vrwl
Well-known member
toasty said:
how is this for a 2011 w 18k miles?
Pretty good considering I've got 88-89% on my 2011 with less than 7k total miles.
toasty said:
how is this for a 2011 w 18k miles?
Yes, I would enter 67.57 Ah instead of the default 66.2556 Ah as reference capacity in the preferences:klapauzius said:I got this after a 100% charge on the blink:
94.4% SOC
23.0 kWh
287 Gids (102%)
AHr=67.57
CAP=101.98%
on a 2 1/2 year old battery with 18k miles.
Too good to be true? Is there some initial calibration required?
Gids are simulated, but the SOC and CAP values come straight from the CAN bus. You need to set the reference capacity in the preferences to get more realistic kWh and Gid readings. We cannot be certain, but there is a chance that new LEAFs limit usable capacity to 281 Gids, even though the battery could have higher nominal capacity. There were several new LEAFs, which were well above 66.2556 Ah.klapauzius said:Where do the AH values and the SOC values come from? Are these computed values or do the come from the car itself?
What about the GIDs? Are the ones reported in this app the same as the GIDs from the GID-meter? Likely not, since a value of 287 seems unreal.....
lencap said:Is there a version of this app that runs on the iPhone? I can't find anything similar so far.
klapauzius said:I got this after a 100% charge on the blink:
94.4% SOC
23.0 kWh
287 Gids (102%)
AHr=67.57
CAP=101.98%
on a 2 1/2 year old battery with 18k miles.
Too good to be true? Is there some initial calibration required?
surfingslovak said:Gids are simulated, but the SOC and CAP values come straight from the CAN bus. You need to set the reference capacity in the preferences to get more realistic kWh and Gid readings. We cannot be certain, but there is a chance that new LEAFs limit usable capacity to 281 Gids, even though the battery could have higher nominal capacity. There were several new LEAFs, which were well above 66.2556 Ah.klapauzius said:Where do the AH values and the SOC values come from? Are these computed values or do the come from the car itself?
What about the GIDs? Are the ones reported in this app the same as the GIDs from the GID-meter? Likely not, since a value of 287 seems unreal.....
If that was the case, then the simulated GIDs and the"real" Gids should match?drees said:Ah readings appear to be directly related to GIDs.
It looks like I can keep the battery temperature to a max of 86 degrees as long as the ambient temperature for the day doesn't exceed 90 degrees and I park in the shade (based on test done today where max was 90 degrees). Last summer I wouldn't drive my Leaf to work if the high temperature was predicted to be 95 degrees or greater. I may have to consider lowering the threshold a bit.JPWhite said:Daily degradation appears to be .02 or .03 Ah. So once battery temp gets above 86 or so, the degradation accelerates by one order of magnitude !!
This is just one day, but it does look like single incidences can impact overall battery health.
LEAFfan said:JPWhite said:I noticed I had lost quite a bit of battery capacity in short order. I found it was Thursday (May 16th) and did an analysis of what was going on to cause the 0.3 reduction in Ah in a single day.
As one might predict based on what happened (and is happening) in Arizona, high battery temp is the culprit.
...
Battery Ah never recovered overnight after cooling.
Daily degradation appears to be .02 or .03 Ah. So once battery temp gets above 86 or so, the degradation accelerates by one order of magnitude !!
This is just one day, but it does look like single incidences can impact overall battery health.
Yep, a lot of research shows battery degradation begins at 87F. The App should stay yellow (up to 86F) until the BT reaches 87F.
...My capacity reports at app-reported temps from ~59 f to ~86 F are extremely consistent, varying only ~0.20 % since the first capacity report I got at the SF BayLEAFs meeting over a month ago. Most recently:
That being said, I think they are consistently wrong, in showing an ~12.5% loss of capacity, which has not shown up in my LEAF by either recharge or range capacity tests...
klapauzius said:Well, all I would care for is the AH value, so if it is indeed 67.57 Ah, that would be terrific.
So there were 2011 Leafs with higher than 66.2556 Ah? My understanding was that there werent GID readings higher than 281?
So how do GIDs and AH (apparently both from the CAN, albeit with different applications...the GID meter would read the CAN-GIDs, right?) reflect capacity then, if they are not the same?
The question is, is the AH reading a more accurate reflection of capacity than the CAN-GIDs? Or is it some fudged number that the car makes up from inaccurate and variable readings? You would think for coulomb counting the car would have to be discharged and charged completely?
GregH said:Ah/Coulomb counting doesn't work so great on the Leaf because the current sensor is only precise to 0.5A and only accurate +/- 1.5A.. makes it very difficult to count Ahs when charging at 3.3kW!
When my 2011 Leaf was ON, not moving I'd typically see about 1A draw. When my new 2012 Leaf is ON, not moving I typically see about 0A draw. I haven't seen any indication of self calibration in the BMS (you'd think it wouldn't be very hard.. just measure after the contactors open or before they close). Without calibration the difference of 1A over the course of a 5 hour charge at 8-9A can be rather large. We haven't found anything akin to a running Ah counter in the data so far.klapauzius said:GregH said:Ah/Coulomb counting doesn't work so great on the Leaf because the current sensor is only precise to 0.5A and only accurate +/- 1.5A.. makes it very difficult to count Ahs when charging at 3.3kW!
If you integrate a noisy random variable over time, the sum becomes much less random. If you integrate e.g. 8 Amps with an error of +/- 1.5 A every second, the result will still be very accurate, because the error grows only with sqrt(N), where N is the number of measurements.
If your unit of measure is AH and you measure current with a random error of +/- 1.5 A every second (lets assume it is Gaussian with a standard deviation of 1.5 A) , your error on the AH measure is just 0.025 AH or 1.5 *sqrt(3600) =90 As. So Coulomb counting will actually work very well.
Anyway, does anyone have an idea how the AH number is calculated?
Maybe this has been discussed elsewhere already?
klapauzius said:Anyway, does anyone have an idea how the AH number is calculated?
Maybe this has been discussed elsewhere already?
Since I've just invested in a black Leaf :shock: I'm actually somewhat pleased to report that the insulation between the battery and the passenger compartment works pretty well. I've come out to a baking car after an hour of direct sunlight and found the temperatures still calm.. mostly because it WAS in the shade and thus the pavement under the car was still cool. I actually notice slight cooling during the morning commute which tells me cooling the underside of the car is more important than cooling the passenger compartment. Kinda flies in the face of thermodynamics, but that's what I've seen so far. Yes, though, that would be an interesting test.lukati said:Now that we can read battery temperature accurately, an interesting experiment can be done. Park a black and a white car next to each other in a sunny lot and determine the battery temperature as a function of time. That would tell us whether it is a good idea to buy a light color Leaf in warm climates.
Makes me wonder if putting a small fan under the car at night to circulate air better would improve night time cooling during the summer months when I need it most. The air in my underground parking garage doesn't move much.GregH said:I actually notice slight cooling during the morning commute which tells me cooling the underside of the car is more important than cooling the passenger compartment. Kinda flies in the face of thermodynamics, but that's what I've seen so far.
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