281 is not the maximum SOC value

My experience shows that CV starts at around 50-55% SOC in a QC session. That's why jkirkebo only had 35kW at 60%.

1. Sometimes, charging to "100%" instead of "80%" (or lower) is important in reaching one's next destination.

2. The simplistic, non-intelligent charging profile CAN be Constant Current, Constant Voltage. However, most charge controllers these days are smarter than that, and they change (adapt) the current flow during charging to suit cell voltage, temperature, history, etc.

jkirkebo said:

I noted down the different power levels from the quick charger.

22-45% - 46kW.
60% - 35kW
68% - 30kW
75% - 25kW
80% - 20kW
86% - 15kW
93% - 10kW
96% - 8kW
98% - 6kW
100% - 4.8kW
102.5% - 2kW

Click to expand...

This is very interesting data. I hadn't expected 46 kW to be sustained for such a large portion of the SOC range.

I will note that a charge rate of 20 kW at roughly 80% SOC is significantly higher than what I normally observe from sustained regen going down "our" 5000' mountain descent at that SOC. At 80% SOC, I normally can't even sustain 10 kW of regen, even when the pack is relatively warm. (Regen is more limited when the pack is cold.)

One might ask why regen is apparently more limited than QC in terms of charge rate. Perhaps Nissan engineers wanted to avoid greater wear on the battery pack, since most of us do more regen than QC.

garygid said:

Good work, nice data, doing QC on a 2012 model, right?
If you have the Logging Port on your SOC-Meter, a CAN-Do log of the EV-CAN bus during a full QC session would be great to publish for others to examine and investigate.

Click to expand...

Sorry, no port and no laptop either. I just have a dekstop and an iPad, neither is useful for in-car logging

But I'm sure the results can be replicated with someone with access to a QC and SOC-meter ?

I would note from the data provided that the rate of charge dropped through "1C" which would be 24kW for the Leaf's approximate 24kWh pack, right about 75 to 80%. So my statement about no advantage of a 2C or 3C capable charger (as vs. a 1C charger) for the last (very very roughly) 20% holds true.

While I mentioned earlier that the Leaf's 3.3kW charger left room for a more capable charger to do that last 20% faster, I didn't put any numbers behind it. The built in charger is about 0.14C, so there is still significant advantage to the quick charger for that last 20%, in the specific case of a Leaf. Good to know... I hadn't really done that mental math and didn't realize how much of a gain a QC would have during the last 20%, as vs. the 3.3kW built in. The gap is quite large, and therefore the QC is much faster, as you folks pointed out.

Since I now have access to a QC, it is very good to see the data, do the math, and change my assumptions.



With regard to charge controllers being smarter than simple CC/CV: Agreed!! Most modern systems are smarter. But... the CC/CV rates, with CC mostly being limited by the charger's total wattage capability, and the CV being an inherent limitation of the Li chemistry, those limits still form an "upper" or "outer" range within which the smarter systems must operate. As such, they are still useful for directional calculations. As always, measurement trumps prediction, and it is REALLY NICE to have the data.

jkirkebo said:

The charger stopped by itself. This is normal QC behaviour when you start from below 50% SOC. If you start from above 50% the charge process goes to 100%. Or in this case, 102.5%

Click to expand...

What kind of QC did you use because the Blink QC seems to operate much differently than the one you used. The Blink one charges to whatever you set it to and it makes no difference at what SOC % you start from. However, I found that to get an 80% charge (78-79% actual), you have to set it to '90%', and it will charge a little faster (about 23 mins.) when you are down to two bars or less. Also, to get a 100% charge takes an additional 32 minutes (after the 90%) and it only takes it to 97% SOC. I can't get the raw numbers yet. Since QCing, I now get 81.8% for an 80% charge on L2 where as before QCing, I usually always got 76.8%. I haven't charged to 100% yet on L2 since the QCs, but the most I've gotten on L2 is 94%. I'm going to 100% charge later today/tonight for tomorrow. I'll probably get close to 100% now (Edit: I predicted correctly...99%!).
HAPPY THANKSGIVING Everyone!

LEAFfan said:

jkirkebo said:

The charger stopped by itself. This is normal QC behaviour when you start from below 50% SOC. If you start from above 50% the charge process goes to 100%. Or in this case, 102.5%

Click to expand...

What kind of QC did you use because the Blink QC seems to operate much differently than the one you used.

Click to expand...

It's made by SGTE, a french company:

http://www.sgte-power.com/produits2/page1.html

It's not possible to set the charger to anything, there is only one button on the screen labeled "start", and when it's running the button is labeled "stop" instead. Nothing else to configure. The charger will run for 60 minutes max.

In one charge I made from 10% SOC, the power started below 50KW at around 45kW because it is charging at the maximum 125A chademo can provide. As the voltage increases the power increases up to almost 50kW (394x125) and then the voltage stayed constant and the current started
to drop. The car started with 5 temperature bars and ended with the same 5, so there was no need to limit current from the temperature.

The next time I make a QC I will see if my car can go above 281 gids.

vegastar said:

In one charge I made from 10% SOC, the power started below 50KW at around 45kW because it is charging at the maximum 125A chademo can provide. As the voltage increases the power increases up to almost 50kW (394x125) and then the voltage stayed constant and the current started
to drop. The car started with 5 temperature bars and ended with the same 5, so there was no need to limit current from the temperature.

Click to expand...

Interesting. I think the carger I used was limited to 120A as it never exceeded that. I started with only 4 temperature bars, though I think it finished with 5 (not sure). I usually only see 4 bars these days.

LEAFfan said:

jkirkebo said:

The charger stopped by itself. This is normal QC behaviour when you start from below 50% SOC. If you start from above 50% the charge process goes to 100%. Or in this case, 102.5%

Click to expand...

What kind of QC did you use because the Blink QC seems to operate much differently than the one you used. The Blink one charges to whatever you set it to and it makes no difference at what SOC % you start from. However, I found that to get an 80% charge (78-79% actual), you have to set it to '90%', and it will charge a little faster (about 23 mins.) when you are down to two bars or less. Also, to get a 100% charge takes an additional 32 minutes (after the 90%) and it only takes it to 97% SOC. I can't get the raw numbers yet. Since QCing, I now get 81.8% for an 80% charge on L2 where as before QCing, I usually always got 76.8%. I haven't charged to 100% yet on L2 since the QCs, but the most I've gotten on L2 is 94%. I'm going to 100% charge later today/tonight for tomorrow. I'll probably get close to 100% now (Edit: I predicted correctly...99%!).
HAPPY THANKSGIVING Everyone!

Click to expand...

FYI, the Leaf still does take priority on the Blink QC units. If you're below 50% SOC, the Leaf will stop charging at 80% SOC, regardless of what the DC Quick Charger is set at. If you're over 50% the Leaf won't attempt to stop charging until it reaches 100%.

For reference, the few times I have charged (L2) from 80% to 100%, it took about 90 minutes (or 1 orbit . Compare that to the times the OP saw.

Also, the cells in the pack will bypass themselves when they reach full charge. This lets the other cells "catch up"--this is the "balancing act". Also, the car will terminate charging when it figures it's done. All this means that the charger can't overcharge your pack even if it wants to.

gbarry42 said:

Also, the cells in the pack will bypass themselves when they reach full charge. This lets the other cells "catch up"--this is the "balancing act".

Click to expand...

Interesting. It may have been posted, but I have missed any definitive statement that actual balancing occurs and the method used. It is assumed that balancing occurs at 100% charge, but I wonder if that is really in effect during DC quick charge. Do you have a reference for the method? Thanks.

Bill

From the service manual:

HOW TO ADJUST CELL CAPACITY
During cell capacity adjustment, the capacity of each cell is estimated based on the no-load voltage when the
system starts, and the capacities are adjusted so that they are all at the target level. The voltage of each cell is
detected inside the Li-ion battery controller. The bypass switches are then turned ON to discharge the cells
that have excess capacity. In this way, capacity adjustment by the Li-ion battery controller allows the capacity
of all cells to be fully utilized.


This followed by a diagram that shows a "bypass switch" wired in parallel with each cell. In reality, I'd be fairly certain what they show as a cell in this diagram is pysically a 2P group. All circuitry is on an ASIC inside each module. Therefore, I'd expect 2 ASICs per module.

Danal said:

From the service manual:

HOW TO ADJUST CELL CAPACITY
During cell capacity adjustment, the capacity of each cell is estimated based on the no-load voltage when the
system starts, and the capacities are adjusted so that they are all at the target level. The voltage of each cell is
detected inside the Li-ion battery controller. The bypass switches are then turned ON to discharge the cells
that have excess capacity. In this way, capacity adjustment by the Li-ion battery controller allows the capacity
of all cells to be fully utilized.


This followed by a diagram that shows a "bypass switch" wired in parallel with each cell. In reality, I'd be fairly certain what they show as a cell in this diagram is pysically a 2P group. All circuitry is on an ASIC inside each module. Therefore, I'd expect 2 ASICs per module.

Click to expand...

Thank you for that reference. So it is a discharge of high cells. And, it certainly must be the discharge of a parallel pair.

I'm enlightened :idea:

Bill

Today I restarted the L2 charging 2 times after it stopped and it reached 282 gids.

It charged from LBW to 277 gids and after 1 hour I started the charge again and in 10 minutes it reached 281 gids. Before stopping, the charging power dropped to 1 kW and climbed again to 3 kW various times. Could it be the pack balancing?

I waited another 20 minutes, started charging and in 2 minutes the charging stopped and reached 282 gids.

DarkStar said:

LEAFfan said:

What kind of QC did you use because the Blink QC seems to operate much differently than the one you used. The Blink one charges to whatever you set it to and it makes no difference at what SOC % you start from. However, I found that to get an 80% charge (78-79% actual), you have to set it to '90%', and it will charge a little faster (about 23 mins.) when you are down to two bars or less. Also, to get a 100% charge takes an additional 32 minutes (after the 90%) and it only takes it to 97% SOC. I can't get the raw numbers yet. Since QCing, I now get 81.8% for an 80% charge on L2 where as before QCing, I usually always got 76.8%. I haven't charged to 100% yet on L2 since the QCs, but the most I've gotten on L2 is 94%. I'm going to 100% charge later today/tonight for tomorrow. I'll probably get close to 100% now (Edit: I predicted correctly...99%!).
HAPPY THANKSGIVING Everyone!

Click to expand...

FYI, the Leaf still does take priority on the Blink QC units. If you're below 50% SOC, the Leaf will stop charging at 80% SOC, regardless of what the DC Quick Charger is set at. If you're over 50% the Leaf won't attempt to stop charging until it reaches 100%.

Click to expand...

I haven't tried QCing over 50% because I've always been around 8%-30% SOC when I've used it. Next week, I'll charge when it's above 50%/7 bars and I'll let you know if it doesn't stop at 80% (set to 90% on the Blink). I need to correct you though on the part about it will stop charging at 80% regardless of what the Blink is set to. When you are at 30% (actual) SOC or lower, it will shut off at 20%, 30%, 40%, 50%, 60% or which ever percentage you set it to that is under '90%' when you are under 30%. I've already done that so I know.

1. One Blink QC is described a Start/Stop only unit, another as having "Charge-To" settings.

How are the settings accessed on the "setable" Blink QC?

2. The Cell-Pair bypass is unlikely to bypass (discharge from the cell-pair) more than ABOUT one amp (4 watts), PERHAPS up to around 2 amps (8 watts). In any case, the max-bypass is "N" amps.

When a cell-pair is "full" (cannot tolerate further charging), the Pack charging current MUST drop to "N" or less amps (or, most likely, OFF), even if the "bypass" circuits on the highest cell-pairs are turned ON.

So far, we have no indication that the bypass circuits are activated WHILE actively charging the Pack. Most likely, the bypass "equalization" comes on after charging is "complete".

Although use of the bypass is possible when the LEAF is first turned ON, as part of a startup or calibration routine, the time period between ON and Driving is usually WAY too short to accomplish any "equalization".

garygid said:

1. One Blink QC is described a Start/Stop only unit, another as having "Charge-To" settings. How are the settings accessed on the "setable" Blink QC?

Click to expand...

After you enter your zipcode, it tells you to connect the charging handle, then a screen pops up with all the different percentages of charge that you may choose. To get '90%' (80% charging), you have to select 'more options' and then it shows you 90% and 100%. After you select your %, you push the 'Charge' button on the screen. It tells you at what percent SOC (actual) you started from and when it ends, tells you how much time it took and to what SOC% it is. However, when it says '90% charged, I either have 79% SOC on the gauge or 80%. The techs explained to me why I'm getting more SOC now with L2 charging (82% at 80% and 99% at 100% charging) than I used to. It's a 5% increase so far. It's definitely from QCing, but it isn't really balancing the cells per se such as with L2 charging, but it allows a higher % now because of QCing. I hope this explanation makes sense.

"the techs explained to me why"...

Did they just say "yes, it went up", or
did they actually explain WHY it went up?