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mwalsh
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Re: I want my 281!

Wed Sep 14, 2011 10:38 am

This morning - 92.8 / 261. Variables - starting from around 25% charged; battery warmer from car not sitting as long since last use; warmer night.
2011 Blue Ocean SL with 87,000 miles
2015 pack on 12/30/15
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LED shifter
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garygid
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Leaf Number: 000855
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Re: I want my 281!

Wed Sep 14, 2011 10:44 am

Also, starting from lower SOC, the battery gets hotter at the end of charging.

Here are some temp curves from a 6-hour charge L2 16A from about 10% to 100%
Image

Here are some temp curves from a drive
Image

So, might Blue be the Battery Pack?
See SOC/GID-Meter and CAN-Do Info
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Boomer23
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Re: I want my 281!

Wed Sep 14, 2011 12:15 pm

mwalsh wrote:This morning - 92.8 / 261. Variables - starting from around 25% charged; battery warmer from car not sitting as long since last use; warmer night.
Mine was 98.2/276 this morning. 100% charge starting from 2 bars and 26.3%

Since we're talking about starting SOC before charging, when I hit 100% and 281 the other day, I was starting from 6 bars and 58.3% SOC.
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mwalsh
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Joined: Thu Apr 22, 2010 10:10 am
Delivery Date: 05 Jan 2011
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Location: Garden Grove, CA

Re: I want my 281!

Wed Sep 14, 2011 12:20 pm

Boomer23 wrote:Mine was 98.2/276 this morning. 100% charge starting from 2 bars and 26.3%
What time yesterday did you last use your car? Mine would have gone to bed around 5pm.
2011 Blue Ocean SL with 87,000 miles
2015 pack on 12/30/15
Tinted windows
Bosch AGM 12v
Ecopia 422+ tires
L1 EVSE upgrade
FIAMM horns
Superbright LED lighting
2013 sun visors
LED shifter
Heated seats
GT-R map lamp lenses
Altima illuminated door switches

tbleakne
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Delivery Date: 03 Jun 2011
Leaf Number: 2400
Location: Claremont, CA

Re: I want my 281!

Wed Sep 14, 2011 2:27 pm

abasile wrote:
Stoaty wrote:What color was the LED on tbleakne's SOC meter. Did it look good with the car? Was it easy to read (even in sunlight)?
tbleakne's meter is black, with blue LEDs. It blends in well enough, and looks decent. However, it isn't as easy to read as I would prefer, particularly at an angle. Reading it in sunlight is difficult at best. However, at least for myself, I wouldn't consider that a showstopper.
The blue LED is actually quite bright, so much so it is hard to take a picture in which the blue is not over-exposed, but in diffuse daylight the unlit segments are distracting. I have it mounted low, so direct sunlight on the display is rare. Gary has found a plastic filter that suppresses the distractions for the red, and he plans to have a blue filter soon.

Here is my best photo. I have adjusted the exposure curve quite a bit, but still the picture shows less blue saturation than real life.
Image
LEAF Ocean Blue SL, "100 % Electric" decals, Delivered June 3, 2011
Sold June 2014 27K miles, 18% capacity loss, 1 bar, 5.0 mi/kWh.
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tbleakne
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Re: I want my 281!

Wed Sep 14, 2011 3:49 pm

garygid wrote:Any chance you three with meters (Mike, Boomer, Tony) >>>
I reported my first results with my SOC meter on Sept 7, so you can add me to this list.
Here is that post, in which I computed a preliminary regen efficiency value of 73%:
http://www.mynissanleaf.com/viewtopic.p ... 43#p129043

For the current topic, on Saturday, 9-10, charging to 100% at L2, starting at 1:30AM with no end-time limit, the charge stopped at 271. Car's temperature when I checked at 7 AM was 80 degrees. I re-started charge, and got it to 275.

On Sunday, 9-11, I charged to 11 bars on L2 and then switched to L1 to complete charge to 100%. Hill had suggested this strategy several months ago. It did not help - charge still stopped at 274/275.

Above 11 bars at L2 the SOC rev8 shows interesting short-term fluctuations in the charging power, as the car does its "best" to squeeze in that last bit of charge.

It may have been reported elsewhere, but here are my results on charging efficiency, using the rev8 display of power going directly into the battery (voltage*current):

L1 (12A) .95KW/1.4KW = 68%
L2: (16A) 3.3KW/3.8KW = 87%
Wall-power was measured with Kill-a-Watt for L1 and TED for L2. Until now we really didn't know how much got into the battery. There was early speculation that Nissan's specification of 3.3KW for L2 charging was low, but now we know they were truthful. Many of us believed that the charger efficiency would be 94+%, like modern solar inverters.

Note L1/L2 = .95/3.3 = 29%. L1 takes 3.5 times as long as L2.

While 87% at L2 is disappointingly low, this room for improvement suggests to me that a better-designed 6.6KW charger, operating at perhaps 94% efficiency, would dissipate the same amount of waste heat, and so it could run with the present cooling system.

Stats on my Leaf:
2800+ miles
Owned 15 weeks
Charged to 100%: perhaps 8 times (including 2 times this weekend to do these tests).
Charged to 11 bars: frequently, 3 or more times/week.
Charged to 80%: ~2 times/week
No overnight charge: ~1/week
Extra afternoon charge on weekends (off-peak TOU): 2-3 times/month
Except for extra-charge days, car has 4-6 hours to cool before charging starts.
I never charge to 100% on extra-charge days.

Conclusion: having a "newer" car and charging to 100% infrequently does not help reach a full 100%. My car likely gets hotter in its garage than most of the other cars reported here, although I would think recent freeway driving raises battery pack temperature more than ambient conditions.

I suspected long before I got the car that elevated temperatures could be a problem in my garage. I installed a new insulated garage door. When I am home I frequently open a rear door and the garage door part way to allow cross-ventilation. The new solar panels on my garage roof provide some shade, but in hot weather the garage still gets perhaps 10 degrees hotter than ambient, which has reached the high 90s a number of days this Summer. I plan to install a ventilation fan on a timer before next Summer.

When I was out of town for a week, I left my Leaf in its hot garage with 50% (6 bars) of charge. This is recommended for Li-cobalt batteries.
LEAF Ocean Blue SL, "100 % Electric" decals, Delivered June 3, 2011
Sold June 2014 27K miles, 18% capacity loss, 1 bar, 5.0 mi/kWh.
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surfingslovak
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Re: I want my 281!

Wed Sep 14, 2011 4:01 pm

tbleakne wrote:It may have been reported elsewhere, but here are my results on charging efficiency, using the rev8 display of power going directly into the battery (voltage*current):

L1 (12A) .95KW/1.4KW = 68%
L2: (16A) 3.3KW/3.8KW = 87%
Very interesting data set, thank you for that. I assumed that the L1 charger was delivering about 1.1 kWh every 60 minutes, but I rounded it down for the SF BayLEAFs presentation last Saturday. Conversely, I rounded L2 down to even 3 kWh every 60 minutes, but it appears that this number is a bit higher. Nice to see that the estimated average 85% L2 efficiency factor seems to hold up.
Last edited by surfingslovak on Wed Sep 14, 2011 4:25 pm, edited 1 time in total.

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planet4ever
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Leaf Number: 1537
Location: Morgan Hill, CA, south of San Jose

Re: I want my 281!

Wed Sep 14, 2011 4:14 pm

tbleakne wrote:L1 (12A) .95KW/1.4KW = 68%
L2: (16A) 3.3KW/3.8KW = 87%
<snip>
Note L1/L2 = .95/3.3 = 29%. L1 takes 3.5 times as long as L2.
Thank you for providing actual measured values, but if you don't mind, I'd like to see a confirming test. You call 87% disappointing, but it was about what I was expecting. 68%, on the other hand, I would call horrifying. Nissan has claimed that L1 takes 3 times as long as L2 (21 hours vs. 7 hours), not 3.5 times. Like surfingslovak, I've assumed something closer to 1.1kW at the battery for L1.

Ray
End of April 2013: Traded my 2011 SL for a 2013 S with charge pkg.

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Boomer23
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Delivery Date: 30 Mar 2011
Location: Orange County, CA

Re: I want my 281!

Wed Sep 14, 2011 5:35 pm

mwalsh wrote:
Boomer23 wrote:Mine was 98.2/276 this morning. 100% charge starting from 2 bars and 26.3%
What time yesterday did you last use your car? Mine would have gone to bed around 5pm.
Mine was last driven at about 9:45 pm for a quick grocery trip.
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tbleakne
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Re: I want my 281!

Wed Sep 14, 2011 5:40 pm

surfingslovak wrote:
The battery temperature gauge is very coarse, and if the fine folks from the Chevy Volt universe can be believed, the delta between 70°F (21°C) and 90°F (32°C) can be critical to battery life.
This looks Chevy Volt link very looks relevant to our temperature concerns because it says the Volt also uses Li-Mn batteries.
As Frank Weber and others have noted, there is a substantial lifetime difference between 21C (70F) and 32C (90F) in the lithium-manganese batteries (which have the highest heat sensitivity/degradation profile of all lithium battery chemistries) that GM is using in the Volt. At 60% SOC, lithium-manganese batteries have a little over 8 year life at 21C (70F) but only a 5 year life at 32C (90F). At higher states of charge, the heat sensitivity and degradation rate is even greater.
My understanding was that Li-Mn had less temperature sensitivity than Li-Co, and this was why the Leaf didn't need active thermal management, while the Tesla, using Li-Co, did. What have I missed ?
LEAF Ocean Blue SL, "100 % Electric" decals, Delivered June 3, 2011
Sold June 2014 27K miles, 18% capacity loss, 1 bar, 5.0 mi/kWh.
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