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TickTock
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Delivery Date: 31 May 2011
Leaf Number: 3626
Location: Queen Creek, Arizona
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What is Hx?

Mon Jul 28, 2014 6:23 am

.. or what is 7bb, Group 1, D2:D2
I realized this was a little off-topic for the "Data from the Leaf Battery App" thread so starting a new one here:
TickTock wrote:OK. Jeremy shared his CANary logs so I was able to add data from a car with significantly different ESR (he's around 90mO and I'm around 120mO). Was able to fit something fairly close if I included ESC (=1/ESR), AHr, and Temperature.

If I only use ESC, below is the closest fit I could reach:
Image
(the step function at the end of the graph is where my car's data ends and Jeremy's begins)

Adding Pack temperature to the formula it gets better:
Image

And finally adding Ah I get the best fit (I should clarify. This is the Ah capacity (proportional to SOH) - NOT the charge state) :
Image

Adding SOC had very little impact to the fit.
So the Fn I have now is:
Fn = 0.00616*(ESC+84.5) * [1-0.0011*(PackT-1.536)] * [1+0.0322*(Ah-49.4)]

Plugging in ttweed's data, assuming a pack temperature of 29C, and solving for ESC, it appears he has ~120mO ESR (TT, do you know your pack temp?). mwalsh's numbers don't compute because we know the Hx algorithm changed significantly with the P3227 update which he has avoided.

Any other CANary owners (or LEAFers with other means to measure ESR) willing to share their triplogs so we can see if this formula holds up under further scrutiny?

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TickTock
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Leaf Number: 3626
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Re: What is Hx?

Mon Jul 28, 2014 6:26 am

I tried just ESC and AH and got the following:

HxComp_ESC_Ah.jpg


Almost as good as the one with temperature also included. (RSS=.242 versus .188 for all three). Probably because AH is already modulated with temperature. So from this is appears Hx is a metric including *both* ESR and SOH (SOH is proportional to AH). In the graph, Hx is the value read from the Leaf and Hx2 is my formula. Currently:
Hx2 = 0.00595*(ESC+84.5) * [1+0.0320*(Ah-49.2)]
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JeremyW
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Leaf Number: 19136
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Re: What is Hx?

Tue Aug 05, 2014 1:47 pm

Perhaps "real world" state of health? :)
2012 SL, License plate: CHADEMO
Brusa OBC for 7.2kW L2 charging
Juke wheels w/ MXM4 tires, 10" subwoofer, tint, LEDs, LeafDD, CANary
2000 Honda Insight 5 speed for long trips

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garygid
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Re: What is Hx?

Tue Aug 19, 2014 5:52 am

Very nice work.
The formula with temperature fits your data really well.

Perhaps the thread title should be "Investigating Hx", or similar
rather than What is..?

Maybe you could detail exactly what data is being used for the
calculation. Thanks.

What is your horizontal axis, trips?

Cheers, Gary
See SOC/GID-Meter and CAN-Do Info
2011 LEAF, sold in 2015
2010 Prius, 2014 silver Tesla S
Nissan EVSE, mod to 240/120v 16A
PU: SDG&E
Solar PV: 33 x 225W -> 7 kW max AC
To Sell: X-treme 5000Li EV motorcycle

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TickTock
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Re: What is Hx?

Tue Aug 19, 2014 9:18 am

garygid wrote:What is your horizontal axis, trips?

yup

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