LeftieBiker
Posts: 7193
Joined: Wed May 22, 2013 3:17 am
Delivery Date: 31 May 2013
Location: Upstate New York, US

Re: Battery capacity question (with picture)

Sat Feb 04, 2017 7:24 pm

hyperionmark wrote:Thanks guys!

And what number should I be looking for when I see AH?


If you see 12 capacity bars and, say, 58AH or less, then I'd say it's been reset. There is a chart that shows at what AH each bars "drops." Does anyone have a link?
2013 "Brilliant Silver" SV with Premium Package and no QC, and 2009 Vectrix VX-1 with 18 Leaf cells.

The most offensive, tasteless phrase in use here is "Pulled the trigger." I no longer respond to posts that use it.

SageBrush
Posts: 1425
Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: Colorado

Re: Battery capacity question (with picture)

Sat Feb 04, 2017 8:21 pm

If brand new is 65 Ahr and the bar drops at 15% loss, that should work out to about 55 Ahr.
Every 6.25% bar after that should equal about 4 Ahr further loss

There is a wiggle room here because the bars do not match Ahr precisely.
2013 Model 'S' with QC & rear-view camera
Bought off-lease Jan 2017 from N. California with 63.9 Ahr after 22k miles
Car is now enjoying an easy life in Colorado

SageBrush
Posts: 1425
Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: Colorado

Re: Battery capacity question (with picture)

Sat Feb 04, 2017 8:41 pm

hyperionmark wrote:Thanks guys!

And what number should I be looking for when I see AH?

Here is my LeafSpy report as an example of the screen to look at. The capacity number in Ahr is top left

Image
Last edited by SageBrush on Sat Feb 04, 2017 9:20 pm, edited 6 times in total.
2013 Model 'S' with QC & rear-view camera
Bought off-lease Jan 2017 from N. California with 63.9 Ahr after 22k miles
Car is now enjoying an easy life in Colorado

cwerdna
Gold Member
Posts: 7193
Joined: Fri Jun 03, 2011 4:31 pm
Delivery Date: 28 Jul 2013
Location: SF Bay Area, CA

Re: Battery capacity question (with picture)

Sat Feb 04, 2017 8:42 pm

LeftieBiker wrote:If you see 12 capacity bars and, say, 58AH or less, then I'd say it's been reset. There is a chart that shows at what AH each bars "drops." Does anyone have a link?

I'm not sure that's a good metric. In the past day, my used 5/2013 built '13 that still has all 12 CBs and shows these stats:
AHr: 57.02
SOH: 87%
Hx: 85.52%
odo: 41,428 miles

The stats fluctuate, of course. For example, the same car was showing this on 1/27/17:
AHr: 57.94
SOH: 88%
Hx: 87.52%
odo: 41,226 miles

viewtopic.php?p=430825#p430825 has my stats when I bought it used in July 2015. I'm quite sure mine was never reset. The stats weren't out of line for a SF Bay Area for 5/2013 built '13 of that age and mileage.

viewtopic.php?p=455984#p455984 is the table.
Last edited by cwerdna on Sat Feb 04, 2017 8:51 pm, edited 4 times in total.

'13 blue Leaf SV w/premium package (owned)
'13 blue Leaf SV w/QC + LED & premium packages (lease over, car returned)
'06 Prius

lorenfb
Posts: 1391
Joined: Tue Dec 17, 2013 10:53 pm
Delivery Date: 22 Nov 2013
Leaf Number: 416635
Location: SoCal

Re: Battery capacity question (with picture)

Sat Feb 04, 2017 8:45 pm

LeftieBiker wrote:
lorenfb wrote:
hyperionmark wrote:What would I even look for on Leaf Spy?


It's simple. Just check the SOC (state of charge), Ahrs, and health. From these data, you'll be able to determine
the overall condition of the battery. If you have more time, you can check the battery cells' conditions. At minimum,
though, are the SOC & Ahrs (full battery available capacity (Ahrs) = Ahrs / SOC).


No, ignore the SOC as it doesn't matter except to show the upper charge limit, which would require the car being tested be fully charged. The SOH is normally the really important figure, but if a BMS reset is suspected, then the AH number is the most important.


Read the post again! To calculate the present condition of the battery, i.e. the Ahrs, when fully charged,
one needs to determine the present Ahrs at the time of measurement divided by the present SOC at the
time of measurement. This is then compared to what was the condition of the battery when new at 100%
SOC, i.e. the Ahrs. One then has a relative measure of battery capacity loss, i.e. it obviates the issue of a BMS
reset.

How is it that Sagebrush who just recently acquired his Leaf has a better understanding of how to evaluate
a used Leaf's battery?

SageBrush
Posts: 1425
Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: Colorado

Re: Battery capacity question (with picture)

Sat Feb 04, 2017 9:16 pm

lorenfb wrote:How is it that Sagebrush who just recently acquired his Leaf has a better understanding of how to evaluate
a used Leaf's battery?
Don't hold me up as any standard -- I've been lurking for a long time before I bought my car.

And now, perhaps to put my foot in my mouth ...
Do the different LeafSpy pages shows different Ahr numbers ?
I know the first page AHr result has to be normalized to a full SoC;
But how about the page I show above -- the 'battery cells' report. Is that AHr reading already normalized ?
Last edited by SageBrush on Sat Feb 04, 2017 9:32 pm, edited 2 times in total.
2013 Model 'S' with QC & rear-view camera
Bought off-lease Jan 2017 from N. California with 63.9 Ahr after 22k miles
Car is now enjoying an easy life in Colorado

LeftieBiker
Posts: 7193
Joined: Wed May 22, 2013 3:17 am
Delivery Date: 31 May 2013
Location: Upstate New York, US

Re: Battery capacity question (with picture)

Sat Feb 04, 2017 9:19 pm

First, I stated that I wasn't sure about the 58AH, and asked for a link to the chart. Second, SOC by itself isn't the most important stat. I now understand that it's used to calculate relative capacity, but I think a gross discrepancy in AH vs bars is the easiest way for a newbie to determine whether or not the BMS was reset, while test driving a used Leaf. So the best number we can give the OP is an AH range that is valid for 12 capacity bars, and below which a reset is indicated. Would that lowest number be 57.0? 56.5?
2013 "Brilliant Silver" SV with Premium Package and no QC, and 2009 Vectrix VX-1 with 18 Leaf cells.

The most offensive, tasteless phrase in use here is "Pulled the trigger." I no longer respond to posts that use it.

SageBrush
Posts: 1425
Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: Colorado

Re: Battery capacity question (with picture)

Sat Feb 04, 2017 10:59 pm

I want to encourage all people who are considering buying a used LEAF to buy the full version of LeafSpy

[*]This program is saving your bacon. $15 is the best bargain you will ever be granted
[*]IIRC, only the pro version shows the array of cell voltages. You do not want to buy a car with a weak cell(s)
2013 Model 'S' with QC & rear-view camera
Bought off-lease Jan 2017 from N. California with 63.9 Ahr after 22k miles
Car is now enjoying an easy life in Colorado

lorenfb
Posts: 1391
Joined: Tue Dec 17, 2013 10:53 pm
Delivery Date: 22 Nov 2013
Leaf Number: 416635
Location: SoCal

Re: Battery capacity question (with picture)

Sun Feb 05, 2017 11:14 am

LeftieBiker wrote:First, I stated that I wasn't sure about the 58AH, and asked for a link to the chart. Second, SOC by itself isn't the most important stat. I now understand that it's used to calculate relative capacity, but I think a gross discrepancy in AH vs bars is the easiest way for a newbie to determine whether or not the BMS was reset, while test driving a used Leaf. So the best number we can give the OP is an AH range that is valid for 12 capacity bars, and below which a reset is indicated. Would that lowest number be 57.0? 56.5?


Presently my Leaf with 44K miles has 51.3 Ahrs when fully charged (SOC=100%) and 12 bars. The first bar
now drops at about 48 - 49 Ahrs while driving. Since new (12/1/13) no special charging approach has been
used, i.e. 100% during 5 week days and 2 -3 QCs per week. The Ahrs were not evaluated when delivered until
about 4K miles (61 Ahrs). I assume, as SageBrush mentions, that when it was delivered to the dealer from
the factory it had about 65 Ahrs (65A X 370V = 24kWhrs).

While driving, the Ahrs are never lower than 18 - 19 Ahrs the result of trip planning and the use of QCs or L2
access via my customers using the Leaf EVSE via multiple EVSE plug adapters. Based on my typical driving
(~ 2 miles per Ahr), I continually calculate my range and basically never use the GOM. So now with about
51 Ahrs (SOC = 100%) minus 19 (lowest allowed Ahrs), my present expected/allowed range is about 60 miles,
requiring prior knowledge of QC locations. LeadDD is continually connected to monitor the Ahrs during
driving. A BT dongle is carried in the glovebox to utilize LeafSpy Pro for detailed diagnostics, e.g. read & reset
fault codes if a problem occurs, e.g. a QC fails to initiate charging.

lorenfb
Posts: 1391
Joined: Tue Dec 17, 2013 10:53 pm
Delivery Date: 22 Nov 2013
Leaf Number: 416635
Location: SoCal

Re: Battery capacity question (with picture)

Sun Feb 05, 2017 11:38 am

SageBrush wrote:
lorenfb wrote:How is it that Sagebrush who just recently acquired his Leaf has a better understanding of how to evaluate
a used Leaf's battery?
Don't hold me up as any standard -- I've been lurking for a long time before I bought my car.

And now, perhaps to put my foot in my mouth ...
Do the different LeafSpy pages shows different Ahr numbers ?
I know the first page AHr result has to be normalized to a full SoC;
But how about the page I show above -- the 'battery cells' report. Is that AHr reading already normalized ?


1. "Do the different LeafSpy pages shows different Ahr numbers ?"
They can be, if they have been evaluated at various SOCs or for some metric being calculated over time.

2."I know the first page AHr result has to be normalized to a full SoC;
But how about the page I show above -- the 'battery cells' report. Is that AHr reading already normalized ?"
When evaluating the present Ahrs of the battery, one always needs to know what the SOC is at that point
in time, e.g. if the present SOC is 100%, then the Ahrs is at its max value.

With regard to your image of LeafSpy data (64.55 Ahrs & 97%), mostly likely the Ahrs shown are based on
SOC = 100%, i.e. it been "normalized" to use that term. I will verify this with my Leaf & LeafSpy.
Presently my LeafDD indicates about 32 Ahrs (not fully charged). LeafSpy indicates 53 Ahrs and SOC = 60%
with the same image as displayed upthread (53 Ahrs X 60% = 32 Ahrs). So the percentage shown is the
present SOC of your battery, i.e. it then had about 63 Ahrs (64.55 X 97%) of available capacity left from
the last charge.

With regard to your Ahrs, you have basically a new 24kWh Leaf!

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