If they can charge it to 100% before he leaves with it, and reset the trip meter and energy economy display, that should give you most of what you need.
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2013 Leaf SV losing battery capacity checked with LeafSpy lite
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Note the SoC and reset the trip meter at the start of the trip (leaving the dealership)briscobully said:SageBrush said:Possible ? Surebriscobully said:I'm dying to get to that 2013 SL with the Feb 2013 build date and LeafSpy it! Is it possible that a Feb build with 26k miles realistically showing 12 bars still?
Likely ? I think not
LeafSpy will not clue you in to a reset. Only a decent range test drive* (say, of at least 30 miles) would let you sort out the real battery health.
*
Reset the trip meter for the test drive. This will also show you the consumption rate (in miles/kWh) for the test drive.
kWh = 1/consumption rate * distance traveled
Compare the SoC drop of the test drive to the kWh consumed. A battery in good shape drops less than 5% SoC per kWh
So I may have convinced the sales rep to bring the car to me (long story) is there anything I can have them do that will help me with testing the battery as explained above? He's got about a 20 mile trip to me and don't know if I will have time to do another 30 miles to check it out. Thx
Do you understand the rationale of the test ? I can try to explain it differently.
briscobully
Well-known member
Sagebrush
I do understand the test but can I rely on the car's SOC value as i won't be leaving the dealership with the car. I'll have to rely on the rep/dealership to fully charge and reset the values on the car before he brings it to me.
Should I do or work a different calculation in this case? Thx
I do understand the test but can I rely on the car's SOC value as i won't be leaving the dealership with the car. I'll have to rely on the rep/dealership to fully charge and reset the values on the car before he brings it to me.
Should I do or work a different calculation in this case? Thx
You can use any SOC, as long as you know for sure what it is, and realize it will be within a full percentage either way. I figured having them charge it until it shuts off at 100% was the best way to guarantee a known starting charge.
alozzy
Well-known member
You can estimate the health of the battery fairly well by doing a short-ish range test:
With the above information, you can estimate the kWh capacity of the battery:
Step 1 - Calculate kWh consumed by trip:
distance (miles)/efficiency (miles/kWh) = usage (kWH)
Step 2 - Calculate approximate pack capacity:
Since the above is the kWh usage for 25% SOC drop, 100% estimate would be just 4 times that #
For example, if you drove 20 miles over a 25% SOC drop and average 4.5 miles/kWh, then:
20 miles / 4.5 miles/kWh = 4.44 kWh consumed for trip
Then, multiply that number by 4 (i.e. 17.7 kWh) to get the estimated pack capacity in kWh.
Note that none of the above relies on LeafSpy data, which is why it's useful...
A brand new pack is around 21 kWh useable, so LeafSpy SOH should be about 84% in the example. If instead it was >90% then a BMS reset would be a strong possibility.
Having stated all of the above, a BMS reset on a 2013 would be pretty obvious anyways because virtually no 2013s are likely to have an SOH >90% at this point.
However, a used 2015 that was driven in a hot climate and had its BMS unscrupulously reset then exported across states, would be more likely to fool a potential buyer. That's because most 2015s in moderate climates would still have >93% SOH.
That's the purpose of a range test - to weed out BMS reset LEAFs.
FYI, before you buy any LEAF, make sure you know its history and where it was first sold. I personally would never buy a LEAF that lived out most of its existence in a hot climate - unless it was dirt cheap and very likely to qualify for a free replacement pack.
- Note the current state of charge (SOC) BEFORE you start driving
- Reset the energy economy gauge and trip counter BEFORE you start driving
- Drive on a highway, in good weather, maintaining 50 mph until the state of charge has dropped by 25% from the SOC you noted earlier
- Get off the highway ASAP and note how many miles you drove and the energy economy reading on the dash
With the above information, you can estimate the kWh capacity of the battery:
Step 1 - Calculate kWh consumed by trip:
distance (miles)/efficiency (miles/kWh) = usage (kWH)
Step 2 - Calculate approximate pack capacity:
Since the above is the kWh usage for 25% SOC drop, 100% estimate would be just 4 times that #
For example, if you drove 20 miles over a 25% SOC drop and average 4.5 miles/kWh, then:
20 miles / 4.5 miles/kWh = 4.44 kWh consumed for trip
Then, multiply that number by 4 (i.e. 17.7 kWh) to get the estimated pack capacity in kWh.
Note that none of the above relies on LeafSpy data, which is why it's useful...
A brand new pack is around 21 kWh useable, so LeafSpy SOH should be about 84% in the example. If instead it was >90% then a BMS reset would be a strong possibility.
Having stated all of the above, a BMS reset on a 2013 would be pretty obvious anyways because virtually no 2013s are likely to have an SOH >90% at this point.
However, a used 2015 that was driven in a hot climate and had its BMS unscrupulously reset then exported across states, would be more likely to fool a potential buyer. That's because most 2015s in moderate climates would still have >93% SOH.
That's the purpose of a range test - to weed out BMS reset LEAFs.
FYI, before you buy any LEAF, make sure you know its history and where it was first sold. I personally would never buy a LEAF that lived out most of its existence in a hot climate - unless it was dirt cheap and very likely to qualify for a free replacement pack.
briscobully
Well-known member
Very thorough, thanks so much! Ill let everyone know the results.
FYI, before you buy any LEAF, make sure you know its history and where it was first sold. I personally would never buy a LEAF that lived out most of its existence in a hot climate - unless it was dirt cheap and very likely to qualify for a free replacement pack.
Or, better still, already had that new pack installed recently.
I appreciate the detailed instructions for the OP, but two comments:
The starting SoC can be anything really; you just have to know the value.
It does not matter how you drive, the car speed, etc. That is the point of knowing the consumption rate during the test.
For the test, if we know the distance driven, the SoC drop during the test, and the consumption rate during the test, we can calculate the capacity (in kWh) of a full battery. Nothing else is needed and no other variables matter.
Note though that this is not a perfect test for many reasons, the most important being that the LEAF gauges are not the best and SoC drop is not entirely linear. So the longer the test, the better. I view it as a good screening test to find battery resets.
The starting SoC can be anything really; you just have to know the value.
It does not matter how you drive, the car speed, etc. That is the point of knowing the consumption rate during the test.
For the test, if we know the distance driven, the SoC drop during the test, and the consumption rate during the test, we can calculate the capacity (in kWh) of a full battery. Nothing else is needed and no other variables matter.
Note though that this is not a perfect test for many reasons, the most important being that the LEAF gauges are not the best and SoC drop is not entirely linear. So the longer the test, the better. I view it as a good screening test to find battery resets.
alozzy said:You can estimate the health of the battery fairly well by doing a short-ish range test:
- Note the current state of charge (SOC) BEFORE you start driving
- Reset the energy economy gauge and trip counter BEFORE you start driving
- Drive on a highway, in good weather, maintaining 50 mph until the state of charge has dropped by 25% from the SOC you noted earlier
- Get off the highway ASAP and note how many miles you drove and the energy economy reading on the dash
With the above information, you can estimate the kWh capacity of the battery:
Step 1 - Calculate kWh consumed by trip:
distance (miles)/efficiency (miles/kWh) = usage (kWH)
Step 2 - Calculate approximate pack capacity:
Since the above is the kWh usage for 25% SOC drop, 100% estimate would be just 4 times that #
For example, if you drove 20 miles over a 25% SOC drop and average 4.5 miles/kWh, then:
20 miles / 4.5 miles/kWh = 4.44 kWh consumed for trip
Then, multiply that number by 4 (i.e. 17.7 kWh) to get the estimated pack capacity in kWh.
Note that none of the above relies on LeafSpy data, which is why it's useful...
A brand new pack is around 21 kWh useable, so LeafSpy SOH should be about 84% in the example. If instead it was >90% then a BMS reset would be a strong possibility.
Having stated all of the above, a BMS reset on a 2013 would be pretty obvious anyways because virtually no 2013s are likely to have an SOH >90% at this point.
However, a used 2015 that was driven in a hot climate and had its BMS unscrupulously reset then exported across states, would be more likely to fool a potential buyer. That's because most 2015s in moderate climates would still have >93% SOH.
That's the purpose of a range test - to weed out BMS reset LEAFs.
FYI, before you buy any LEAF, make sure you know its history and where it was first sold. I personally would never buy a LEAF that lived out most of its existence in a hot climate - unless it was dirt cheap and very likely to qualify for a free replacement pack.
Based upon my experience with both 2011 and 2015, the dashboard instrumentation is not accurate enough to make these calculations definitive. The calculations will give information to compare with data obtained through other means.
I suggest you have the dealer charge the car fully and reset all of the trip displays on the dash (both trip odometers, mi/kWh, average speed, and distance/time). Ask the sales representative to step through and write down all of the display information along with SOC bars (should be 12), battery temperature bars, ambient temperature (from eyebrow display), time (from eyebrow display), and odometer immediately prior to departure. Write down all of these same readings when the car arrives (do not reset any of them) and take Leaf Spy readings. Let Leaf Spy log data while you drive (if you have the Pro version), take as long of test drive as you can, write down all readings from the dash, and take Leaf Spy readings. Then post the data here for help with interpretation. This method will give three data points to compare (two trip segments and the overall trip).
Edited to add: As Sagebrush noted, the dashboard instrumentation is not necessarily linear. That is why I recommend not resetting the displays so that you have data from one long trip and two shorter segments.
briscobully
Well-known member
LeftieBiker said:FYI, before you buy any LEAF, make sure you know its history and where it was first sold. I personally would never buy a LEAF that lived out most of its existence in a hot climate - unless it was dirt cheap and very likely to qualify for a free replacement pack.
Or, better still, already had that new pack installed recently.
Question. Will a new battery pack 'always' show up on a carfax report or only in a service history? I've see lots of carfax reports show recall work on many occasions...
alozzy said:A brand new pack is around 21 kWh useable, so LeafSpy SOH should be about 84% in the example. If instead it was >90% then a BMS reset would be a strong possibility.
Agree. Or 50 < Ahrs < 55
alozzy said:Having stated all of the above, a BMS reset on a 2013 would be pretty obvious anyways because virtually no 2013s are likely to have an SOH >90% at this point.
Agree, but probability not zero.
alozzy said:However, a used 2015 that was driven in a hot climate and had its BMS unscrupulously reset then exported across states, would be more likely to fool a potential buyer. That's because most 2015s in moderate climates would still have >93% SOH.
And your basis for that statement is? So your logic is that a higher SOH is more believable in cooler climate?
SageBrush said:Alozzy is right about the SOH in my 2013 LEAF. It is at 89%
I have no idea how it will change in the next couple of months as winter thaws. Presumably somewhere between 85-95% ;-)
Do you believe that a BMS reset can set the SOH to any value, e.g. 85%, other than just 100%?
It's possible that a BMS reset could have been done at some point in time and the vehicle driven such that the SOH is now 85-95%.
No, and I do not understand how that is related to my post.lorenfb said:SageBrush said:Alozzy is right about the SOH in my 2013 LEAF. It is at 89%
I have no idea how it will change in the next couple of months as winter thaws. Presumably somewhere between 85-95% ;-)
Do you believe that a BMS reset can set the SOH to any value, e.g. 85%, other than just 100%?
Regarding the reset, I'm under the impression that the initial read is 100% and then with driving over a few weeks (maybe a couple of months ?) the SOH settles down to the pre-reset value. So it is not the SOH value in and of itself (unless it is 100%) that makes a reset suspect, but a SOH value considerably higher than normative for the peer group.
----------
My car fits the mold of a reset: It arrived with a LeafSpy reading of 64 Ahr and 99.6% SOH, and over 6 months lost 10% of each value. I don't think my car had an intentional reset because the dealer showed me other cars with poorer readings and the current readings after 15 months of ownership are still quite good and at worse represent a pre-reset baseline. All in all, we are treading in very poorly understood waters.
In any case, my earlier post was meant to be a bit of humor: alozzy doubts a 2013 LEAF will be found that has over 90% SOH. My car *almost* meets the threshold (and obviously is not affected by any possible reset now.) And may yet, if the SOH improves as the weather warms up a bit.
SageBrush said:lorenfb said:SageBrush said:Alozzy is right about the SOH in my 2013 LEAF. It is at 89%
I have no idea how it will change in the next couple of months as winter thaws. Presumably somewhere between 85-95% ;-)
Do you believe that a BMS reset can set the SOH to any value, e.g. 85%, other than just 100%?
SageBrush said:No, and I do not understand how that is related to my post.
It was a general question, as some may believe such.
SageBrush said:Regarding the reset, I'm under the impression that the initial read is 100% and then with driving over a few weeks (maybe a couple of months ?) the SOH settles down to the pre-reset value.
Right, but not easy to do on the part of a Nissan dealer, i.e. putting miles on the Leaf. Yes, maybe an independent car lot if it had the time
and access to a Leaf diagnostic tool (Consult II) and whether that function can even be performed at the dealer level (without a logon to
Nissan corporate). Can you imagine what the press would do to Nissan, if it knew that were actually occurring at a dealer level?
SageBrush said:So it is not the SOH value in and of itself (unless it is 100%) that makes a reset suspect, but a SOH value considerably higher than normative for the peer group.
True.
SageBrush said:My car fits the mold of a reset: It arrived with a LeafSpy reading of 64 Ahr and 99.6% SOH, and over 6 months lost 10% of each value. I don't think the car had an intentional reset because the dealer showed me other cars with poorer readings and the current readings are still quite good. All in all, we are treading in very poorly understood waters.
Valid points.
briscobully
Well-known member
SageBrush said:Alozzy is right about the SOH in my 2013 LEAF. It is at 89%
I have no idea how it will change in the next couple of months as winter thaws. Presumably somewhere between 85-95% ;-)
What build month is your 2013? As stated, this one I'm looking at is Feb.
briscobully said:SageBrush said:Alozzy is right about the SOH in my 2013 LEAF. It is at 89%
I have no idea how it will change in the next couple of months as winter thaws. Presumably somewhere between 85-95% ;-)
What build month is your 2013? As stated, this one I'm looking at is Feb.
He undoubtedly has a later build "Wolf" pack. The earlier Canary pack wouldn't have 12 bars at this point under any conditions found outside of Northern Europe or Northern Canada, unless it was kept in an air conditioned garage and only driven in cooler weather..
alozzy
Well-known member
Rather than respond to all the comments about my test methodology, it's not intended to be super accurate. I know the on-board instrumentation isn't perfect...
It's only value is to a prospective buyer who is considering a LEAF that matches all these criteria:
It would be pointless to do a range test if LeafSpy shows 82% SOH, mediocre AHr, and there are 11 capacity bars on the dash - those numbers are obviously believable for an older LEAF. A BMS reset would result in much better metrics...
In other words, if LeafSpy is showing "too good to be true" metrics, then the range test will confirm if you just won the lottery or if the LEAF is a lemon.
It's only value is to a prospective buyer who is considering a LEAF that matches all these criteria:
- There are 12 capacity bars showing on the dash
- LeafSpy is showing a high SOH that would put the pack in the top 10% percentile or better
- A prospective buyer wants some peace of mind that the LeafSpy metrics are accurate and that the LEAF has not been tampered with (ie BMS reset)
It would be pointless to do a range test if LeafSpy shows 82% SOH, mediocre AHr, and there are 11 capacity bars on the dash - those numbers are obviously believable for an older LEAF. A BMS reset would result in much better metrics...
In other words, if LeafSpy is showing "too good to be true" metrics, then the range test will confirm if you just won the lottery or if the LEAF is a lemon.
stjohnh
Well-known member
Out of curiosity, I just checked the capacity of my 11 bar, 2013 S, using Alozzy's instructions. Did it exactly as he specified, except drove 60mph, not 50.
Got: starting soc=48, ending=23 =>25% used
distance=19.9 miles, efficiency=4.6
This gives: (19.9/4.6)x4=17.2 kwh capacity
17.2/21 (usable new pack)= 81% of new capacity
LeafSpy says 83% SOH. Looks like a good, no gadgets needed, way to get estimated battery pack capacity for those trying to be sure the battery in their prospective purchase is about what is showing (i.e. BMS reset was likely done if a car with the above results has all 12 bars).
Got: starting soc=48, ending=23 =>25% used
distance=19.9 miles, efficiency=4.6
This gives: (19.9/4.6)x4=17.2 kwh capacity
17.2/21 (usable new pack)= 81% of new capacity
LeafSpy says 83% SOH. Looks like a good, no gadgets needed, way to get estimated battery pack capacity for those trying to be sure the battery in their prospective purchase is about what is showing (i.e. BMS reset was likely done if a car with the above results has all 12 bars).
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