12% capacity loss in 9 months is "normal"

[Weatherman]

Of course, I also ran the range test where I...

1) Charged the car to 100% and let it sit, plugged in, for another six hours to ensure it would do any cell balancing if needed.
2) Ran the car on cruise control at 60 mph for 20 miles and 65 mph for 40 miles, only slowing down for on-ramps and off-ramps, and reached LBW at 62.2 miles. Temp was 70 degrees, flat terrain and calm winds.
3) The car showed a reading of 3.9 kWh/mile for the trip

I didn't extend the test all the way to VLBW, but ran at slower speeds, past LBW, for an additional 8 miles (a little over 70 miles, total).

So, it begs the question...

Is 62.2 miles from 100% full to LBW, cruising along at a steady speed of around 63 mph, at 70 degrees, calm winds and flat terrain, and showing 3.9 kWh/mile considered "normal"?

 

[Weatherman]

Full charge rate is 240 * 16 or 3840 Watts. Without a meter to measure your battery after a full charge u are really flying blind

Remember... The LEAF has a 3.3 kW charger, so you aren't getting 3.84 kW delivered to the battery.

 

[edatoakrun]

Why do you say that this is an unexpectedly short charge time? That's a 16 amp L2, right?

When I do the math for 5.33 hours (or do you mean, 5 hours, 33 minutes?) 1 get about 17.4 kWh, 16 amp at 85% efficiency. the tapered charge rate at the end probably means you actually got less than this.

But without knowing more, what period of time, and at what charge rate, occurred at the end of charge, I don't see how you can figure out much, from the just the total time reported.

Check your CW reports for the calculated kWh used, for the same drive.

Ok, let’s run some numbers...

Assume that LBW is 49 gids (somewhere between 3.7 and 3.9 kWh), and I ran it a couple of miles past that, so lets say 3.5 kWh was left.

Let's also assume that the charger runs at full 3.3 kWh capacity for 5.33 hours (five hours, 20 minutes) to charge it back to 100% (probably not be true of the charge rate drops off as it approaches 100% full). So let's say 17.3 kWh to charge back to 100%.

So, conservatively, I have 3.5 kWh + 17.3 kWh for a full charge. That would be 20.8 kWh. If you assume 80 kWh per gid, that would be 260. You'd have to go with a 75 kWh per gid assumption to get 277 gids.

This is, certainly, not as bad as what TickTock is seeing, but is a bit less than I'd expect to see with a four-month-old car with 3,500 miles on it.

I'm going to take it into a local dealer, tomorrow, to see if they can find any defects. My expectation is that they will say nothing is wrong.

Because, almost certainly, nothing is wrong, since almost certainly:

You had between 20 and 21 kWh available, when you started

You had used between 17 and 18 kWh when you got the LBW.

If you "accept"ed CW, you can take a look at your report, and will have much more precise numbers than these, to consider.

 

[Herm]

Is 62.2 miles from 100% full to LBW, cruising along at a steady speed of around 63 mph, at 70 degrees, calm winds and flat terrain, and showing 3.9 kWh/mile considered "normal"?

The experts will chime in, but if you only used 80% (LBW) of 21kWh or a total of 16.8kWh that works out to a projected range of 65 miles, or close enough to normal for our purposes. Thats a 3 day ride on a horse.

Next time slow down to 55mph and pump up your tires to maximum.

 

[Weatherman]

You had between 20 and 21 kWh available, when you started

You had used between 17 and 18 kWh when you got the LBW.

If you "accept"ed CW, you can take a look at your report, and will have much more precise numbers than these, to consider.

Is 20 to 21 kWh the consensus on the usable capacity of the battery?

I see some quotes that it's 80 kWh per gid and people are measuring around 280 gids. That would be 22.4 kWh.

 

[Weatherman]

The experts will chime in, but if you only used 80% (LBW) of 21kWh or a total of 16.8kWh that works out to a projected range of 65 miles, or close enough to normal for our purposes. Thats a 3 day ride on a horse.

Next time slow down to 55mph and pump up your tires to maximum.

Fortunately, I don't need anywhere near the range I'm currently getting, so I'm not going to fret about the end result, not matter how it goes.

I'm doing this exercise out of curiosity more than anything else.

 

[EVDRIVER]

Seeing 22.4 kWh usable on mine at full charge. I have 280 Gids at about 60 degrees. All these charging and driving tests are simply not accurate for measuring anything. I also have no idea why people think cruise control is some sort of control factor. In fact I would bet it is worse in some road conditions as it will use more energy at times.

 

[EdmondLeaf]

Will be great if Nissan will tell as how much capacity we have. GOM is not really indication of miles left. My commute to work used from 3 to 6 bars so that is not accurate too, anyway bar represent 8% capacity (or who knows) and when you really at the bottom every % is important. What is the good reason for "hidden bars" - I am not a small kid that one need to hide very important information from me. I won't run car to 0 for fun of it, but I may because crucial info is missing. My commute is relatively long 32miles without infrastructure, how this is helpful to me and other potential customers that are asking what range I really have?

 

[edatoakrun]

Seeing 22.4 kWh usable on mine at full charge. I have 280 Gids at about 60 degrees. All these charging and driving tests are simply not accurate for measuring anything...

Yes, a range test is only useful for determining range.

Why would any one want to know that...?

 

[DaveinOlyWA]

22.4 is seeable capacity not usable capacity

 

[EdmondLeaf]

Seeing 22.4 kWh usable on mine at full charge. I have 280 Gids at about 60 degrees. All these charging and driving tests are simply not accurate for measuring anything...

Yes, a range test is only useful for determining range.

Why would any one want to know that...?

Range very important for me especially for the bottom bars and "hidden bars"

 

[EdmondLeaf]

22.4 is seeable capacity not usable capacity

is usable somewhere between 20 - 21 kWh (temp related)?

 

[TonyWilliams]

Is 20 to 21 kWh the consensus on the usable capacity of the battery?

I see some quotes that it's 80 kWh per gid and people are measuring around 280 gids. That would be 22.4 kWh.

Here we go..... I knew when 80 was announced as a Gid, this comment would come up over and over. Yes, Nissan says 80, HOWEVER if you use the equipment provided (the dash instruments), it will equal about 75.

When we all have LEAFscans, we will be able to see actual battery capacities, etc. We don't have that yet: 281 Gids times 75 watthours equals 21kWh. NOTE: with LEAFscan, we will observe 80, and therefore measure a higher 22.5kWh (281*80).

Now, as to the capacity, with whatever method you use to determine battery capacity, it is variable with:

1. Temperature - my current rule of thumb is 1% loss per 4F below 70F, and 1% gain per 8F above 70F. A 30F battery would suffer 10%, or 18.9kWh of useable power.

2. Degradation - about 20-30% at 100,000 miles, per Nissan. That number 12 degradation bar won't disappear until 85% of battery capacity. At a full charge, regardless of the amount of degradation, all 12 fuel bars will be displayed, and an SOC gauge (with a LEAFscan) will show 100% (a Gidmeter does not display State Of Charge).

3. Cell imbalance

4. Failure or one or more cells

 

[Weatherman]

22.4 is seeable capacity not usable capacity

If that's the case, then I guess what I'm seeing with my car is normal, after all.

(just suffering from stupid "battery degradation anxiety")

 

[TonyWilliams]

22.4 is seeable capacity not usable capacity

is usable somewhere between 20 - 21 kWh (temp related)?

Mostly, yes.

See above post and notes in the range chart.

 

[TonyWilliams]

Seeing 22.4 kWh usable on mine at full charge. I have 280 Gids at about 60 degrees. All these charging and driving tests are simply not accurate for measuring anything. I also have no idea why people think cruise control is some sort of control factor. In fact I would bet it is worse in some road conditions as it will use more energy at times.

That seems a bit silly as stated, so maybe you can clarify. How do you determine 22.4kWh? Is it just Gid * 80 ?

If so, we really need to get this clarified. I recommend "actual" and "useable" to differentiate between the 80 and 75 values of Gids using their respective instruments.

EDIT: if you used 22.4kWh as your battery capacity based on the correct actual value of 80 watt hours per Gid, you absolutely will not drive at 4.0 miles per kWh (as measured from the drivers dash) and complete 89.6 miles. it is a setup for failure.

At 75 useable Wh per Gid * 281 equals 21kWh, and driving at 4.0 miles/kWh will in fact take you 84 miles.

That's why I'll keep repeating that, because like the original poster and yourself, it is quickly becoming confusing to many.

Cruise control eliminates the human element. Yes, even big expensive airplanes use automation to eliminate the human failures.

 

[DaveinOlyWA]

Contactors to main traction pack open at 4 GID so take 320 Watts out as unaccessible then remove a few% due to heat and we are left with about 21.5 Ks to use

 

[TickTock]

Of course, I also ran the range test where I...

1) Charged the car to 100% and let it sit, plugged in, for another six hours to ensure it would do any cell balancing if needed.
2) Ran the car on cruise control at 60 mph for 20 miles and 65 mph for 40 miles, only slowing down for on-ramps and off-ramps, and reached LBW at 62.2 miles. Temp was 70 degrees, flat terrain and calm winds.
3) The car showed a reading of 3.9 kWh/mile for the trip

I didn't extend the test all the way to VLBW, but ran at slower speeds, past LBW, for an additional 8 miles (a little over 70 miles, total).

So, it begs the question...

Is 62.2 miles from 100% full to LBW, cruising along at a steady speed of around 63 mph, at 70 degrees, calm winds and flat terrain, and showing 3.9 kWh/mile considered "normal"?

I recommend doing Tony's suggestion first. To avoid argument, take it to at least VLBW. Reset the efficiency meter and record it at the end (doesn't matter if you change your speed and efficiency during the test - it will report the total effective efficiency since you last reset it). If you only go to VLBW, you need to add in ~1.6*efficiency (6.4 miles@4mpkwh) for the remaining VLBW to dead. Then compare to the chart in the Nissan Technical Bulletin NTB11-076a (attached). At 4.0mpkWh you should get no less then 76 miles 100% to dead according to Nissan's own publication.

 

[TonyWilliams]

EDIT: here's the way I'd like the data presented so we can eliminate guessing and 20 questions as much as possible:


Checklist before the data collecting run:

1. (your answer) Any changes to car from stock (different tires, bike rack, Texas cattle horns, etc)
2. (your answer) Tire pressures set, heater and air conditioning off, car at 100% charge, cells allowed time to balance
3. (your answer) Gross vehicle weight? 3350 pounds plus operator, passengers, spare tire, bags, concrete, etc
4. (your answer) Route, length, elevation, hills if any, general conditions (dry, concrete/asphalt, etc)
5. (your answer) Assumed or measured battery temp (from LEAFscan tool)
6. (your answer) Ambient air temp
7. (your answer) Gid count at start, if available
8. (your answer) SOC, if available (from LEAFscan)
9. (your answer) Starting total voltage (should be 393.5v from GidMeter or LEAFscan tools)
10. (your answer) Accept CarWings on Nav screen startup by pressing OK

Data to record:

1. (your answer) Outbound steady speed (confirm with cruise control on)
2. (your answer) Outbound observed steady speed miles/kWh from Nav adjusted -0.1
3. (your answer) Inbound steady speed (confirm with cruise control on)
4. (your answer) Inbound observed steady speed miles/kWh from Nav adjusted -0.1
5. (your answer) Miles at Low Battery Warning
6. (your answer) Miles at Very Low Battery
7. (your answer) Overall miles covered to Turtle
8. (your answer) Overall miles/kWh from dash economy display
9. (your answer) Calculated battery useable energy (miles / miles/kWh = battery kWh)
10.(your answer) Ending pack voltage, SOC, and Gid (350v-ish from GidMeter or LEAFscan tools)
11. (your answer) Go to a computer (usually the next day) and report the CarWings kWh and miles used

 

[edatoakrun]

Or, to find your LEAF battery pack's available kWh capacity to a given level of discharge, such as LBW, VLBW, or turtle:

You can just forget about the uncertainties inherent in the gid Calculation, and all the uncertainties and errors in the range chart, as illustrated in the several voluminous posts above, and simply look at Carwings calculated kWh use for the trip(s) taken.

You probably will get a much more accurate calculation, of kWh use.

Of Course, this requires great exertion that many LEAF drivers seem unable to undertake.

You have to "accept" Carwings, and actually look at the results...