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evnow
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Re: What SOC% does each bar on Leaf dash represent ?

Sun May 08, 2011 7:24 pm

MrFish wrote:As a follow-up, I recharged with L1 and a Killawatt meter. It required 27.65 kw AC to charge to 100% from dead, so it is safe to say that there was at least 24kw available from the battery pack, even with a 88% charging efficiency.

Looking at this 27.65 kwh, I think L1 may be less efficient than L2. Even EPA got lower number than that (about 25 kwh).
1st Leaf : 2/28/2011 to 5/6/2013
2nd Leaf : 5/4/2013 to 3/21/2017
Volt : 3/25/2017 to 5/25/2018
Model 3 : 5/10/2018 to ?

derkraut
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Re: What SOC% does each bar on Leaf dash represent ?

Sun May 08, 2011 8:44 pm

MrFish wrote:As a follow-up, I recharged with L1 and a Killawatt meter. It required 27.65 kw AC to charge to 100% from dead, so it is safe to say that there was at least 24kw available from the battery pack, even with a 88% charging efficiency.


Very informative/useful posts MRFish. Sort of helps take the guesswork out of some of the range issues. :) Thanks for sharing with us.
Derkraut
Color: Cayenne SLE, ETEC trim
reserved: 5/15/2010
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MrFish
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Re: What SOC% does each bar on Leaf dash represent ?

Mon May 09, 2011 6:42 pm

Very informative/useful posts MRFish. Sort of helps take the guesswork out of some of the range issues. :) Thanks for sharing with us.


Thanks, I've gained a lot from the site and know that it is good to give back a little.
The information that I shared helps me to be less of a conspiracy believer when it comes to Nissan and the battery.

Also, with my education being in healthcare (although I do have a AS degree in solar technology from the 80's) I didn't really have a very good understanding of Lithium batteries, so I found a easy to understand web article on understanding how difficult it is to measure available energy in a Li battery pack or SOC so I will share it for any other novices.

http://www.mpoweruk.com/soc.htm

I guess I will cut Nissan some slack.
"No American soldier has ever served on foreign soil to bring electricity to this country"

Miles= 41,000 in 26 months, 11 bars.............

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hill
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Re: What SOC% does each bar on Leaf dash represent ?

Wed Jul 06, 2011 6:20 pm

evnow wrote: Definitely they have remapped the bars. You got 10 miles on the 2 red bars (instead of 7 in others) and ten more after that. Is this all ath about the same speed ? ..................snip
Mine was at the same speed. Today I used 5 bars from a 100% charge, and still fluctuated between 78 and 82 miles projected range (ok I DO practice driving on the 'thrifty' side :D ) remaining, by the time I took this pic. From prior/similar remaining charge states, I estimate I'd go another 60-70 miles before power reduction mode. I'm REALLY hoping I'll get a chance to (purposefully) burn through an entire 100% charge. Still, as you alude, it all turns on whether one starts gunning it, using AC, maintaining high vs low speed, driving up grades, etc.

Image

I'm finding that we have about a 10% combined efficiency loss ( off the 5.5 mile/kWh car reading) from our 240V charging and DC-AC solar inverters ... which would leave us with just a tad under 5miles/kWh ... and at least 10 miles per bar average, when driving level ground, off freeway, no climate control.
.

Cinnabar
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Re: What SOC% does each bar on Leaf dash represent ?

Wed Jul 13, 2011 12:51 pm

MrFish wrote:
Summary:
2 red bars with 23 miles left on range meter.
0 red bars at 21 miles traveled (last 2 bars 10.5 miles average each)
8 miles traveled with 0 bars left before "turtle"
0.5 miles on turtle before stopped dead.
Total 30.2 miles traveled on 2 red bars at 4.0 kw/mile.

There seems to be a significant (~10%) cushion in range from the last 2 SOC bars to battery cut off.


Another thank you to this forum and its members. I forgot to plug in last night and was starting at 4 bars and a 32 mile commute this morning. If I hadn't read this previously, I might have waited to charge for a bit and gone into work late. However, being an informed MNL participant, off I went. Driving in ECO mode and staying mostly out of the HOV lane and going with the flow of traffic around 50 mph, I got to the office with one bar remaining and an estimate range left of 13 mi.

Also, thanks to my work place for having installed two ChargePoint L2 chargers.

kballs
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Re: What SOC% does each bar on Leaf dash represent ?

Mon Aug 01, 2011 4:33 pm

Cinnabar wrote:
MrFish wrote:
Summary:
2 red bars with 23 miles left on range meter.
0 red bars at 21 miles traveled (last 2 bars 10.5 miles average each)
8 miles traveled with 0 bars left before "turtle"
0.5 miles on turtle before stopped dead.
Total 30.2 miles traveled on 2 red bars at 4.0 kw/mile.

There seems to be a significant (~10%) cushion in range from the last 2 SOC bars to battery cut off.


Another thank you to this forum and its members. I forgot to plug in last night and was starting at 4 bars and a 32 mile commute this morning. If I hadn't read this previously, I might have waited to charge for a bit and gone into work late. However, being an informed MNL participant, off I went. Driving in ECO mode and staying mostly out of the HOV lane and going with the flow of traffic around 50 mph, I got to the office with one bar remaining and an estimate range left of 13 m



Based on my average miles/kWh for several recent trips that left 1-2 bars and the kWh taken to charge back to 100%, there are about 6-8 kWh left in the battery at the last 2 bars (22-30 miles at 3.8 miles/kWh). This corresponds very closely with your experience. This non-linear drain makes me nervous but I'm sure it reduces "I got stranded" news stories and articles. The problem is you think the car only has a 65 mile range unless you're brave enough to push it. Of course that last 20 miles could suddenly turn into 5 if you go 75mph uphill.

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planet4ever
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Re: What SOC% does each bar on Leaf dash represent ?

Tue Aug 02, 2011 1:22 am

I agree in general, kballs, except for your reference to "non-linear". I keep adjusting my rule of thumb a bit this way and that, but at present I'm assuming a linear 7½% per bar with an extra 10% after the last bar is gone before you hit turtle. (I consider anything you get in turtle as an emergency reserve, and not part of the normal capacity.) Using my numbers, you still have 25% when you drop to two bars. There is still some debate as to whether the usable capacity is 21 kWh or 24 kWh or something between, but 25% of those values would be 5 to 6 kWh. That puts me on the low side of your 6 to 8 kWh estimate.

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

kballs
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Re: What SOC% does each bar on Leaf dash represent ?

Tue Aug 02, 2011 7:27 pm

planet4ever wrote:I agree in general, kballs, except for your reference to "non-linear". I keep adjusting my rule of thumb a bit this way and that, but at present I'm assuming a linear 7½% per bar with an extra 10% after the last bar is gone before you hit turtle. (I consider anything you get in turtle as an emergency reserve, and not part of the normal capacity.) Using my numbers, you still have 25% when you drop to two bars. There is still some debate as to whether the usable capacity is 21 kWh or 24 kWh or something between, but 25% of those values would be 5 to 6 kWh. That puts me on the low side of your 6 to 8 kWh estimate.

Ray


You may be right about the linearness of the bars, I haven't drained through the last 2 bars enough to see how many miles I get for each, but it feels non-linear when there is still 25-35% of the battery left with only 16% of the bars left (hidden range with zero bars will definitely explain that). The other night I put 8 miles on the 2nd to last bar before plugging in and it was still lit, and the car took around 17.4kWh from the wall (dash average 3.9m/kWh at 63.3 miles is about 16.2 kWh), so subtracting charging losses it's about 6-8kWh left assuming 22-24kWh in the battery. Some might debate Nissan artificially limits usable kWh but they've said they let you use all of it (why have turtle mode at 21kWh used when you still have 12% left?). The only other thing that could limit usable kWh is a worn battery or low temperatures.

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planet4ever
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Re: What SOC% does each bar on Leaf dash represent ?

Wed Aug 03, 2011 4:23 am

kballs wrote:Some might debate Nissan artificially limits usable kWh but they've said they let you use all of it.

Really? Can you provide a citation for that? I'm not a battery expert, but I believe that the guys who are experts say draining a lithium battery to zero will pretty much destroy it, and charging it to the maximum possible will shorten its life in a major way. Nissan would be crazy to let you do either of those, given the battery warranty they provide. Toyota only lets the Prius use half its battery capacity. GM started with that goal for the Volt, but increased it (if I recall) to 65%. Nissan apparently lets us use somewhere between 80% and 90% of the battery, which is pretty gutsy. They apparently have a lot of faith in both their battery chemistry and their Battery Management System.

Nissan says we have a 24 kWh battery. Apart from a few wild-eyed optimists, the only real debate is whether they mean we have 24 kWh usable out of 27-30 kWh total, or 20-22 kWh usable out of 24 kWh total. Most, though not all, of the numbers seem to support the latter.

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

kballs
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Re: What SOC% does each bar on Leaf dash represent ?

Wed Aug 03, 2011 9:46 am

planet4ever wrote:
kballs wrote:Some might debate Nissan artificially limits usable kWh but they've said they let you use all of it.

Really? Can you provide a citation for that? I'm not a battery expert, but I believe that the guys who are experts say draining a lithium battery to zero will pretty much destroy it, and charging it to the maximum possible will shorten its life in a major way. Nissan would be crazy to let you do either of those, given the battery warranty they provide. Toyota only lets the Prius use half its battery capacity. GM started with that goal for the Volt, but increased it (if I recall) to 65%. Nissan apparently lets us use somewhere between 80% and 90% of the battery, which is pretty gutsy. They apparently have a lot of faith in both their battery chemistry and their Battery Management System.

Nissan says we have a 24 kWh battery. Apart from a few wild-eyed optimists, the only real debate is whether they mean we have 24 kWh usable out of 27-30 kWh total, or 20-22 kWh usable out of 24 kWh total. Most, though not all, of the numbers seem to support the latter.

Ray


Exactly, you debate it. I'm not saying you're absolutely wrong, but there are multiple pieces of evidence (anecdotal and factual) that lead me to believe usable capacity is 24kWh.

  • I don't have a citation, I just remember reading months ago a comparison of the Volt vs Leaf and how the Volt limits you to 10kWh but the Leaf lets you use the full 24kWh (but probably that the actual max was a little higher and unpublished).
  • Just like with a laptop battery, they have a published kWh capacity that you can take to 0 (which is not the same as 0 volts), and this is below the absolute max ratings of the cells (since charging/discharging to the maximums will kill it fast).
  • Why does Nissan give us an 80% charging option if they are already limiting usable capacity for maximum life? Granted they already have some safety buffer there but that's so you don't kill the pack in 10 cycles.
  • MrFish's experience shows 30 miles/4.0 miles/kWh = 7.5kWh which is within my 6-8kWh estimate. Are you saying that MrFish actually got 5-6 miles/kWh (30 miles/your estimate of 5-6kWh remaining) and that the 4.0 miles/kWh from his dashboard is bogus?
  • Based on people using 26-27kWh to charge from empty/turtle, I believe charging efficiency is closer to 90% than 75%.
  • The allowable voltage range from the Leaf's computer match AESC's published numbers, which also match up to 24kWh capacity. http://www.mynissanleaf.com/viewtopic.php?f=9&t=3498 I trust AndyH's assessment since he's an engineer that works with lithium batteries.

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