Collecting data:Off-the-wall power for turtle to 100% charge

[DaveEV]

when the LEAF is new it has about 21 and a half kilowatt hours. so charging on l2 it 89 or 90 percent efficiency means it will take about 24 kilowatt hours

Your numbers don't add up. Heck - look at the first post of this thread - many reports of significantly higher turtle to 100% readings. Even surfingslovak recorded 24.5 kWh from the same type of Coulomb L2, after 6 months of ownership.

24 kWh * 90% = 21.6 kWh - at 4.5 mi/kWh one would get 97.2 miles before dead.

LEAFer got 20.544 kWh from the wall from turtle to 100%, which at 90% would indicate 18.5 kWh usable.

20.544 / 24 = 85.6% or 14.4% less than new (not 13% and assuming 24 kWh from the wall is new, when it really is 25-26 kWh).

LEAFer got 70.2 mi from 100% to VLBW at 4.5 mi/kWh indicating 15.6 kWh used. Do you really think he had 2.9 kWh remaining in his pack before it went dead? That would be another 13 miles at 4.5 mi/kWh between VLBW to turtle which is unheard of. In reality at 4.5 mi/kWh, there's no more than 6 miles left which would put total miles at 76.2 miles.

76.2 mi / 97.2 mi = 78% range of new. If he had 13% loss he should be able to do 84 miles at 4.5 mi/kWh.

Sorry, I have no idea how you're coming up with range loss ~13% when both my previous calculations match up nearly perfectly.

 

[LEAFer]

Oh - and do you have all the firmware updates on your car? Getting LBW with 2 bars and VLBW with 1 bar doesn't seem right...

Yeah ... my apologies. That portion of the data recording was not very "clean", as I was busy with safely operating the vehicle. I think LBW and VLBW both happened with 1 bar remaining. Not 100% sure at how many miles I lost the final bar.

Software updates: none since July 2011 that I am aware of. At the 1 year check in Jan2012 the paperwork does not list any software updates, but who knows what they did to the car. I have NOT yet had the update for the door-open/power-on warning chime or anything else since Jan2012. In other words, I haven't let the dealer touch the car since Jan2012.

It is indeed surprising that the 12th bar is still there. Have had the 9-bars-80%-charge for many months.

In addition to the 20.544 I am also counting the extra 0.178 a few hours later (after midnight) = 20.722.

The GID count being "high": I don't have a GID meter. The measurement was taken 3.5 months ago with Tony's meter, before the summer heat (!). That June I took two mornings in a row measurements and posted the second one (the first was was slightly worse).

 

[GerryAZ]

LEAFer's data looks a lot like my recent numbers even though I have lost 2 capacity bars.

My charge from turtle to 100% after the September 15th range test took 20.43 kWh after driving 71.8 miles. Estimated charge times were 6:00 @ 240V and 17:00 @ 120V. Actual L2 charging time was 5:27 and dashboard efficiency was 4.2 mi/kWh.

My charge from shutdown to 100% on October 10th after driving 72.2 miles in D mode (21.8 miles total after LBW including 9.0 miles after VLBW) and then running climate control in the driveway to get turtle and then shutdown took 20.12 kWh. Estimated charge times were 6:00 @ 240V and 17:00 @ 120V. Actual L2 charging time was 5:25 and dashboard efficiency was 4.3 mi/kWh.

Since I frequently hit VLBW and always charge to 100% my battery cells probably stay well balanced. This probably contributes to the situation I notice where power circles do not start to disappear until turtle is almost reached and the total distance that I can drive from the loss of the first power circle to shutdown is only about 0.5 mile. The cells being well balanced may also contribute to less charge tapering and shorter charging times.

Gerry

 

[LEAFer]

Interesting info Gerry.

Notice that when I reached home ( 1 mile after VLBW ) I was at 6TB and Est. Time to charge 6:30/18:00. This soon moved to 7:00/19:00, but then took quite a while (heater+A/C+1mile drive) to reach 7:00/20:00. When it did, it still did not show Turtle. So, having seen the change from 19:00 to 20:00 I decided to power-cycle, and that's when Turtle (and "Motor Power Limited" , 7 circles lost) showed up.

IIRC someone reported L1 re-charge estimates as high as 25:00 ?? (Can't find it right now.)

 

[DaveEV]

IIRC someone reported L1 re-charge estimates as high as 25:00 ?? (Can't find it right now.)

surfingslovak's reverse SOC meter chart

FWIW - last time I went to VLBW 2 months ago, my car showed 22:00 to 100%.

 

[surfingslovak]

Great discussion, and very interesting data. Thank you, LEAFer. It's good to see Gerry's data as well. It's surprising to hear that he is seeing more than 20 kWh power draw from the wall after losing two capacity bars.

When I saw LEAFer's post initially, I thought that he might have between 230 to 240 Gids on a full charge. This would be based on the 120V charging display alone, assuming that it does not have an offset and was properly calibrated. The wall energy is similar to what TickTock saw on May 31, shortly after he lost his first capacity bar.

I thought that LEAFer would lose the first capacity bar relatively soon based on this data, but Gerry's post made me reconsider. It will be interesting to hear what will happen to his Leaf over the next few months.

My charge from turtle to 100% after the September 15th range test took 20.43 kWh after driving 71.8 miles.

My charge from shutdown to 100% on October 10th after driving 72.2 miles in D mode (21.8 miles total after LBW including 9.0 miles after VLBW) and then running climate control in the driveway to get turtle and then shutdown took 20.12 kWh.

Gerry, can you confirm that preconditioning was not used? Any idea what your recent Gid count might be? From the range test perhaps?

 

[DaveinOlyWA]

when the LEAF is new it has about 21 and a half kilowatt hours. so charging on l2 it 89 or 90 percent efficiency means it will take about 24 kilowatt hours

Your numbers don't add up. Heck - look at the first post of this thread - many reports of significantly higher turtle to 100% readings. Even surfingslovak recorded 24.5 kWh from the same type of Coulomb L2, after 6 months of ownership.

24 kWh * 90% = 21.6 kWh - at 4.5 mi/kWh one would get 97.2 miles before dead.

LEAFer got 20.544 kWh from the wall from turtle to 100%, which at 90% would indicate 18.5 kWh usable.

20.544 / 24 = 85.6% or 14.4% less than new (not 13% and assuming 24 kWh from the wall is new, when it really is 25-26 kWh).

LEAFer got 70.2 mi from 100% to VLBW at 4.5 mi/kWh indicating 15.6 kWh used. Do you really think he had 2.9 kWh remaining in his pack before it went dead? That would be another 13 miles at 4.5 mi/kWh between VLBW to turtle which is unheard of. In reality at 4.5 mi/kWh, there's no more than 6 miles left which would put total miles at 76.2 miles.

76.2 mi / 97.2 mi = 78% range of new. If he had 13% loss he should be able to do 84 miles at 4.5 mi/kWh.

Sorry, I have no idea how you're coming up with range loss ~13% when both my previous calculations match up nearly perfectly.

ya, saw those posts and they confuse me. putting 26 Kwh into a pack that is supposed to give up no more than 21.5 kwh is looking at just over 80% charging efficiency and i do better than that on my lowly modified EVSE running at 12 amps.

but there they are. all i can say is Phil'e EVSE upgrade is looking better and better every day

Here are my charging measurements on the Leaf:

Charging using the original 120v EVSE: (112.5v recorded at EVSE input)

Standby Power: 4.9w
Charge Power in: 1.451kW
Power to Leaf Battery: 1.125kW
Total Power Lost: 326w
Total Charge Efficiency: 77.5%

These measurements are all using our Rev2 Upgraded EVSE:

120v: (112.6v recorded at EVSE input)
Standby Power: 1.7w
Charge Power in: 1.436kW
Power to Leaf Battery: 1.125kW
Total Power Lost: 311w
Total Charge Efficiency: 78.3%

240v: (239.8v recorded at EVSE input)
Standby Power: 3.4w
Charge Power in: 3.756kW
Power to Leaf Battery: 3.414kW
Total Power Lost: 342w
Total Charge Efficiency: 90.9%

**edit** ok, just re read thread the quote http://www.mynissanleaf.com/v...onclick="window.open(this.href);return false; came from and Phil does state that losses INSIDE the battery are not considered which would be heat so then i guess 81% could be conceivable

this encouraged me to look back thru my charging records. i have only hit more than 23 Kwh twice and that was when charging at 120 volt with efficiency around 75%. there are 6 times i was in the 22's including twice on 240 volt 12 amp modified EVSE. 12 more at 20-22 kwh

so does 7-9% loss in heat sound valid? is there other internal battery losses to consider?

 

[TonyWilliams]

My charge from turtle to 100% after the September 15th range test took 20.43 kWh after driving 71.8 miles.

My charge from shutdown to 100% on October 10th after driving 72.2 miles in D mode (21.8 miles total after LBW including 9.0 miles after VLBW) and then running climate control in the driveway to get turtle and then shutdown took 20.12 kWh.

Gerry, can you confirm that preconditioning was not used? Any idea what your recent Gid count might be? From the range test perhaps?

Gerry, what was the miles/kWh for the 72.2 mile drive?

From Sept 15, 2012 - Silver679:

Start: 7:09am
Voltage: 393
Gid % : 74% (208)
Cap bars: 10 of 12
GOM : 75

*************

End: 8:24am
Miles: 71.8
Miles/kWh: 4.2
Voltage: 303.5
Gid: 1.4%(4)
Odd stuff: 18.3 miles after LBW (Black782 went 13.4 miles)

**************

Refill: 20.43kWh from L2 ?


20.43 * 85% charger efficiency = 17.3655 = 82.7% of 21 kWh

17.3655 * 4.0 = 69.42 miles (drove 71.8 miles)

 

[RegGuheert]

**edit** ok, just re read thread the quote http://www.mynissanleaf.com/v...onclick="window.open(this.href);return false; came from and Phil does state that losses INSIDE the battery are not considered which would be heat so then i guess 81% could be conceivable

In addition to that, Phil's measurements are *power* efficiency, not energy efficiency, which is what we are discussing in this thread. Specifically, Phil's numbers are power efficiency measured at 60% SOC. Energy efficiency over the full charge will almost certainly be lower than power efficiency at 60% SOC.

I suggest that we use the NREL LEAF Teardown and Detailed Test Results as the best values available to calculate recharge energy efficiency:

Energy from the wall from dead to 100%: 25.414 kWh
Energy from the onboard charger to battery: 22.031 kWh
Energy from the battery during discharge: 21.381 kWh

I will assume these tests were done using an L2 charger at 16A. From these numbers, we get the following energy efficiencies:

- L2 charging energy efficiency, wall to usable, unknown driving conditions, Dead(?) to 100%: 84.1%
- L2 charging energy efficiency, wall into battery, Dead(?) to 100%: 86.7%
- Battery energy efficiency, 100% to Dead(?), unknown driving conditions: 97%

The 84.1% number is the efficiency which is most pertinent for this thread, since we are trying to estimate usable energy available from a 100% recharge.

Based on that efficiency, I would say that LEAFer's battery has about the following usable energy:

20.722 kWh * 0.841 = 17.44 kWh usable

So the question remains: what do we compare this to for degradation estimation? The NREL number seems reasonable, but we do not know where they stopped their discharges. Using that we get the following degradation number:

20.722 kWh / 25.414 kwh = 81.5% of original LEAF capacity

So I, too, am wondering why LEAFer has not yet lost a bar, but I guess that is something to discuss in another thread.

 

[LEAFer]

20.722 kWh / 25.414 kwh = 81.5% of original LEAF capacity

So I, too, am wondering why LEAFer has not yet lost a bar, but I guess that is something to discuss in another thread.

If we don't lose that 12th bar soon I'll do another Turtle-100% test before we let the dealer touch it. (They've been sending cards about the P1273 recall, and the 2nd-year service is in mid-January, although we might hit 30k miles a little before that.)

 

[DaveinOlyWA]

I suggest that we use the NREL LEAF Teardown and Detailed Test Results as the best values available to calculate recharge energy efficiency:

Energy from the wall from dead to 100%: 25.414 kWh

http://www.mynissanleaf.com/viewtopic.php?p=152316#p152316" onclick="window.open(this.href);return false;

so we use the chart then factor in the "3rd party vendor" penalty?

 

[surfingslovak]

I suggest that we use the NREL LEAF Teardown and Detailed Test Results as the best values available to calculate recharge energy efficiency:

Energy from the wall from dead to 100%: 25.414 kWh

http://www.mynissanleaf.com/viewtopic.php?p=152316#p152316" onclick="window.open(this.href);return false;

so we use the chart then factor in the "3rd party vendor" penalty?

TomT's numbers were always an outlier. I monitored the energy economy and trip records he posted, most notably the 100-mile club entry, and all of them were out of the norm.

AFAIK the EPA measured about 24.5 kWh from the wall, which determined the MPGe ratings. Several of us used 85% charging efficiency, which includes battery losses (mainly heat) all this time. I don't really see a reason to change that in the light of the NREL report. If anything, it validates the work done previously.

 

[DaveinOlyWA]

TomT's numbers were always an outlier. I monitored the energy economy and trip records he posted, most notably the 100-mile club entry, and all of them were out of the norm.

AFAIK the EPA measured about 24.5 kWh from the wall, which determined the MPGe ratings. Several of us used 85% charging efficiency, which includes battery losses (mainly heat) all this time. I don't really see a reason to change that in the light of the NREL report. If anything, it validates the work done previously.

well 83.5 to 85% is the efficiency i am seeing from my modfied EVSE. thought faster charging would mean higher efficiency but looking like my efficiency is off due to not considering heat when discharging but that only affects the 80 watts/GID thing and this makes sense.

in my 100 mile trips, after posting stats it was always "you could have gone X more miles" when i found that hard to swallow. before i had the GID meter, it was easy to think that. now that i have the meter, i realize that i probably couldnt go that much farther due to these unconsidered losses.

 

[RegGuheert]

I found that the charging current is steady until it tapers during the last few minutes (on my car which is always charged to 100%).

The Leaf's OBC usually begins to start tapering at around 80% true SoC. For a full charge, It does not function as Gerry states, it definitely tapers down. But for an 80% charge it will behave as he indicated.

I cannot speak to what our LEAF does on L2 since we are not instrumented for that, but I will say that at L1, tapering does not start anywhere near 80%. Right now it has been on 12 bars for over one hour and is reporting 10 minutes remaining in the charge cycle (and has been reporting that for over 20 minutes) and the charger is still drawing the 1580W from the wall it has drawn during the entire charge. It is possible that the shunts are now active and some of the power is being dissipated rather than going into the battery, but I cannot see that.

 

[Ingineer]

The LBC (Battery Controller) stipulates the maximum charge current, (MCC) and it starts about 50kW and tapers depending on SoC, pack temperature, balance, etc. Once this number goes below the charging output, it will begin to taper. In most conditions, I usually see it begin to take a little off at not much over 80%. That's when charging full level 2 at ~3.4kW in. If you are charging level 1, that's only ~1.1kW, so it won't taper for quite some time later as the MCC crosses it's max level.

On my car, it almost always charges to 80% at 6.7kW in before it tapers.

-Phil

 

[RegGuheert]

Recharging from VLBW to 100%
Wall energy, L1, VLBW - 100%: 27.17 kWh
Time, L1, VLBW - 100%: 14.75 hours

I can only estimate L2 equivalent energy, but my estimate is certainly fraught with errors. To do this, I will assume L2 charging would have finished in 1/3 the time, or about 5 hours. During the additional 10 hours, I estimate 300W of power consumption by the LEAF for pumps, etc., for a total extra waste of about 3kWh. That gives:

Wall energy, L2 estimated: VLBW - 100%: ~24 kWh

I did another recharge today from VLBW to 100% using L1. Ambient temperature was about 70F at the end of the charge. Here are the numbers:

Recharging from VLBW to 100%
Wall energy, L1, VLBW - 100%: 25.83 kWh
Time, L1, VLBW - 100%: 16.5 hours

I can only estimate L2 equivalent energy, but my estimate is certainly fraught with errors. To do this, I will assume L2 charging would have finished in 1/3 the time, or about 5.5 hours. During the additional 11 hours, I estimate 300W of power consumption by the LEAF for pumps, etc., for a total extra waste of about 3.3kWh. That gives:

Wall energy, L2 estimated: VLBW - 100%: ~22.5 kWh

I must say I am having difficulty understanding this measurement compared with the July result. Specifically, how can I understand the July recharge consuming 2 kWh more energy while today's recharge lasted nearly two hours longer? I observed no tapering in wall power today less than 5 minutes before charging terminated. The only thing I can think of is that I recorded the total charge time incorrectly in July.

ETA: Odometer reading for this charge: 5668 miles

 

[RegGuheert]

The LBC (Battery Controller) stipulates the maximum charge current, (MCC) and it starts about 50kW and tapers depending on SoC, pack temperature, balance, etc. Once this number goes below the charging output, it will begin to taper. In most conditions, I usually see it begin to take a little off at not much over 80%. That's when charging full level 2 at ~3.4kW in. If you are charging level 1, that's only ~1.1kW, so it won't taper for quite some time later as the MCC crosses it's max level.

On my car, it almost always charges to 80% at 6.7kW in before it tapers.

Thanks for the details, Phil! This helps explain why you do not see much difference in temperature rise when charging at 3.3kW versus 6.6kW.

 

[camasleaf]

Just finished charging turtle to 100% on my new Leaf now at 430 miles. The Blink reported 24.9 kWh in 6.44 hours. I will try to turtle the older Leaf tomorrow.

 

[TickTock]

Just finished charging turtle to 100% on my new Leaf now at 430 miles. The Blink reported 24.9 kWh in 6.44 hours. I will try to turtle the older Leaf tomorrow.

Thanks, you've been added to the spreadsheet. When did you take delivery?

 

[Stoaty]

Just finished charging turtle to 100% on my new Leaf now at 430 miles. The Blink reported 24.9 kWh in 6.44 hours. I will try to turtle the older Leaf tomorrow.

Thanks, you've been added to the spreadsheet. When did you take delivery?

How about adding a column that shows percentage of a new Leaf (new Leaf from the NREL study = 25.414 kwh from the wall)?