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Re: LeafDD - Dash Display for Leaf

Posted: Sat Nov 11, 2017 4:40 pm
by lorenfb
lorenfb wrote:
jjeff wrote:^^^ interesting, I haven't noticed that. How hard and for how long do you have to push on the accelerator to get that number to appear? Also how long does it display after it appears? I take it a higher internal resistance is worse than a lower one, what is a typical number and what number might mean a battery is getting weaker? My '12 is down to 9 bars and only has a capacity of 47 and Hx around 51, I'd imagine it's internal resistance would be quite a bit higher than a Leaf with a good battery.


1. It takes about 10 seconds for it to sample the data.
2. It stays as long as you stay on that screen. Once the screen is changed, It will not be shown the next time that screen is displayed.
3. Yes, just like a lead-acid battery, a higher the resistance indicates aging and more heat developing as a function of load or charging.
4. The output resistance does change over time. I'll post my data taken over the last 3 years later today.


Here are the battery resistance data:

11/20/14 -13,700 miles, 76 mohms per LeafDD, 20 Deg, 73% SOC
11/27 -13,800 miles, 67 mohms per LeafDD, 25 deg, 63% SOC
11/30 - 13,900 miles, 56 mohms per LeafDD, 27 deg, 71% SOC
12/2 - 14.100 miles, 55 mohms per LeafDD, 28 deg, 67% SOC
12/16 - 14,500 miles, 89 mohms per LeafDD, 15 deg, 93% SOC
12/27/14 - 14,800 miles, 103 mohms per LeafDD, 11 deg, 24% SOC
3/10/15 - 17,400 miles, 60 mohms per LeafDD, 30 deg, 73% SOC
3/14 - 17, 550 miles, 56 mohms per LeafDD, 32 deg, 47% SOC
4/14 - 19,100 miles, 59 mohms per LeafDD, 25 deg. 38% SOC
5/4 - 19,989 miles, 64 mohms per LeafDD, 24 deg. 48% SOC
5/15 - 20,400 miles, 73 mohms per LeafDD, 20 deg. 41% SOC
5/22 - 20,700 miles, 58 mohms per LeafDD, 28 deg. 50% SOC
12/10/15 - 28,000 miles, 90 mohms per LeafDD, 19 deg. 92% SOC
4/5/16 - 32,000 miles, 74 mohms per LeafDD, 24 deg, 55% SOC
5/16 - 33,700 miles,89 mohms per LeafDD, 22 deg, 47% SOC
5/16 - 33.700 miles, 58 mohms per LeafDD, 31 deg, 76% SOC
10/5 - 39,300 miles, 100 mohms per LeafDD, 22 deg, 50% SOC
10/6 - 39,400 miles, 61 mohms per LeafDD, 30 deg, 51% SOC
10/7 - 39,500 miles, 80 mohms per LeafDD, 25 deg, 56% SOC
10/15 - 40,000 miles, 71 mohms per LeafDD, 27 deg, 45% SOC
10/30 - 41,000 miles, 74 mohms per LeafDD, 23 deg, 66% SOC
12/26/16 - 43,000 miles, 110 mohms per LeafDD, 13 deg, 77% SOC
6/10/17 - 49,600 miles, 89 mohms per LeafDD, 19 deg, 70% SOC
7/1/17 - 51,000 miles, 62 mohms per LeafDD, 33 deg, 44% SOC
8/15/17 - 53,400 miles, 61 mohms per LeafDD, 35 deg, 57% SOC

Once these are graphed (someday), a family of curves will result with;
Y axis being resistance, X axis being temperature, with each stacked curve being an aging point in time with a negative
temperature slope.

Re: LeafDD - Dash Display for Leaf

Posted: Sun Nov 12, 2017 7:46 am
by Stanton
I didn't expect/know that the battery resistance data would vary so widely; I thought it would simply rise with age/degradation?
I assume those temps are Fahrenheit (Celsius would be too hot)?

Re: LeafDD - Dash Display for Leaf

Posted: Sun Nov 12, 2017 9:40 am
by lorenfb
Stanton wrote:I didn't expect/know that the battery resistance data would vary so widely; I thought it would simply rise with age/degradation?
I assume those temps are Fahrenheit (Celsius would be too hot)?


Those are degrees centigrade. The hottest was 35C (95F).

Re: LeafDD - Dash Display for Leaf

Posted: Wed Nov 22, 2017 6:27 pm
by IIama
Was the 3D model/STL for the enclosure ever posted? I'd like to reprint mine.

Re: LeafDD - Dash Display for Leaf

Posted: Thu Dec 14, 2017 8:18 pm
by JasonA
IIama wrote:Was the 3D model/STL for the enclosure ever posted? I'd like to reprint mine.
Yes.. I have the STL file that Greg sent me years ago... Let me find it..

Re: LeafDD - Dash Display for Leaf

Posted: Thu Dec 14, 2017 8:39 pm
by JasonA
Here you go.. Good luck!

I also have the SLDPRT file too for you SW peeps out there..
https://nofile.io/f/xHoUoWsxMdw/can-reader-housing5.STL

Re: LeafDD - Dash Display for Leaf

Posted: Thu Jan 25, 2018 12:04 am
by FalconFour
Stanton wrote:I didn't expect/know that the battery resistance data would vary so widely; I thought it would simply rise with age/degradation?
I assume those temps are Fahrenheit (Celsius would be too hot)?

Resistance correlates with temperature - a cold battery has higher resistance, which is why you lose range: energy is lost to internal resistance which results in the battery warming itself up. So it is, thankfully, a self-correcting condition... at the expense of energy.

That is also to say, outside temperature isn't the only thing affecting range. The outside temperature could be 0C/32F and if you're on a road trip with a battery plenty warmed up (in the 90F range or so), you'll still get improved mileage as you continue driving. The air resistance, though, does still increase in cold temperatures - so it takes more energy to push through the air - but it's more like driving at 55F with a warm battery at 32F. ;)

Yeah, driving a Leaf on road trips can be a bit of an exercise in engineering knowledge... but generally, fuzzy math and rough calculations can do you well, especially given the number of variables involved. :ugeek: