Fiat 500 Forum banner

1 - 20 of 49 Posts

·
Registered
Joined
·
139 Posts
Discussion Starter #1
Hey,
I'd like to compile some data on the 500's out there. Get a feel for battery longevity, what helps it, what hurts it, and how the SOH, SOH-R, SOH-C are calculated. This will help everyone keep an eye on what's going on with the battery and how we can reduce the "bad" behaviors that diminish battery life.

I'd like to collect the following variables: Vehicle Year (age), Mileage at reading, Full AmpH Capacity, SOH, SOH-R, SOH-C. (I'm sure there will be other important variables like the times at temp, %, and Current which we may want to add later)

I'll collect the data in a Google Drive, and share the sheet link, so anyone can look at the data.
Data is collected by way of Google Sheets, through goo.gl/forms/PK9s8TZvpmmTcRzz1 (i'm not able to post links yet, copy and paste into browser with https then :// as prefix). (please PM me with issues on the data, sheet, or with input on what variables will be helpful)


To get the data from your BCM:
First off you'll need A way to connect a phone/tablet/laptop to your OBD Port in the car. You'll want to make sure it's compatible with step 2.

Second you'll need AlfaOBD, it's a free App on the Google Play Store. alfaobd.com The app is supported on Android and Windows PC devices.

Third, Connect your device to your Vehicle via the OBD port (left, lower side of the kick panel. Below the steering wheel)

Fourth, open AlfaOBD and select your vehicle (Fiat), select car model (500e), select function (battery management), Select control unit (Battery Pack Control Module Var.2)

Fifth, Click connect, once connected select the battery icon on the bottom of the screen. Then click Read system status. This should then begin to populate a HUGE list of variables.

Sixth, find the variables you want/need.


Hopefully this works, and helps everyone out!
 

·
Registered
Joined
·
125 Posts
What OBD II bluetooth module are you using? From what I've read, they don't all work with AlfaOBD. Also, do the sellers mind you checking their cars?

Thanks.
 

·
Registered
Joined
·
139 Posts
Discussion Starter #9
What OBD II bluetooth module are you using? From what I've read, they don't all work with AlfaOBD. Also, do the sellers mind you checking their cars?

Thanks.
I am using the OBDlinkMX (suggested by AlfaOBD, figured I have a lot of uses just beyond this, so i'll splurge on the $80 vs the $15 cheapos)

I haven't had anyone complain yet when I ask to plug in (on personal cars). On dealer cars I usually plug in on the test drive and scan them. Explaining to the salesman about batteries and how the battery SOH is more important than mileage or age usually allays their fears, the only car that the salesman was "worried" was the brand new '18 I scanned. Though the salesman didn't know it wasn't hybrid....... (he suggested I take it home, and when I said I didn't have level2 charging at home he mentioned "you can just put gas in it, right?") I'm still confused on that one.
 

·
Registered
2013 FIAT 500e
Joined
·
1,864 Posts
Sounds like it's the SALESMAN who was confused! When my boss first drove mine it took several miles of talking about the car before he realized it wasn't a hybrid. On another thread here someone mentioned the Fiat is one of the most "transparent" (ice-like) to drive. However there aren't many gas cars with such instant torque.

From data submitted so far: Cars with more miles & more years, with higher numbers than the brand new one! Still, before purchasing a used one, maybe check for full AmpH Cap. over 55 (ideally 65), & SOH-C over 80 (ideally 100).

SOH per Mile.jpg SOH per Year.jpg
 

·
Registered
Joined
·
539 Posts
how the SOH, SOH-R, SOH-C are calculated
State Of Health (and State Of Charge) are complex calculations and the subject of much research. For example, https://www.analog.com/media/en/technical-documentation/technical-articles/A-Closer-Look-at-State-Of-Charge-and-State-Health-Estimation-Techniques-....pdf. Here is what I've determined from Googling:

  • SOH-R is a measure of the battery's increase in internal Resistance compared to a new battery
  • SOH-C is a measure of the decrease in Capacity compared to a new battery
  • SOH is an aggregate value of battery health based on combining SOH-R and SOH-C in some way.
  • Measuring resistance and capacity involves fully discharging and recharging the battery. To accurately determine SOH requires making baseline measurements when the battery is new, and over time get the SOH by repeating measurements and comparing with the baseline numbers. The big challenge is how to estimate SOH in real time without full discharge/recharge cycles, which occur rarely for EV owners.
 

·
Registered
Joined
·
139 Posts
Discussion Starter #12
  • SOH-C is a measure of the decrease in Capacity compared to a new battery

Not saying you're wrong here, but in my reading the SOH-C was supposed to be the Current capacity (how much amperage, or C value) you could pull from the battery. I imagine this like a voltage drop test under load.
 

·
Registered
Joined
·
125 Posts
https:// ac.els-cdn.com/S1876610217359829/1-s2.0-S1876610217359829-main.pdf?_tid=b0f9f7b5-f721-4a37-9e12-9b547cba9a55&acdnat=1546808327_bf2c14f8ae08763c718a6c8d52efe401
- remove spaces after // for the link to work.

"Generally, the decrease of capacity and increase of internal resistance are used to define the SOH. The capacitystate of health (SOHC) is defined as the ratio of the current capacity to the original rated capacity, while the powerstate of health (SOHR) is defined as the ratio of the difference between the current internal resistance and end-of-lifevalue to the difference between original rated value and end-of-life value"
 

·
Registered
Joined
·
139 Posts
Discussion Starter #14
https:// ac.els-cdn.com/S1876610217359829/1-s2.0-S1876610217359829-main.pdf?_tid=b0f9f7b5-f721-4a37-9e12-9b547cba9a55&acdnat=1546808327_bf2c14f8ae08763c718a6c8d52efe401
- remove spaces after // for the link to work.

"Generally, the decrease of capacity and increase of internal resistance are used to define the SOH. The capacitystate of health (SOHC) is defined as the ratio of the current capacity to the original rated capacity, while the powerstate of health (SOHR) is defined as the ratio of the difference between the current internal resistance and end-of-lifevalue to the difference between original rated value and end-of-life value"
yeah, I read that.

Hard to tell if they're meaning current = "at this time" or current = Amperage.

In their table showing the SOHc VS SOHe the SOHc percentages don't add up with the Ahr they are showing.
Either i'm doing calculations wrong (likely), I don't understand how they're doing the calculations (also likely)
or, the SOHc is not the percentage of available Ahr.
 

·
Registered
Joined
·
125 Posts
I see what you mean. The values in the table don't make sense.

In this paper, the values in figures 2 and 3 pretty much correlate to the ratio of the capacity(at this time)/capacity(initial) x 100.

http:// ftp.phmsociety.org/sites/phmsociety.org/files/phm_submission/2011/phmc_11_044.pdf

In the data you have collected so far, the SOHc values seem to correlate with (full amp capacity)/65 * 100 (I only checked a few). If we had the exact initial capacity for the specific pack, I would guess the numbers would be an exact match.
 

·
Registered
2013 FIAT 500e
Joined
·
1,864 Posts
  • SOH-C is a measure of the decrease in Capacity compared to a new battery

Not saying you're wrong here, but in my reading the SOH-C was supposed to be the Current capacity (how much amperage, or C value) you could pull from the battery. I imagine this like a voltage drop test under load.
I haven't read the subsequent posts (let alone their links!) but maybe you're both right: 500e seems to show SOH-C as Current capacity, in % of new battery capacity (thereby showing the decrease in capacity, by comparison to 100%)
 

·
Registered
2013 FIAT 500e
Joined
·
1,864 Posts
Accurate determination of SOH requires periodic measurements of fully charging and fully discharging the battery – which rarely happens in consumer vehicles. A big challenge is how to estimate it in real time without doing full charge/discharge cycles.
I STILL haven't read all the posts & links but RKW's quote here seems to match the scattered data & also unfortunately may mean it's practically impossible to obtain accurate results, since it would require driving uphill to 0%, coasting to a charger, & fully charging.

Ironic that if you are concerned enough about your SOH to want to check it accurately, you have to perform a practice that is not recommended for max SOH.
 

·
Registered
Joined
·
17 Posts
data on our 2015 500e with 37,200 miles. State of Health 97.25%, SOH-R 89.41%, SOH-C 90.2%, Amp Hour Capacity 58.7. If we started with 63 AH then about a 7% loss in capacity. So, more data to throw in the plot. I think this is all in the ball park of other 2015s.

thanks,
Valerie
 
Joined
·
24 Posts
I ordered the Konnwei KW902, downloaded the free AlfaOBD (demo) app, and what a wealth of data! My 2015 500e with 23,000 miles reports in with: HV Bat State of Health 100%, HV Bat SOH -R: 92.55%, HV Bat SOH-C: 83.92%, Full Amp Hour Capacity: 54.60 Ah. I hope this is helpful.
 

·
Registered
Joined
·
139 Posts
Discussion Starter #20
I ordered the Konnwei KW902, downloaded the free AlfaOBD (demo) app, and what a wealth of data! My 2015 500e with 23,000 miles reports in with: HV Bat State of Health 100%, HV Bat SOH -R: 92.55%, HV Bat SOH-C: 83.92%, Full Amp Hour Capacity: 54.60 Ah. I hope this is helpful.
Have you put it in this form? https://goo.gl/forms/ed7FwppZ6egnWvfE2
If not please do, this puts it in one place for everyone to data mine from.

Here are the results, so you can see what other cars show. https://goo.gl/JLbRbn
 
1 - 20 of 49 Posts
Top