Normal range from SOC bar 1 today?

I haven't seen what I'd consider the "proper" range from bar one on the SOC meter since the first week with my car. Instead, seemingly irrespective of how I drive, I've begun to expect no more than 3.5 miles from it. In fact, I now consider that "normal". So imagine my surprise today when I got 6 miles out of bar one!

What was different about today?

Well, there were several differences from my normal charging routine:

1) The car was already at ~80% charged when I went to fill manually yesterday afternoon. It took only a couple of hours to get to 100%.

2) I decided to leave the car plugged in last night, because I wanted to try cabin pre-conditioning this morning (knew it was going to be on the cold side). So (and this was an oversight on my part), the charge timer kicked in at some point and attempted to charge the already full battery. Now I don't know when this started but, because I have charging set based on end time, I got two charging completed messages - one at 10:09pm and one at 12:07am (this is normal abnormal behavior when you charge based on end time).

3) It was quite cold last night, and we've already talked about how cold weather enables a battery to store more. But I wouldn't say it was a whole lot colder than many of the previous nights I've charged.

4) Because I pre-conditioned the car this morning (the first time I've actually used the heater while plugged in), the EVSE was connected and pulsing charge into the battery pack, as it does. Those of you who have done this before will know is normal operation.

So would anyone care to speculate on why this apparent restoration of full range within this one bar has occurred?

It might have to do with cell balancing, which someone has stated only happens when fully charged.
http://www.mynissanleaf.com/viewtopic.php?f=27&t=2746

The balancing conversation was split out into a new thread.
http://www.mynissanleaf.com/viewtopic.php?f=9&t=2795&start=0

Have we determined yet how the display reacts when the car loses capacity? Does the loss come out of the top bar until you have no top bar, then the second to top bar, etc. or does the entire battery capacity get spread equally over all of the bars so that each bar represents a narrower range of charge?

LakeLeaf said:

Have we determined yet how the display reacts when the car loses capacity? Does the loss come out of the top bar until you have no top bar, then the second to top bar, etc. or does the entire battery capacity get spread equally over all of the bars so that each bar represents a narrower range of charge?

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My experience thus far would seem to indicate that you'd eventually loose bars.

mwalsh said:

My experience thus far would seem to indicate that you'd eventually loose bars.

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Thanks - I take it then that you might be thinking your quick first bar is a reflection of a little loss of capacity?

LakeLeaf said:

Thanks - I take it then that you might be thinking your quick first bar is a reflection of a little loss of capacity?

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Well, I did. But now that I seem to have inadvertently come up with a way to restore full capacity.......

mwalsh said:

My experience thus far would seem to indicate that you'd eventually loose bars.

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The user manual seems to say all 12 bars will be used - it will be a % of the total capacity.

evnow said:

mwalsh said:

My experience thus far would seem to indicate that you'd eventually loose bars.

Click to expand...

The user manual seems to say all 12 bars will be used - it will be a % of the total capacity.

Click to expand...

Certain aspects of the data on the CAN bus lead me to believe (but not prove) that the bars would always show 0-100% of whatever the total capacity is at that time. So if the capacity bar was at 50%, then the full scale (100%) SOC bargraph would be 50% of the original 24kwh.

BTW, more data for you.....full measure of 12th bar use again today! Actually 7.5 miles, because of some stop-and-go traffic (so 1.5 miles on city streets, 5 miles highway at 66mph, and another mile in stop-and-go).

So what happened?

Yesterday I had the guys from Nissan come visit, so I played safe and had the car charged to 100%. Well, it turned out we didn't drive all that far, but it was far enough to use bar 12. Since I don't currently have my portable EVSE (on loan to JPVLeaf), I decided I wanted the comfort of a full pack when leaving from home today and put the car on charge anyway, manually. It took about 40 minutes to full.

So what did I surmise from this? Well I'm of the opinion that you can cram more into the upper bit of the pack IF you allow the pack to charge and rest before topping off. What I may do to try and validate this theory is charge to 80% using the timer and then top-off from 80% manually. Trying this both well in advance of needing the car and immediately before needing it. This should either reinforce or refute the notion I have of pack bleed-off from 100% charging.

It appears that not all cars charge to the same level. Some charge to "281" some to "270". Yet everyone has a top bar. Either the graph is scaled, or the top bar covers a wider area on some cars than others.

I had the opposite experience to you, Mike. On Sunday, my wife and I went for a "country" drive to a winery to pick up our club shipments. Then we took freeway for about 15 miles coming home. Whereas I normally lose the first bar at 6 miles, on Monday I lost it at 4.5. And I used 5 bars to get to work instead of 4. Tuesday, first bar went at 5 miles and I was thinking I would call up my PD and ask for a battery check. By today, I was back up to >6 for the first bar, and average of 7 overall. I pretty much count on 7/bar. My commute is nearly identical to yours.

Oh yeah, I took the LEAF up to SF for our BayLEAFs gathering on June 4th. It was cold and rainy and I still got 7 mi/bar. Go figure.

I'm a full time D-mode driver now. Only use ECO when going through residential neighborhoods, where kids may spill out into the street. ECO is a good governor.

gascant said:

I had the opposite experience to you, Mike. On Sunday, my wife and I went for a "country" drive to a winery to pick up our club shipments. Then we took freeway for about 15 miles coming home. Whereas I normally lose the first bar at 6 miles, on Monday I lost it at 4.5. And I used 5 bars to get to work instead of 4. Tuesday, first bar went at 5 miles and I was thinking I would call up my PD and ask for a battery check. By today, I was back up to >6 for the first bar, and average of 7 overall. I pretty much count on 7/bar. My commute is nearly identical to yours.

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Hmmm.....I haven't seen a full measure of use (without the aforementioned trickery) out of that first bar since the second week of ownership. Perhaps there is something wrong with my pack!

Presumably, to protect the cells when charging to 100%, the highest voltage cell-pair must stop the charging when it gets to the "100% user-full" level. Otherwise, continuing to charge would "over-fill" that highest cell-pair and possibly damage it, or shorten its useful life.

At that time, all the remaining cell-pairs will be slightly to somewhat "not-quite-full", and the Battery Pack will be at a slightly to significantly lower total voltage.

This could explain why we have seen "271" to "281" in the EV-CAN data for our presumed "State of Charge" (SOC) value.

Then, since the bars appear to be related to SOC levels, some (with "271") would lose their first bar sooner that somebody that started with "281"?

Perhaps gathering more data will help. I suspect that being able to see all the cell-pair voltages after a 100% charge would be very useful.

evnow said:

mwalsh said:

My experience thus far would seem to indicate that you'd eventually loose bars.

Click to expand...

The user manual seems to say all 12 bars will be used - it will be a % of the total capacity.

Click to expand...

I'll have to do some research. I thought that the number of small bars on the right would recede as capacity is lost over the years. If it doesn't act that way, then why does it light up all the short bars on the right? It doesn't make sense that they would always be lit no matter what the capacity is....

from what I read in the manual capacity bars drop off as the battery degrades

so at some point you lose a bar

makes sense, its a capacity gauge
I wonder hown the guess o meter deals with the loss of battery capacity

hopefully it will be some time before we see the loss of the first bar

BTW how many bubbles does it take to keep the car at 60mph on level road?
65mph?

I'm interpreting from the owners manual and the illustration below that "small" bars will be lost on the right as battery capacity falls off...

It appears that one needs to lose something like 8.3% of the Battery Pack capacity before the top bar of the capacity gauge would not show.

It is not clear if the "fuel" gauge (bars) is showing the percent of present capacity (would be quite misleading and almost useless), or the percentage of the original capacity (which would be useful).

If the latter, a 100% charge will eventually be only "11-bars" worth of usable charge, not a "full" 12-bars worth of usable charge. If it continues to display 12 bars, then the usable "capacity" of each bar will be shrinking,

We shall see. Hopefully, the CAN-buss analysis will help us understand the car better.

garygid said:

It is not clear if the "fuel" gauge (bars) is showing the percent of present capacity (would be quite misleading and almost useless), or the percentage of the original capacity (which would be useful).

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User Manual says it will always show full 12 bars at 100% capacity (ofcourse, subject to firmware changes).

Nope, not have I. My experience mirrors yours (minus the trickery)...

mwalsh said:

Hmmm.....I haven't seen a full measure of use (without the aforementioned trickery) out of that first bar since the second week of ownership. Perhaps there is something wrong with my pack!

Click to expand...

mogur said:

Nope, not have I. My experience mirrors yours (minus the trickery)...

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Well, glad to hear that it's abnormally normal! :lol: