I want my 281!

[GregH]

Apparently the LEAF "equalizes" by bleeding off charge from
the higher-voltage cells. Then, the cells are closer to being "even".

If we could get a recording of one of those mystery charge blips every 45min (??) while balancing, we could calculate how fast the balancing can go. Say it was 45min then 1min of 4.5A charge, that would mean 100mA balancing. I'm guessing since all those bleeder resistors are inside the sealed battery pack, it's not very fast so as not to generate too much heat. Most of the systems I've worked with can only do about 100-200mA.

 

[garygid]

We believe that the BARS are NOT re-scaled for each 100% charge.

The manual seems to say that the BARS ARE re-scaled to 100% for Capacity-Loss.

We do not know if the "SOC" value gradually decreases with Capacity Loss.

Of course, that makes the fuel-Bars almost worthless, because they would
contain a variable (gradually or abruptly changing) amount of energy,
lower as Capacity Loss increases (Capacity decreases).

 

[mwalsh]

Of course, that makes the fuel-Bars almost worthless, because they would
contain a variable (gradually or abruptly changing) amount of energy,
lower as Capacity Loss increases (Capacity decreases).

Well thank heavens for the SOC meter then!

 

[garygid]

To make our SOC-Meter more useful, we still need to:
1. identify the "Capacity" value in the EV-CAN data
2. determine how the "SOC" value changes as Capacity decreases.

 

[TomT]

Assuming that SOC does not rescale too. We really don't know one way or the other at this point...

Well thank heavens for the SOC meter then!

 

[GregH]

We believe that the BARS are NOT re-scaled for each 100% charge.

The manual seems to say that the BARS ARE re-scaled to 100% for Capacity-Loss.

I'm not certain there is any difference... My "capacity" on any given day seems to be whatever my car charges to at 100%. I'd be willing to bet the transition points for "bars" in terms of SOC# scales to whatever the # was on that day's charge.. In other words, I'd bet the # at 80%, at 100% and at the loss of each "bar" all scale together. Is there evidence this is not the case?

 

[TonyWilliams]

I'm not certain there is any difference... My "capacity" on any given day seems to be whatever my car charges to at 100%. I'd be willing to bet the transition points for "bars" in terms of SOC# scales to whatever the # was on that day's charge.. In other words, I'd bet the # at 80%, at 100% and at the loss of each "bar" all scale together. Is there evidence this is not the case?

I think our 281 SOC number are the available capacity. There is too much evidence suggesting soft numbers for each fuel bar.

I predict that when there is that first capacity bar gone, we will know from the SOC numbers at 100%.

 

[GregH]

That was my point.. Soft numbers for the fuel bars but also soft numbers for the SOC# at 100%. I suspect they are related. And yes someday someone will sadly power up to a 100% charge only to find 12 fuel bars, 11 capacity bars, an SOC# in the 240s and that 12th fuel bar will go away around the 220s... Or do we suspect that on that day there will be 11 fuel and 11 capacity bars?

 

[garygid]

We think (from the Service Manual) that there will be 11 Capacity Bars, but still 12 Fuel Bars after a "100 percent" charge.

Like Capacity is tank size (that shrinks, but FUEL bars are 12 at 100% full. If the tank shrinks to 50% (6 bars), this smaller tank can still be "100% full" (12 fuel bars).

We suspect that smaller tank, when full, will still be at 281 raw SOC, but maybe not.

 

[TonyWilliams]

We suspect that smaller tank, when full, will still be at 281 raw SOC, but maybe not.

The $64 question.

 

[mwalsh]

90.3% / 254 for me last night.

This will tickle you guys..... So I charged my car to 100% on Thursday night, just to be sure it would be fully available to me on Friday, should I needed it. But all I actually ended up doing on Friday was moving the car into the street and back into the driveway, to avoid having the yard sprinklers get it. So imagine my surprise yesterday morning, when I went to drive down to HB and my indicated SOC was 92.4%. :shock:

 

[91040]

90.3% / 254 for me last night.

This will tickle you guys..... So I charged my car to 100% on Thursday night, just to be sure it would be fully available to me on Friday, should I needed it. But all I actually ended up doing on Friday was moving the car into the street and back into the driveway, to avoid having the yard sprinklers get it. So imagine my surprise yesterday morning, when I went to drive down to HB and my indicated SOC was 92.4%. :shock:

I noticed the same behavior yesterday. Started the car and noted that the meter read 80.1% for the 80% charge. A moment later, while driving down the driveway, it was reading 80.7%. Will be alert to this in the future.

 

[lincomatic]

It's been a lot cooler the past week, and the evenings are in the 60's. My car charges starting from midnight, and it's parked outside. On Friday night, it charged to 273#, vs 270# last week, when the days were hot and the nights warmer. It seems to me that ambient temperature isn't the main factor in the lower numbers.

 

[Boomer23]

It's been a lot cooler the past week, and the evenings are in the 60's. My car charges starting from midnight, and it's parked outside. On Friday night, it charged to 273#, vs 270# last week, when the days were hot and the nights warmer. It seems to me that ambient temperature isn't the main factor in the lower numbers.

Mine was a full 281 this morning after charging from 2 bars the night before. Another vote for ambient temp from me.

 

[LEAFfan]

I don't have a gauge yet, but I noticed the last two-three charges it only went to 9 bars/75% so I charged to 100% (for cell balancing) and now it charges to 10 bars/83% again (last two times). The garage has been in the 90's most of the time (after our string of 110+) the last few weeks.

 

[garygid]

Charging to 80%, finishing at "80% plus" shows 10 Bars, but "80% minus" shows only 9 bars.

However there is usually only a very small difference in stored energy (about 0.5%) between the two, NOT one full bar (about 7%).

 

[GregH]

My car seems to recalc the available capacity (SOC#) just about every time I power up the car if not more so.. Often when I park for a short while I'll come back and the # will be down 1 pt... But sometimes it can be up or down several points. I've seen it go down during regen events and at the end of charging... This would be a good job for can-do, I bet there are many instances where the number goes down during regen or up during discharge, or changes when the car is powered down then back up again. Discontinuities would be easier to spot on a long data log...

And on an older topic, I bet if we checked the different users we'd find a correlation between the # @ 100%, @ 80%, and @ 12th fuel bar (or any) vanishing. I'm away from my Leaf for the next week but from memory most recently I've been seeing 271/272# at 100%, 223/224# at 80% and around 250# for the 12th bar vanishing.

 

[LEAFfan]

Charging to 80%, finishing at "80% plus" shows 10 Bars, but "80% minus" shows only 9 bars.
However there is usually only a very small difference in stored energy (about 0.5%) between the two, NOT one full bar (about 7%).

I know that, but that wasn't my point. I believe balancing the cells by charging to 100% has given me back that partial tenth bar which I hadn't had for almost a month.

 

[garygid]

Charging to 80% recently:

80.4% 226 387v
82.2% 231 388.0v
81.1% 228 384v
82.2% 231 388.0v 19 Sep 2011

 

[91040]

I needed the whole 281 but only got 268 (95.3%), with the battery at 393 volts, from a "full" charge.

Got Low Battery Warning at 17.4% on the meter as usual. 3.8 miles after Very Low Battery warning (going uphill at about 30mph), saw the Turtle (my first time) and managed about 0.8 level miles more before the end.

The SOC meter read 1%/3 with 296.5 volts in the battery when the car went into Neutral.

The wheels stopped turning at mile 102.9 after mostly freeway driving at a maximum of 55mph. Round trip elevation loss and gain of 1300 feet. The Dash showed 5 mile/kwh average.

Without the SOC meter, there would be no way to know that I started with less than a full charge as the car showed 12 charge bars. In retrospect, knowing this, I should have been even more conservative with my speed.

Very sorry I don't have more data points. The tow was very efficient and painless. A very good learning experience!