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Re: I want my 281!

Posted: Sun Sep 11, 2011 8:39 pm
by garygid
231 raw SOC would be 82.1%

It looks like the lower the temperature, the higher the SOC numbers (for 80% or 100% charging).

Re: I want my 281!

Posted: Sun Sep 11, 2011 8:45 pm
by evnow
garygid wrote:231 raw SOC would be 82.1%

It looks like the lower the temperature, the higher the SOC numbers (for 80% or 100% charging).
But I only get 276 (once 279) @ 100%.

Re: I want my 281!

Posted: Sun Sep 11, 2011 9:07 pm
by GregH
We should probably stick to the raw # wherever possible.. Only the car knows what 80% and 100% are. Assuming 281# is 100% is probably not very useful... For all we know someone might be getting 282# and as we've seen many are now getting as low as 271# at "100%". We also don't know what the car considers to be 0%. From my last full charge with 80% at 224# and 100% at 271# I'd calculate 0% to be around 36# which is probably around the point the guess-o-meter goes blank with the super low battery warning. I'm not sure we've ever seen the car functioning below 4# either so saying 0% is 0# also doesn't seem useful.

Re: I want my 281!

Posted: Sun Sep 11, 2011 9:28 pm
by garygid
LBW is 50# (or 49#), shy 18%
VLBW is 25# (or #24), shy 9%

Raw SOC * 100 / 281 = Percent SOC.

Percent SOC * 281 / 100 = raw SOC

Re: I want my 281!

Posted: Sun Sep 11, 2011 9:55 pm
by 91040
The question is whether this raw number is useful in determining the amount of charge we have available to use. It seems that the car does not use it in deciding when to stop charging. So what does it represent and from what is it derived? Is it consistent at the low end of charge or is it as inconsistent as the upper end?

Will tracking any data from the SOC meter help anyone with this?

Re: I want my 281!

Posted: Mon Sep 12, 2011 7:02 am
by garygid
I believe that there MUST be another measurement that is used to:
1. stop charging
2. stop power usage for driving

Most likely:
1. The cell-pair (of 96) with the HIGHEST voltage hits a Upper-Limit to Stop Charging.
2. The cell-pair with the LOWEST voltage hits a Lower-Limit to stop "driving" the car.

The exact limit values might vary with temperature.

Without these safeguards, the highest (lowest) cell-pair can get damaged by over-charging (over-discharging).

The "SOC" that we are presented with is derived from something, but we are not sure what. We do know that it:
1. "generally" represents the "fullness" of the Battery Pack,
2. that it can (occasionally) indicate more energy at the low end than is actually available,
3. it drops noticably faster at the top end than the energy consumed.

Getting a better warning or estimation of the remaining, usable low-end energy is non-trivial, but that is what (one of the things) we are seeking.

Another important parameter is the battery temperature, its rise as we drive and charge, and its fall as we let the LEAF "rest" and cool.

For example, does parking for 8 hours in the summer sun in AZ produce heating equivalent to the heating of 4 Quick-Charges?

Re: I want my 281!

Posted: Mon Sep 12, 2011 1:24 pm
by abasile
While I don't have any particularly unique information to share, I figure that it never hurts to add another data point or two. I had the use of an SOC meter for about 24 hours, having borrowed tbleakne's unit. Saturday night and Sunday morning, I charged to 100% using L1 with an average ambient temperature in the 60s. The reading within 15 minutes of charge completion was 276. On Sunday we drove about 40 miles (end SOC ~ 57%), then charged up to 100% at tbleakne's house on L2, with 70ish temps. The reading immediately following charge completion was 275. We've put on over 4500 miles in over 4.5 months of ownership.

Also, we had no trouble driving home to the mountains from tbleakne's house. After a total of ~50 miles and 4900 feet of net elevation gain, we ended up with one full bar of charge (and sadly, no SOC meter; I'll have to order a kit). Of course, that required gentle, efficient, somewhat slow driving on the 210 freeway and Highway 330.

Re: I want my 281!

Posted: Mon Sep 12, 2011 1:57 pm
by Stoaty
abasile wrote:Also, we had no trouble driving home to the mountains from tbleakne's house. After a total of ~50 miles and 4900 feet of net elevation gain, we ended up with one full bar of charge (and sadly, no SOC meter; I'll have to order a kit).
OT - I am thinking about buying a kit also. 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)?

Re: I want my 281!

Posted: Mon Sep 12, 2011 2:19 pm
by abasile
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.

Re: I want my 281!

Posted: Mon Sep 12, 2011 2:24 pm
by mwalsh
Differences last night.....cooler night and charging from over 50% SOC. So I'm going to put it down to pack temps (which is something I've suspected in the past):

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