My 2016 30KWh experiencee

dwl said:

I don't believe the resistance changes this much with temperature and hence used the term bounces around. The H/Hx is far more sluggish to change. I do appreciate you sharing this data as only LeafDD is providing this visibility outside the INL pulse resistance results (which incidentally do have strange answers at high and low SoC).

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You are well aware that my Leaf resistance data gathering was NOT done under controlled laboratory testing conditions, right? If you have
concerns about the reliability/accuracy of the data set presented, then you are free to develop your our data set and hypothesis.

Furthermore, it seems you still fail to understand the basics of what's been discussed in length about H/Hx, i.e. it's NOT been proposed that
it's a DIRECT measure of battery resistance, but a ratio (a percent) of battery conductance. Given your lack of any understanding and the lack
of any useful data presentation on your part, a continued discussion on this topic is a total waste of time.

lorenfb said:

it's NOT been proposed that it's a DIRECT measure of battery resistance, but a ratio (a percent) of battery conductance.

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If Hx is a linear ratio of battery conductance that may mean the 30kWh owners, like the OP that started this thread, have batteries that are significantly degraded despite many now being over 80% SoH with the update. The Hx=58.34 would suggest the battery now has 1.7x the resistance of new if linear which hopefully isn’t correct and it is some other measure.

dwl said:

The Hx=58.34 would suggest the battery now has 1.7x the resistance of new if linear which hopefully isn’t correct and it is some other measure.

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You're guessing again! When you were in school, didn't you learn to not guess when solving problems? Again, where are your data?

Hopeless!

lorenfb said:

dwl said:

The Hx=58.34 would suggest the battery now has 1.7x the resistance of new if linear which hopefully isn’t correct and it is some other measure.

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You're guessing again! When you were in school, didn't you learn to not guess when solving problems? Again, where are your data?
Hopeless!

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I am asking for guidance from those who may have other information. I have heard you loud and clear - many times. The point of forums is to collate various views, not insist that the person asking the question must do all their own research or is not permitted to pose an hypothesis for discussion. Please stop shouting.

dwl said:

The point of forums is to collate various views, not insist that the person asking the question must do all their own research or is not permitted to pose an hypothesis for discussion.

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A proposed theory has been presented with supporting data about H/Hx. The burden is on you to provide alternate data which refutes
what you claim to be erroneous about H/Hx. What is your hypothesis and where are the data to suppose it? A limited data set and simple
grade school math is all that's needed. There's a very limited set of key battery parameters the BMS has access to, e.g. battery voltage
loaded/unloaded, cell voltages, battery cell temps, and battery load/charging currents, upon which to evaluate the battery over time to
determine battery degradation.

The challenge is the OP for this thread, like some others, is sceptical of the health of their battery. We know Nissan will replace under warranty when 4 bars are lost but no other metric (apart from failed cells) seems to be available. The Hx value from the 30kWh cars seems low and more like is seen with older cars, not a 2016.

I have gone through an old Leaf Spy log and when my Hx on my 2014 was around 93 the resistance, based on the method used in LeafDD (wait for period of low current, then assess when load is applied), was around 0.10 ohms which aligns with the 2013 pulse test results from Idaho National Labs.

I was hoping someone with a 30kWh car, like the topic of this thread, might have some further insight with a degraded Hx. As I have a 24kWh a lot of measurements of mine to try and calibrate Hx wouldn’t help.

dwl said:

I have gone through an old Leaf Spy log and when my Hx on my 2014 was around 93 the resistance, based on the method used in LeafDD (wait for period of low current, then assess when load is applied), was around 0.10 ohms which aligns with the 2013 pulse test results from Idaho National Labs.

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So what does that prove with just having a single data point? Nothing. Besides, statement is somewhat confusing.

Facts:
1. H/Hx does NOT change with varying battery temperature. Battery resistance has a negative temperature coefficient.
2. H/Hx decreases with battery age and is correlated with SOH indicating battery degradation.
3. H/Hx does not change with varying current loads on the battery.

lorenfb said:

A proposed theory has been presented

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Your hypothesis sounds very reasonable to me, although I would not really object to it being characterized as an educated guess.

SageBrush said:

lorenfb said:

A proposed theory has been presented

Click to expand...

Your hypothesis sounds very reasonable to me, although I would not really object to it being characterized as an educated guess.

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And hopefully others can provide further insight.

lorenfb said:

dwl said:

I have gone through an old Leaf Spy log and when my Hx on my 2014 was around 93 the resistance, based on the method used in LeafDD (wait for period of low current, then assess when load is applied), was around 0.10 ohms which aligns with the 2013 pulse test results from Idaho National Labs.

Click to expand...

So what does that prove with just having a single data point? Nothing. Besides, statement is somewhat confusing.

Facts:
1. H/Hx does NOT change with varying battery temperature. Battery resistance has a negative temperature coefficient.
2. H/Hx decreases with battery age and is correlated with SOH indicating battery degradation.
3. H/Hx does not change with varying current loads on the battery.

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A subset of my data posted a number times on MNL:

32 deg, 3/14 - 56 (18K)
33 deg, 7/17 - 62 (51K)

25 deg, 4/14 - 59 (19K)
26 deg, 6/18 - 84 (65K)

20 deg, 5/15 - 73 (20K)
18 deg, 4/18 - 110 (62K)

As one can observe from the data, battery resistance (mohms) increases with battery age/mileage, but to a lesser extent at higher temperatures.

lorenfb said:

Facts:
1. H/Hx does NOT change with varying battery temperature. Battery resistance has a negative temperature coefficient.

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We know that after successive rapid charges, or the difference between summer and winter, the SoH and the Hx rises. The SoH rise is understood to be because the battery temperature has increased and the battery has more capacity. What evidence do you have that the Hx measurement (as reported by Leaf Spy) doesn’t also increase with temperature, noting that it is a more time weighted measurement than mohms on LeafDD?

dwl said:

lorenfb said:

Facts:
1. H/Hx does NOT change with varying battery temperature. Battery resistance has a negative temperature coefficient.

Click to expand...

We know that after successive rapid charges, or the difference between summer and winter, the SoH and the Hx rises. The SoH rise is understood to be because the battery temperature has increased and the battery has more capacity. What evidence do you have that the Hx measurement (as reported by Leaf Spy) doesn’t also increase with temperature, noting that it is a more time weighted measurement than mohms on LeafDD?

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Whose we? And what are the extent of the changes to refer to? As always, you make statements without presenting ANY data.
Again, where are YOUR data! The more you post, the more illogical you sound. Without any data, whatever you post
is becoming nothing more than hyperbole.

lorenfb said:

dwl said:

lorenfb said:

Facts:
1. H/Hx does NOT change with varying battery temperature. Battery resistance has a negative temperature coefficient.

Click to expand...

We know that after successive rapid charges, or the difference between summer and winter, the SoH and the Hx rises. The SoH rise is understood to be because the battery temperature has increased and the battery has more capacity. What evidence do you have that the Hx measurement (as reported by Leaf Spy) doesn’t also increase with temperature, noting that it is a more time weighted measurement than mohms on LeafDD?

Click to expand...

Whose we? And what are the extent of the changes to refer to? As always, you make statements without presenting ANY data.
Again, where are YOUR data! The more you post, the more illogical you sound. Without any data, whatever you post
is becoming nothing more than hyperbole.

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I belong to multiple forums that discuss Leafs and I thought I was reflecting consensus that as the batteries warm up they hold more capacity and this is matched with an increase in SoH and Hx. However, I appreciate that you wish to have evidence with each of the posts, hence this is one of many examples where someone has observed an increase in SoH (and note Hx also risen in both cases) when doing multiple successive rapid charges: https://www.facebook.com/groups/NZEVOwners/permalink/2068839933383310/ and the community has confirmed the reason for increase in parameters.

I apologise to the OP for this thread getting pulled off the original topic and will stay silent.

Checked H/Hx values today as a function of temperature:

T1 - 24 C (75 F), H/Hx - 69.7
T2 - 35 C (95 F), H/Hx - 70.1

delta H/Hx = 0.6 %
delta Temp (deg C) = + 46 %

Actual battery resistance values:

6/18 - 65K, 26 C, R = .084 ohms
8/17 - 53K, 35 C, R = .061 ohms

delta R = - 27%
delta Temp (deg C) = + 35%

And what would one infer about H/Hx, i.e. are they temperature dependent as is the case for the actual battery resistance?
There's really no guessing needed.

lorenfb said:

Checked H/Hx values today as a function of temperature:

Actual battery resistance values:

6/18 - 65K, 26 C, R = .084 ohms
8/17 - 53K, 35 C, R = .061 ohms

delta R = - 27%
delta Temp (deg C) = + 35%

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I don't have any opinion in this matter, but I'm surprised that a kelvin scale is not used.

SageBrush said:

lorenfb said:

Checked H/Hx values today as a function of temperature:

Actual battery resistance values:

6/18 - 65K, 26 C, R = .084 ohms
8/17 - 53K, 35 C, R = .061 ohms

delta R = - 27%
delta Temp (deg C) = + 35%

Click to expand...

I don't have any opinion in this matter, but I'm surprised that a kelvin scale is not used.

Click to expand...

As an exercise for some who may be interested, i.e. maybe a more scientific approach but would mask the effect.

Checked H/Hx values today as a function of temperature:

T1 - 24 C (75 F), H/Hx - 69.7
T2 - 35 C (95 F), H/Hx - 70.1

delta H/Hx = 0.6 %
delta Temp (deg C) = + 46 %

Actual battery resistance values:

6/18 - 65K, 26 C, R = .084 ohms
8/17 - 53K, 35 C, R = .061 ohms

delta R = - 27%
delta Temp (deg C) = + 35%

And what would one infer about H/Hx, i.e. are they temperature dependent as is the case for the actual battery resistance?
There's really no guessing needed.

Click to expand...

Temp coefficient of H/Hx; 70.1 - 69.7 / 35 -24 = .04 / deg C = ~ 0

Temp coefficient of battery resistance; .061 - .084 / 35 - 26 = - .003 ohms / deg C (- 3 mohms / deg C)