2013 Low Battery Capacity AHr Battery Degradation

[Computerizer]

Another datum to add to your collection: Just after VLBW, LeafSpy said I had 21 GIDs and 1.6 kWh. At turtle, it said I had 5 GIDs and 0.4 kWh. So according to Leaf Spy, I used 1.2 kWh. I drove 14 miles. I find it extremely unlikely that I got 11.7 mi/kWh, as I was intentionally trying to drive down the SOC by accelerating hard and braking hard as I drove back and forth on the road in front of my house 26 times...

I suspect that I was probably getting around 3.6 mi/kWh based on intuition. Since I went 14 miles, this would mean I used 3.9 kWh when Leaf Spy said I used 16 GIDs. This, then, may help to confirm your suspicion that these lower GIDs are bigger. A lot bigger.

I wonder if Jim can somehow detect these particular flawed LEAFs in Leaf Spy and apply corrections to the displayed information?

 

[DaveEV]

Final battery status at turtle

Well, the good news is that your AHr/HX values are going up already! I suspect it will look even better tomorrow after you charge back up.

NOW I know that 5 GIDs is my floor, and that can help, but it's still frustrating.

Don't rely on that 5 GIDs being constant. More than once a LEAF owner has been surprised by Turtle popping up earlier than expected - I suspect that's one reason the GOM goes to ---.

What does seem to be reliable is that the lowest cell-pair voltage will be right around 3.0V resting voltage, as you can see from your LEAF Spy screenshot.

 

[DaveinOlyWA]

wow that sucks.

Dave, it really doesn't suck. In fact that's the whole point of this thread, that certain 2013s show low numbers on LeafSpy BUT THAT THE PACK IS REALLY OK, just different from what we've come to expect.

sorry should have clarified. i agree with your point exactly. i posted results from my commute yesterday with MUCH better battery stats but nearly similar results (or at least nothing approaching a 10% increase...) but i did not use the very bottom of the pack only getting to 14 GID.

work needs did not allow me to experiment further so hope to get something more definitive soon and it was a bad driving day yesterday with constant significant rain...

 

[stjohnh]

TIPS FOR DRIVING BELOW VLBW:

I have two 2013 Leafs, both May built, both normal range and capacities beween about 59-61. Both w about 7000 miles on them, both turtled 3x each. I drive at least once weekly an 82 mile round trip, frequently w a few miles extra for short side trips. I drive below VLBW at least once weekly, and lose the last fuel bar about 1x each week.

The best way I have found to avoid turtle in these cases is to monitor the LeafSpy SOC down to losing the last fuel bar, and when the last fuel bar goes, monitor the lowest cell voltage. The way I drive (4.0-4.5 mi/kwh) I use the following chart: (all SOC are LeafSpy NOT dash SOC)

Dist to turtle= SOC-3miles (at about 4-4.5mi/kwh) works down to 11% SOC

LBW=23 miles to turtle, SOC=26%
VLBW=13 miles, SOC=16.5%
Last Fuel Bar disappears= 7 mile, SOC=11%, Lowest Cell Voltage=3.57

Lowest Cell Volts (car stopped for about 10 sec).
3.53=6mi to turtle
3.43=5mi to turtle
3.34=3mi
3.23=2mi
3.14=1mi
3.10=0.5miles
3.00=turtle

NOTES:The voltages are highly dependent on the load. To use the voltage chart you will need to stop the car for a few seconds to read the voltage, if you read the volts during driving, the miles left will be very inaccurate. The miles to turtle for the volts chart is for driving about 35mph. Turtle will occur at 3.00 volts, NO MATTER WHAT. SO, If you go 65mph, the battery is loaded and so miles to turtle will be MUCH less than the volt chart shown above. If you hit turtle, remember that if you turn off car you cannot restart it until battery is charged back to about 17%.

As Boomer pointed out, there is nothing wrong with the battery, Nissan has just programmed the GIDs, SOC, etc differently. They are not "wrong" just different. The problem is NOT the battery, but that the dedicated gurus on this board that have developed LeafSpy, DD, etc have not had enough information to make their instruments match the readings of the 2011 and 2012 Leafs. I strongly suggest that those with 2013 Leafs NOT use GIDs at all, way too much confusion.

Also, it is very helpful for an owner to do a range test, driving to turtle (not just near turtle) at least once, both to confirm the battery is ok and to feel comfortable driving below VLBW.

 

[Computerizer]

TIPS FOR DRIVING BELOW VLBW

Thanks for these tips! It's very helpful. I did notice that the lowest voltage was very close the 3 even, so I figured something like this could be figured out.

 

[Computerizer]

My dealer says there's an update, NTB 13-098, for the PDM, which very recently came out, and it applies to my new LEAF. Have any of you with the May-built LEAFs applied this update? If so, did it have any affect?

Thanks,
Tyrel

 

[derkraut]

As I read all these posts, I have a nagging question: Is driving all the way down to "turtle" harmful to battery life?

 

[GregH]

As I read all these posts, I have a nagging question: Is driving all the way down to "turtle" harmful to battery life?

Turtle? Possibly.. But there shouldn't be any issue driving down to 10-15Gids. As long as the lowest cell is above 3.6V there's nothing to worry about. 3.0V I'm not so sure.

Either way, if you do go that low DRIVE GENTLY!!

 

[davewill]

As I read all these posts, I have a nagging question: Is driving all the way down to "turtle" harmful to battery life?

Possibly. Certainly you should charge it back up above 20-50% as soon as you can.

 

[stjohnh]

My dealer says there's an update, NTB 13-098, for the PDM, which very recently came out, and it applies to my new LEAF. Have any of you with the May-built LEAFs applied this update? If so, did it have any affect?

Thanks,
Tyrel

Yes, it stopped the occasional partial charges I was getting.

 

[stjohnh]

As I read all these posts, I have a nagging question: Is driving all the way down to "turtle" harmful to battery life?

"Common wisdom" on these forums says it is. There is no evidence that Leafs driven to turtle damages the Leaf battery. The Nissan manual and warranty only say that the warranty is void if the car is kept discharged over 14 days. On the rare turtle I have had, I have immediately started charging.... "just in case."

Also remember that turtle is NOT a completely discharged battery, it contains a residual charge that Nissan has determined is necessary to avoid damage. Evidence from other lithium cells does indicate damage from completely discharging the cell, especially if it is not promptly recharged.

 

[Computerizer]

Yes, it stopped the occasional partial charges I was getting.

I was wondering if it fixed the specific problem this thread is about, with LEAFs built in May showing less capacity but actually having the same.

 

[stjohnh]

Yes, it stopped the occasional partial charges I was getting.

I was wondering if it fixed the specific problem this thread is about, with LEAFs built in May showing less capacity but actually having the same.

Capacity reading on LeafSpy did not change w the update. The information that came w the update notice said it was to reduce overheating of the PDM that can cause it to automatically shut off before charge is complete.

 

[DaveinOlyWA]

My dealer says there's an update, NTB 13-098, for the PDM, which very recently came out, and it applies to my new LEAF. Have any of you with the May-built LEAFs applied this update? If so, did it have any affect?

Thanks,
Tyrel

this is interesting since my LEAF reads like a 2011 and its build date is Oct which would imply mine was built with this SW fix already in place...

 

[Computerizer]

Yes, it stopped the occasional partial charges I was getting.

I was wondering if it fixed the specific problem this thread is about, with LEAFs built in May showing less capacity but actually having the same.

Capacity reading on LeafSpy did not change w the update. The information that came w the update notice said it was to reduce overheating of the PDM that can cause it to automatically shut off before charge is complete.

Oh, okay. The dealer made it sound like this was a different update than the one we applied on our other 2013 last week; but maybe I heard wrong or he was mistaken.

 

[biggsy]

Just so I would know my Leaf, I did a range test over the last two days. This was done during my commute to and from work in normal traffic at normal conservative speeds. Most of my trip is six lanes of commercial district with a 45 mph speed limit. It is 24.9 miles each way of which about 5 miles is 55mph limit. The terrain is flat, temps were mid 50's to mid 60's, tire pressure a little high at 40psi cold. Also, the end of bar 6, all of 7 and 8 and most of 9, were driven in the rain with headlights, wipers, radio, and occasional defrost to clear the windshield.

I have an S model so no cruise control and it appears Leaf Spy Pro and my speedometer do not agree. My speedometer was indicating pretty close to 45mph whenever traffic permitted but looking at the Leaf Pro log I rarely got up to 45. Does Leap Spy use GPS calculated speed or does it read speed from the can? As a side note, I pass a fixed radar site that displays your speed and it consistently shows me 2 or 3 mph lower than my dashboard indicated speed at 45mph. The radar site pretty much agrees with Leaf Spy data.

Anyway, my total over two days on one charge 114.3 miles at an indicated 5.2mi/Kwh = 21.94 usable battery. Below is the chart I compiled for each battery energy bar as they disappeared, as well as LBW, VLBW and Turtle. If anyone is interested I will be happy to send you then entire log file. I set it to 15 second updates to try to catch more information mostly about speed.

Miles after LBW=25.8, miles after VLBW=15.6, Avg speed LBW to VLBW (per Leaf Spy)= 42.7mph, avg speed VLBW to Turtle = 29.7mph.

 

[stjohnh]

I have an S model so no cruise control and it appears Leaf Spy Pro and my speedometer do not agree. My speedometer was indicating pretty close to 45mph whenever traffic permitted but looking at the Leaf Pro log I rarely got up to 45. Does Leap Spy use GPS calculated speed or does it read speed from the can? ........ If anyone is interested I will be happy to send you then entire log file. I set it to 15 second updates to try to catch more information mostly about speed.

Miles after LBW=25.8, miles after VLBW=15.6, Avg speed LBW to VLBW (per Leaf Spy)= 42.7mph, avg speed VLBW to Turtle = 29.7mph.

Great info. Can you tell us the LeafSpy capacity and SOH for your battery pack? Also, so you have the minimum cell voltages for the data at VLBW and below? I would be interested. If you have the minimum cell voltages, at what speed were the measurements taken?

My 2013 S also reads 60 mph dash when true (gps) speed is 57.

Also you hit turtle at SOC=3.0%, (a little higher SOC than my data). Since min cell voltage=3.00 is the trigger for turtle starting, it suggests you were going little faster when you hit turtle (higher speed=higher battery load= lower minimum cell voltage due to higher cell impedance at low voltages). Do you recall the details of exactly how you were driving when you hit turtle? Perhaps you were at a stop light, and stepped on the "gas" pedal when turtle started?

 

[biggsy]

Great info. Can you tell us the LeafSpy capacity and SOH for your battery pack? Also, so you have the minimum cell voltages for the data at VLBW and below? I would be interested. If you have the minimum cell voltages, at what speed were the measurements taken?

My 2013 S also reads 60 mph dash when true (gps) speed is 57.

Also you hit turtle at SOC=3.0%, (a little higher SOC than my data). Since min cell voltage=3.00 is the trigger for turtle starting, it suggests you were going little faster when you hit turtle (higher speed=higher battery load= lower minimum cell voltage due to higher cell impedance at low voltages). Do you recall the details of exactly how you were driving when you hit turtle? Perhaps you were at a stop light, and stepped on the "gas" pedal when turtle started?

As far as LeafSpy capacity, my max GIDs shown so far has been 271, starting this range test they were 268 at 100%, and SOH was 96%. I have uploaded the LeafSpy log to this link:
https://drive.google.com/file/d/0Bw6Q2jcxiaC7ZXN6S2lpT3Z5WXM/edit?usp=sharing

This is the log file after I highlighted the points where each bar was lost and calculated average speed.

As for hitting turtle, I was watching the Leaf Spy while driving slow, probably 15 - 20 mph. I noticed while driving the lowest voltage actually drops below 3.00 and then recovers as I approached a stop. At the time it actually gave me the Turtle Warning I was going maybe 10mph. My last 3 miles prior to turtle were on about a 1/2 mile section of road in my development that allowed my to get up to 35mph or so before turning around at each end without having to stop completely. Below is the screen capture from Leaf Spy after I stopped, I only went about .2 miles after turtle.

 

[biggsy]

Also, forgot to mention, for average speed between each bar I took the easy way out. I had Leaf Spy set for 15 second updates, I highlighted the first hit after each bar was lost, based on my indicated mileage, and then just averaged the speed from all the hits in between. That will drastically reduce the average speed when stopped at a red light for more than one log hit.

 

[DaveEV]

Below is the screen capture from Leaf Spy after I stopped, I only went about .2 miles after turtle.

Great data - confirms that the car goes into turtle when the lowest cell-pair gets to a resting voltage of just over 3.0V.

What's the lowest voltage you saw under load?