eyemgh
Posts: 33
Joined: Thu Oct 26, 2017 1:32 am
Delivery Date: 26 Oct 2017
Location: Ashland, OR

Re: Best and Worst Case

Sun Oct 29, 2017 8:38 am

Assuming it hasn't been reset, the bar would drop once the SoH drops below 85% wouldn't it?

eyemgh
Posts: 33
Joined: Thu Oct 26, 2017 1:32 am
Delivery Date: 26 Oct 2017
Location: Ashland, OR

Re: Best and Worst Case

Sun Oct 29, 2017 5:51 pm

Is the above a safe assumption? Maybe, more importantly, a drive to 75% SOC from full and multiplying by 4 should give a pretty accurate estimate of true range shouldn't it?

BuckMkII
Posts: 169
Joined: Sat May 06, 2017 8:04 am
Location: Seattle

Re: Best and Worst Case

Sun Oct 29, 2017 9:46 pm

eyemgh wrote:Maybe, more importantly, a drive to 75% SOC from full and multiplying by 4 should give a pretty accurate estimate of true range shouldn't it?

Range in a test drive is not the way to compare cars, since the driving conditions will not be standardized. What you really want to know is the pack's energy capacity, which is analogous to the fuel tank size in an ICE car. "Range" is simply the capacity (typically in kWh) times the specific "fuel" mileage you are seeing (in miles per kWh).

If you drove at a constant 90 MPH, your car's range would be MUCH less than if you drove at a constant 40 MPH because aero drag goes up with the square of speed. Similarly, if you were going up and down hills, with stops every block (think driving in Pacific Heights, San Francisco), your range would be less than driving in a flat region with few stops, because regeneration is not very close to 100% efficient. So, range in a test drive alone isn't going to tell you anything of much use for assessing the car's health. If the test driving conditions mimic your intended use very closely, I guess you would see how far you could go, but you would not know how "good" that car's battery is relative to others.

In principle, you can measure the pack capacity by the following method: reset all trip computers and energy histories on the dashboard and the center nav screen system. Shut off car and turn it back on to zero LeafSpy readings. Note the SOC % shown on the dashboard and in LeafSpy (which probably won't be the same, so record both). Start driving for as long as possible. You want to knock the SOC % down plenty. Fifteen to twenty miles of steady highway speed would be good; out and back along the same road so the vertical averages out but flatter is better so you don't have regeneration throwing off things. Stop and note the ending SOC % on the dashboard and in LeafSpy. Also read the mileage in miles per kWh from the dashboard or nav screen, and from LeafSpy (it's on the Summary screen, and you have to poke the little block of text above the colored bar graph several times to cycle through to it...take the Trip one with only one number, not the Charge reading with two numbers, one in parentheses.) Subtract the ending SOC from the starting SOC. Say they were 78% and 53%, so the difference is 25%. Divide that number by 100%, so the fraction of the battery you used was 0.25. Now, how much power did you use? Say you drove 19 miles at 3.9 miles per kWh. 19 miles / 3.9 miles/kWh = 4.87 kWh (energy consumed.) Divide that number by 0.25 and you get 19.5 kWh as the total capacity of the pack, which would be pretty good for a several-year-old car. I think my car holds abut 18.5 kWh, and it just lost its first bar.

I should say that, while this sounds good on paper, I'm not totally convinced it's foolproof to do this on one test drive and say you "know" the capacity of the pack. Mine actually got a better score on my first try!
2013 SV no QC, manufactured July 2013
car grew up in San Jose CA, purchased 5/31/17 in Seattle
on 6/16/17: AHr = 56.4; SOH = 86%; Hx = 84.3; ODO = 39,250
on 9/29/17: AHr = 55.3; SOH = 84%; Hx = 81.6; ODO = 41,492
bar 12 lost 8/21/17

eyemgh
Posts: 33
Joined: Thu Oct 26, 2017 1:32 am
Delivery Date: 26 Oct 2017
Location: Ashland, OR

Re: Best and Worst Case

Sun Oct 29, 2017 10:38 pm

The car is too far from me to Leaf Spy. I trust the owner. He has another EV, a solar array, and is enjoying the back and forth conversations about pack health. He in no way impresses me as a scammer. He's the original owner. The car has been driven on an ideal route and charged properly at home. It still has 12 bars, but we both suspect just, since it has 43,000 miles. We are trying to figure out how he can best verify the pack health, but I think he's just going to go get an OBD scanner and Leaf Spy it tomorrow now that he's familiar.

powersurge
Posts: 768
Joined: Wed Oct 21, 2015 10:24 am
Delivery Date: 06 Dec 2014
Location: Long Island, NY

Re: Best and Worst Case

Mon Oct 30, 2017 2:47 am

original poster is presenting an impossible question. You live 6 hours away and trust the seller.... YOU get the leafspy, drive the 6 hours and go test it...

BuckMkII
Posts: 169
Joined: Sat May 06, 2017 8:04 am
Location: Seattle

Re: Best and Worst Case

Mon Oct 30, 2017 7:13 am

How much are they asking?
2013 SV no QC, manufactured July 2013
car grew up in San Jose CA, purchased 5/31/17 in Seattle
on 6/16/17: AHr = 56.4; SOH = 86%; Hx = 84.3; ODO = 39,250
on 9/29/17: AHr = 55.3; SOH = 84%; Hx = 81.6; ODO = 41,492
bar 12 lost 8/21/17

eyemgh
Posts: 33
Joined: Thu Oct 26, 2017 1:32 am
Delivery Date: 26 Oct 2017
Location: Ashland, OR

Re: Best and Worst Case

Mon Oct 30, 2017 8:15 am

It's a 2014 SL with Premium package, original owner, 12 bars, 43000 miles, 30 mile or so daily commuter, from a moderate climate, 15 DCQCs. We agreed to $10k and he's including an unopened Juicebox 40 Pro. So, effectively, I'm paying $9400. For that configuration, assuming of course no reset, it seems like a good deal. I missed the screamin' deal window that we had about 9 months ago.

BuckMkII
Posts: 169
Joined: Sat May 06, 2017 8:04 am
Location: Seattle

Re: Best and Worst Case

Mon Oct 30, 2017 9:21 am

Yeah, if the battery is really as described, buy it! That's a way better deal than I got. OTOH, I only had to drive 15 minutes to get to the dealer.

One dealer here is showing 3 x 2014 SLs for $12,995 asking. All from Bay Area and two of them with 11 bars. If the battery checks out, you're crushing it.
2013 SV no QC, manufactured July 2013
car grew up in San Jose CA, purchased 5/31/17 in Seattle
on 6/16/17: AHr = 56.4; SOH = 86%; Hx = 84.3; ODO = 39,250
on 9/29/17: AHr = 55.3; SOH = 84%; Hx = 81.6; ODO = 41,492
bar 12 lost 8/21/17

warrenc
Posts: 78
Joined: Tue Mar 28, 2017 2:33 pm
Delivery Date: 28 Apr 2017
Leaf Number: 418438
Location: Tacoma,WA

Re: Best and Worst Case

Mon Oct 30, 2017 3:50 pm

Agreed. Sounds like a really nice car for a good price. You could pay less for a lesser car, but I doubt you'll find an SL with premium package for less in that condition. Did you ever get the CarFax? Probably less of an issue if you're buying from the original owner.
2013 Leaf SV
Tacoma, WA

DaveinOlyWA
Posts: 12332
Joined: Sat Apr 24, 2010 7:43 pm
Delivery Date: 10 Nov 2016
Leaf Number: 314199
Location: Olympia, WA
Contact: Website

Re: Best and Worst Case

Mon Oct 30, 2017 4:32 pm

eyemgh wrote:Is the above a safe assumption? Maybe, more importantly, a drive to 75% SOC from full and multiplying by 4 should give a pretty accurate estimate of true range shouldn't it?


no because you can't use the bottom of the pack. Also the actual SOC measurements from the car is not super accurate.

Based on probabilities, you ;likely have a car that is within 83% to 90% of original capacity. You could be marginally less than that or as much as 5% more than that. How far that will take you is highly subjective. Some can go 85 miles during decent Summer weather, some would struggle to go 65 miles.

Keep in mind; depending on your cold tolerance, that range will be 15-30% less in Winter. Cold isn't as much of a factor (if you leave heat off) as rain on the roads so very hard to avoid in your area.
2011 SL; 44,598 miles. 2013 S; 44,840 miles.2016 S30 (build 10/2016)"low water marks" 27,000 miles.363GID Ahr 79.13Hx95.17%kwh28.1QCs238,L2's 251
My Blog; http://daveinolywa.blogspot.com" onclick="window.open(this.href);return false;

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