, but now it is raining and there should be thunderstorms during her drive, so the uncertainty about the battery capacity has caused us to switch her to the hybrid.

Thoughts?

 

[RegGuheert]

What wording change would you suggest?

How about something like the following:

Battery Degradation: With all 12 capacity bars remaining, the range of your LEAF should be between 86% and 100% of the value given by this chart. If you have measured the capacity of your LEAF battery using either an instrument or a range test, you can apply the appropriate factor to get an accurate range. Otherwise, you should use 86% to get a conservative estimate of range.

The point is that there are cars out there covering the full range of the first bar. For those of us who have not determined the range of our vehicles, 2%/10,000 miles could be way low.

Personally, we don't know the capacity of our car, but there are some signs of reduced capacity, including a prediction of 3.5 hours to charge from 80% on L1. Most LEAFs indicate 4 hours.

 

[surfingslovak]

Personally, we don't know the capacity of our car, but there are some signs of reduced capacity, including a prediction of 3.5 hours to charge from 80% on L1. Most LEAFs indicate 4 hours.

Reg, that's a fair point, but I wouldn't read too much into it. I have seen 3.5 on my Leaf as well, and my Gid readings are within 3% of nominal these days. A range test would provide additional insight, but please keep in mind that in my experience the accuracy of a well-executed range test is between 2 to 4%. Not everything you measure and see is permanent battery degradation, there are many other factors that play into this. The best way to determine capacity loss between 2 to 8 % is to charge the car to full, please use the trickle cord for the 80 to 100% portion to make sure that the charging time display is correct.

There is an algorithm in the car that attempts to recalculate the remaining time to charge every time you plugin. This algorithm does not work very well, and if you didn't complete a full charge with the trickle cord, the display could have an offset (or error). Proceed to use the car as you would every day, no need for a range test. Eventually, make a point to bring it down to the very low battery warning or to turtle.

With minimal degradation, the charging time display will show 25 hours before you turtle and 23 hours at the time of the very low battery warning. If your battery lost some capacity, you will see lower numbers, perhaps only 24 or 23 hours at turtle and 22 hours at the very low battery warning. Each hour corresponds to about 4% of battery capacity, and this should give you a better idea. Personally, I would just wait for Leafscan or buy an inexpensive version of the Gid meter (I hear that several might be coming).

 

[RegGuheert]

Thanks for the detailed description of that charging GOM. It is very helpful to me!

Personally, I would just wait for Leafscan or buy an inexpensive version of the Gid meter (I hear that several might be coming).

Yes, I'm holding out for a LEAFscan.

Still the point remains: The range chart is awesome, particularly if you know accurately your battery capacity. But we do not know that nor do we know the full history of our car, since it was a demo. As such, all we really know is that we still have 12 capacity bars. Given the ambiguity on our battery capacity, we will choose to err on the pessimistic side or risk getting stranded.

 

[surfingslovak]

Still the point remains: The range chart is awesome, particularly if you know accurately your battery capacity. But we do not know that nor do we know the full history of our car, since it was a demo. As such, all we really know is that we still have 12 capacity bars. Given the ambiguity on our battery capacity, we will choose to err on the pessimistic side or risk getting stranded.

Yes, that's true, and you would be well advised to estimate what the usable capacity was. Tony wrote up really detailed range test instructions a little while ago. If you wanted to use the charging time display, and didn't wish to run the car down to LBW, an alternative approach is to stop at 50% charge and extrapolate total capacity from there. Not entirely accurate, but it will give you some idea, where your vehicle falls in terms of battery capacity.

If you are concerned about getting stranded, you could establish some checkpoints to see how you are doing and have a plan B in case you were not going to make it. This could be as simple as getting off the freeway and taking an alternate route or level 2 opportunity charge somewhere convenient.

 

[JPWhite]

Thanks for the detailed description of that charging GOM. It is very helpful to me!

Personally, I would just wait for Leafscan or buy an inexpensive version of the Gid meter (I hear that several might be coming).

Yes, I'm holding out for a LEAFscan.

Still the point remains: The range chart is awesome, particularly if you know accurately your battery capacity. But we do not know that nor do we know the full history of our car, since it was a demo. As such, all we really know is that we still have 12 capacity bars. Given the ambiguity on our battery capacity, we will choose to err on the pessimistic side or risk getting stranded.

As time goes by, usinga chart is only necessary when planninga trip to a new location for the LEAF. As time goes by one starts measuring destinations in 'bars' and know intuitively if you can make it or not based on the current charge. It gets easier, trust me

 

[lincomatic]

Tony, are the SOC values at the fuel bar transitions hard coded in the car, or do they change as the car ages?

I've been having a lot of trouble with range on my car lately, despite having gone to the dealer for my useless annual battery checkup, where
the battery health status sheet they gave me claimed my battery was perfect. I think they're hiding something.
My 100% SOC has degraded over 11K miles from avg ~273 (I never got 281) when new to ~266. Yesterday, it charged to only 263, my lowest yet.
I used to easily be able to do a trip to my friend's house RT 68mi. Last trip, I had to pull off the freeway and literally roll at ~15 mi for the last 9 miles,
almost hitting turtle when I got home. This time, with my SOC meter in the car, I drove extra conservatively, and almost definitely would not have made
it home, had there not been a 4th of July traffic jam on the freeway.

Your chart shows a transition from 2->1 fuel bar at SOC = 73. Yet, when I arrived home last night, the instruments where showing 2 fuel bars left at SOC = 59, and 9 on the GOM. That's a pretty big discrepancy, but it correlates well with what I've been seeing with GOM/fuel bar levels recently .. I'm getting much lower GOM values vs fuel bars than I'm accustomed to lately.

Is it possible that there needs to be a scaling factor to calculate SOC @ fuel bar transitions, based on the 100% starting SOC?

Oh, and I don't have enough data to verify this, but it *seems* like the car eats up the SOC faster when I top up the car to 100% and then jump immediately into the car for a long trip than when I charge overnight, and then drive it after it's been sitting for several hours.

 

[TonyWilliams]

Your chart shows a transition from 2->1 fuel bar at SOC = 73. Yet, when I arrived home last night, the instruments where showing 2 fuel bars left at SOC = 59, and 9 on the GOM. That's a pretty big discrepancy, but it correlates well with what I've been seeing with GOM/fuel bar levels recently .. I'm getting much lower GOM values vs fuel bars than I'm accustomed to lately.

Is it possible that there needs to be a scaling factor to calculate SOC @ fuel bar transitions, based on the 100% starting SOC?

Oh, and I don't have enough data to verify this, but it *seems* like the car eats up the SOC faster when I top up the car to 100% and then jump immediately into the car for a long trip than when I charge overnight, and then drive it after it's been sitting for several hours.

Lots of good observations. First, even including GoM data makes me cringe. It has nothing to do with the data on my chart, nor is it related to fuel bars. The only, singular thing that it does with absolute consistency is display "---" with VLBW, which is also directly linked to 24 Gid (24*75=1.8kWh available to you stored in the battery). Since you can just as easily observe the Gid count or percentage, and hear and see the various warnings, again there is really no reason for the entire GoM quadrant of the dash. Put a smiley face sticker there.

The fuel bars are NOT directly linked to the store battery energy (Gid), but the battery warnings are. That's why the warnings always supersede whatever battery bar might be displayed, to determine range. Your observations of variations are indeed consistent, exempt for (again) battery warnings.

So, in summary, you already have a Gidmeter / ScanGauge / LEAFscan, therefore I recommend NOT using any part of the fuel gauge or GOM. The range chart is fully capable of being used without any of those instruments, provided you you can display Gid count or %.

The top fuel bar always goes away quicker than the others for me, and the chart reflects that. Again, try not to rationalize what we know to be quite irrational. Gid count/% and the two battery warnings are great indicators to use with the chart or various chart based apps for calculating range.