GregH
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Leaf Number: 26967
Location: Irvine, CA

Re: Capacity vs Health

Mon Jun 24, 2013 9:16 am

garygid wrote:So, other than being scaled differently, the CAP and Health
seem to be basically the same thing, right?

What is the scale factor?
Is it a constant?
Perhaps the scale factor changes with... age?
Great graph btw.. Gary the Ah CAP and Health seem to be very similar but it's hard to say which (if either) the car is using to determine capacity loss. need. more. data.
'17 blue Volt Premier w/ACC
'12 SL black Leaf
'11 SL blue Leaf
RAV4-EV 2002-2005
Gen1 & Gen2 EV1 1997-2003
PV 2.4Kw, 10kWh lithium battery SCE TOU-DA

klapauzius
Posts: 1658
Joined: Thu Feb 24, 2011 4:19 pm
Delivery Date: 25 Jan 2011
Leaf Number: 0197
Location: Seattle, Wa

Re: Capacity vs Health

Mon Jun 24, 2013 11:18 am

The scale factor is 1.8 and a linear fit yields:

health (%)=1.8 *cap -19

GregH
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Location: Irvine, CA

Re: Capacity vs Health

Mon Jun 24, 2013 2:13 pm

klapauzius wrote:The scale factor is 1.8 and a linear fit yields:

health (%)=1.8 *cap -19
Yes! and that -19 offset is interesting.. Looks like you need to knock about 11Ah off the Ah capacity in order for it scale linearly with the health. Notice on the graph the health highs and lows are higher and lower than the Ah capacity..
adspguy wrote:Cap vs health:
Image
Perhaps health is a percentage of original USEABLE capacity? Since we can't really touch the top or bottom few percent SOC... Perhaps this is a better mark of capacity loss as it might better reflect loss in range?
Last edited by GregH on Mon Jun 24, 2013 2:56 pm, edited 1 time in total.
'17 blue Volt Premier w/ACC
'12 SL black Leaf
'11 SL blue Leaf
RAV4-EV 2002-2005
Gen1 & Gen2 EV1 1997-2003
PV 2.4Kw, 10kWh lithium battery SCE TOU-DA

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Stanton
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Re: Capacity vs Health

Mon Jun 24, 2013 2:33 pm

These images aren't coming through (or they've been removed), but I'm following this thread with great interest. I look at that second page of LeafDD periodically.
2011 Blue Ocean SV w/floor mats & window tint
12v LiFePO4 battery & FIAMM 74100 horns
Wet Okole seat covers (front)
Tor's low-power heater mod
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3G modem upgrade
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Battery Pack replaced (Rev E) @51 months and 41k miles

klapauzius
Posts: 1658
Joined: Thu Feb 24, 2011 4:19 pm
Delivery Date: 25 Jan 2011
Leaf Number: 0197
Location: Seattle, Wa

Re: Capacity vs Health

Mon Jun 24, 2013 4:50 pm

I tried to fit a generalized linear model to capacity, using the data posted here. So basically

cap in ah = a* SOC+b*max temp + c

But it does not fit well... There is a very tentative inverse relationship of cap vs. temperature, but I suspect it is not linear....Maybe some exponential model could work, i.e.

ah=A*exp(-b*max_temp)
but the data look quite noisy, so this fit does not produce great results either...

adspguy
Posts: 94
Joined: Tue Apr 10, 2012 1:12 pm
Delivery Date: 23 Apr 2012
Leaf Number: 018978
Location: Newton, MA

Re: Capacity vs Health

Wed Jun 26, 2013 10:00 am

And the cap/health roller coaster continues......
Image
and
Image

I've recently changed to 100% charging daily due to a longer commute during the week. Also, some days I take multiple data points, like when I arrive at work, and then just before I leave 9 hours later.

klapauzius
Posts: 1658
Joined: Thu Feb 24, 2011 4:19 pm
Delivery Date: 25 Jan 2011
Leaf Number: 0197
Location: Seattle, Wa

Re: Capacity vs Health

Wed Jun 26, 2013 6:15 pm

I think we need to wait to get more data...
At the moment it appears that there is just a tentative connection....Am I hallucinating or is the drop in cap lagging behind the temperature increases?

GlennD
Posts: 1493
Joined: Sun Dec 18, 2011 7:14 pm
Delivery Date: 20 May 2013
Leaf Number: 410357
Location: Anaheim

Re: Capacity vs Health

Thu Jul 04, 2013 11:05 am

It seems like before the update the health was about the same as the SOC %. Now it is much lower.
This is the readings after 100%.
Image
Image
:
2013 Pearl White SL Premium
Traded for a Cirrus White 2014 Mercedes B (totaled)
2016 Urano Gray eGolf SEL w/ drive assist
Loved the VW but it sat too low for my old body
Back to a Cirrus White 2017 B250e
White Ioniq limited.It sits just fine

GregH
Posts: 860
Joined: Fri Jul 01, 2011 4:16 pm
Delivery Date: 13 Jun 2011
Leaf Number: 26967
Location: Irvine, CA

Re: Capacity vs Health

Thu Jul 04, 2013 11:13 am

What are the numbers in the first photo (other than Vpack)? If the 2nd photo is Ah Capacity and Health that seems odd.. 85.67% Health sounds really low for a 61.35Ah pack. Just the other day I was at 93.57% Health with 62.1166Ah Capacity in my car.
'17 blue Volt Premier w/ACC
'12 SL black Leaf
'11 SL blue Leaf
RAV4-EV 2002-2005
Gen1 & Gen2 EV1 1997-2003
PV 2.4Kw, 10kWh lithium battery SCE TOU-DA

adspguy
Posts: 94
Joined: Tue Apr 10, 2012 1:12 pm
Delivery Date: 23 Apr 2012
Leaf Number: 018978
Location: Newton, MA

Re: Capacity vs Health

Thu Jul 04, 2013 11:22 am

Hey GregH, do your cap and health values vary like mine?

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