Real SOC (State of Charge) - Information

[garygid]

TickTock,
Glad they are making some discoveries,
and hopefully progress with your car.

I would have wanted to see the cell-pair voltages (AND cell-pair numbers) both near 100% and near "empty".

If the SAME cell-pair is HIGHEST when full and LOWEST when near empty, you have identified your low-capacity cell-pair.

[davewill]

... Got an update from the dealer earlier today. They have acknowledged that my range does seem to be lower then it should. ...

Very good news...not that your car is faulty, but that your dealer is taking you seriously and doing the diagnostic work needed to find the problem. This has been a worry of mine, that deficiencies like this were going to prove impossible to have fixed under warrranty because there's no way to truly verify them if the dealer refuses to do so.

[tbleakne]

How many volts do you have in the CV phase of charging to 100% and at what voltage your 80% charges terminate?

Mine are 394V for 100% and 388,5V for 80%, and after charging they drop to 393V and 385,5V.

Interestingly, my voltages are identical. For 80%, I get 387-391 and for 100% I get exactly 394 every time (no variation).

This is very consistent with my understanding, which is that the BMS stops the charge (to 100%) when the battery pack reaches a fixed voltage, which Nissan has set to 95% of the maximum the battery will safely handle. More precisely, if the cell-pairs are not well balanced, it will stop when the weakest cell-pair reaches this setting. A weaker cell-pair hits this voltage limit early, reaching its maximum capacity of coulombs before the other cell-pairs. The cell-pair may be temporarily weaker due to elevated temperature, or permanently weaker.

The 80 watt-hrs for a gid increment is determined by integrating the discharge current times a running estimate of the idle voltage. When the battery goes to idle this idle voltage estimate is corrected. The chief engineer at Google mentioned this. This is why the gid reading can change one or two counts after the car stops (or goes into neutral).

<Edit>
I was thinking that most of your battery impairment might be in just a few weaker battery modules that could be replaced without replacing the whole pack, but the fact that you are reading full pack voltage when the charge stops suggests that the pack is, in fact, well-balanced.

[dhanson865]

Got an update from the dealer earlier today. They have acknowledged that my range does seem to be lower then it should. They ran side by side test with their demo starting with 100% charge and after 39 miles, my car had 35 miles remaining on the GOM and theirs had 53. Sent logs to Osaka to analyze. So one more piece of evidence that gids really are a measure of available charge (just to show this really isn't off-topic ).

They had to drive two cars 39 miles in order to figure out there was a problem??? I would have thought their fancy equipment would tell them in a heartbeat if there was a problem with the battery.

Don't discount the value of empirical evidence. Even if the fancy equipment says something is wrong they may do empirical tests to see how the math translates to real world behavior.

If they are trying to decide on replacement policy for battery packs that exist in tens of thousands of cars and each pack cost thousands of dollars I think it's worth driving two cars 40 miles to get more data. Heck it's cheaper than driving two Sentra's that distance with labor costing them more than the electricity on the Leaf.

[cvad1]

Hello everyone,

I am a student researching on optimizing EV charging stations. For my research, I require the SOC and voltage data that comes out of the LeafSpy application in a .csv format for Nissan Leaf 2013 or higher versions. Could anyone please help me out with this?

Thanks
Chinmay
chinmay.9@gmail.com

[WetEV]

Hello everyone,

I am a student researching on optimizing EV charging stations. For my research, I require the SOC and voltage data that comes out of the LeafSpy application in a .csv format for Nissan Leaf 2013 or higher versions. Could anyone please help me out with this?

Thanks
Chinmay
chinmay.9@gmail.com

What university? Do you have an .edu email address?

What exact fields do you want? Just SOC and voltage? Charging or driving or both?

[cvad1]

Hello,

I'm a Masters Student at Arizona State University. You can reach me at cvad1@asu.edu.

I don't exactly know what the LeafSpy app outputs but a charging log and a trip log would be great. I am looking out for data which shows the variation of SOC when we start charging.

Thanks,
Chinmay

[WetEV]

Hello,

I'm a Masters Student at Arizona State University. You can reach me at cvad1@asu.edu.

I don't exactly know what the LeafSpy app outputs but a charging log and a trip log would be great. I am looking out for data which shows the variation of SOC when we start charging.

Thanks,
Chinmay

LeafSpy log has these fields:

Date/Time,Lat,Long,Elv,Speed,Gids,SOC,AHr,Pack Volts,Pack Amps,Max CP mV,Min CP mV,Avg CP mV,CP mV Diff,Judgment Value,Pack T1 F,
Pack T1 C,Pack T2 F,Pack T2 C,Pack T3 F,Pack T3 C,Pack T4 F,Pack T4 C,
CP1,CP2,CP3,CP4,CP5,CP6,CP7,CP8,CP9,CP10,CP11,CP12,CP13,CP14,CP15,CP16,CP17,CP18,CP19,CP20,
CP21,CP22,CP23,CP24,CP25,CP26,CP27,CP28,CP29,CP30,CP31,CP32,CP33,CP34,CP35,CP36,CP37,CP38,CP39,CP40,
CP41,CP42,CP43,CP44,CP45,CP46,CP47,CP48,CP49,CP50,CP51,CP52,CP53,CP54,CP55,CP56,CP57,CP58,CP59,CP60,
CP61,CP62,CP63,CP64,CP65,CP66,CP67,CP68,CP69,CP70,CP71,CP72,CP73,CP74,CP75,CP76,CP77,CP78,CP79,CP80,
CP81,CP82,CP83,CP84,CP85,CP86,CP87,CP88,CP89,CP90,CP91,CP92,CP93,CP94,CP95,CP96,12v Bat Amps,VIN,Hx,
12v Bat Volts,Odo(km),QC,L1/L2,TP-FL,TP-FR,TP-RR,TP-RL,Ambient,SOH,RegenWh,BLevel,epoch time,Motor Pwr(w),
Aux Pwr(100w),A/C Pwr(250w),A/C Comp(0.1MPa),Est Pwr A/C(50w),Est Pwr Htr(250w),Plug State,Charge Mode,
OBC Out Pwr,Gear,HVolt1,HVolt2,GPS Status,Power SW,BMS,OBC,Debug,Motor Temp,Inverter 2 Temp,Inverter 4 Temp,
Speed1, Speed2,Wiper Status,Torque Nm

Charging log, starting at what conditions? L1 (120VAC 12A), L2 (208VAC-240VAC 12A-30A) or DCQC

Driving log, what conditions?

If you don't mind me stripping out the Lat and Long, I could send you a few years worth as a .csv file. ~70 MB file. I can strip out other fields if you want. Do you want that much?

Oh, and what time interval do you want? Much but not all of mine is at 30 seconds per point. I know it can be done with shorter times, but not sure how fast.

[cvad1]

Hello,

I'm more interested in the first 10 columns of the header you specified. For the charging log, it would be great if you do both L1 and L2 charging. I don't really know what the driving log outputs but it would be great to have a look at it. I am aiming at a 1-minute resolution for the data in order to perform efficient analysis.

It would be great if you could send me the .csv file you specified after stripping of the lat and long. Since it has the data for a couple of years, I could analyze the variation in the performance as well.

Looking forward to your response.

Thanks,
Chinmay
cvad1@asu.edu

[WetEV]

Hello,

I'm more interested in the first 10 columns of the header you specified. For the charging log, it would be great if you do both L1 and L2 charging. I don't really know what the driving log outputs but it would be great to have a look at it. I am aiming at a 1-minute resolution for the data in order to perform efficient analysis.

It would be great if you could send me the .csv file you specified after stripping of the lat and long. Since it has the data for a couple of years, I could analyze the variation in the performance as well.

Looking forward to your response.

Thanks,
Chinmay
cvad1@asu.edu

I do not do much L1 charging. And even if I did, I'd be unlikely to have substantial logs of it. L1 charging is slow, and I'd almost never wait around for it. L2 is a bit faster, and I do have some logs of that, mostly when traveling, but far less than half of all sessions. More than half of the charging that was logged is DCQC. Let's see if anyone else has better logs.