MyVoltCapacity Android app via developer=MyVoltApp

38387 Views 86 Replies 27 Participants Last post by comforted.prune, 11 d ago

scottf200

Discussion Starter · Dec 16, 2019 (Edited)

5

A developer (not me) created a basic UI interface to get the "value the hybrid module calculates from your battery charge cycles to track how much overall capacity is left." They indicate it is "not about usable capacity!"

Appears the concept is so you can monitor your car over time. They are considering some changes to the app possibly to help the user track their values.

There is a FB group where it was discussed and folks were posting their results:
1) Model year
2) Ah Capacity
3) Wh Capacity
4) at what mileage
5) if Ampera

I took a sample of the values and put them in a graph (see bottom).

All his apps: https://play.google.com/store/apps/developer?id=MyVoltApp&hl=en_US
MyVoltCapcity in above list: https://play.google.com/store/apps/details?id=com.myvoltapp.MyVoltCapacity&hl=en

MyVoltCapacity (Early Access)
MyVoltAppAuto & Vehicles
This app is in development. It may be unstable.
This app is compatible with all of your devices.
This app reads the remaining overall capacity of your vehicles battery pack.
This app was designed for the Chevrolet Volt with the OBDLink MX bluetooth adapter.
WHAT'S NEW
Version 1.0 Beta

Image: https://i.imgur.com/gf04TC2.jpg

Image: https://i.imgur.com/sKdoOm8.jpg

Wh Capacity:
Image: https://i.imgur.com/sJ8M7kp.jpg

Image: https://i.imgur.com/QOQwIgx.jpg

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scottf200

Discussion Starter · #2 · Dec 16, 2019

I'd be happy to add your results to the list to get a better view where different Model Years stand.

1) Model year
2) Ah Capacity
3) Wh Capacity
4) at what mileage
5) if Ampera

scottf200

Discussion Starter · #3 · Dec 21, 2019

No body wants to share their results or even look at this. It seems this forum in general likes to ignore the degradation topic as much as possible (in general) and people often say there is no degradation which is illogical based on chemistry.

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marcusm

· #4 · Dec 21, 2019 (Edited by Moderator)

scottf200 said:
No body wants to share their results or even look at this. It seems this forum in general likes to ignore the degradation topic as much as possible (in general) and people often say there is no degradation which is illogical based on chemistry.
<snip> graph from above

Thanks, I’ll try it with our volts. GM does a pretty good job “disguising” the degradation from showing up for a good while in usable capacity with the buffers, but as a matter of chemistry, no doubt it happens every day.

Sent from my iPhone using Tapatalk

Mugrunty

· #5 · Dec 21, 2019

Here you go! 🙂 seems a little low compared to what I've been seeing with the Torque app. Even with manual calculations it should be higher than 16.8KWh. I made another post about degradation and my data. But yes, not very popular to discuss battery degradation with actual test data.

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scottf200

Discussion Starter · #6 · Dec 21, 2019

Mugrunty said:
Here you go! 🙂 seems a little low compared to what I've been seeing with the Torque app. Even with manual calculations it should be higher than 16.8KWh. I made another post about degradation and my data. But yes, not very popular to discuss battery degradation with actual test data.

Thanks!
1) Model year
<snip>
4) at what mileage
<snip>

hickman55

· #7 · Dec 22, 2019

2016 build date 10/15

2016 (10/15)
55420

Black Text Font Darkness Light

Black Text Font Darkness Light

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JuneBug

· #8 · Dec 22, 2019

scottf200 said:
I'd be happy to add your results to the list to get a better view where different Model Years stand.

1) Model year: 2015
2) Ah Capacity: 44.1
3) Wh Capacity: 14704
4) at what mileage: 38,224
5) if Ampera: No

Mugrunty

· #9 · Dec 22, 2019

scottf200 said:
Mugrunty said:

Here you go! 🙂 seems a little low compared to what I've been seeing with the Torque app. Even with manual calculations it should be higher than 16.8KWh. I made another post about degradation and my data. But yes, not very popular to discuss battery degradation with actual test data.

Click to expand...

Thanks!
1) Model year
<snip>
4) at what mileage
<snip>

Oops!
Year 2018
15,056 miles. 83% electric miles.

scottf200

Discussion Starter · #10 · Dec 22, 2019

Thanks folks. I updated the Original Post with all the current data.

scottf200

Discussion Starter · #11 · Dec 27, 2019

Any more folks want to supply some numbers? 17s, 18s, 19 or any earlier.

Synovialbasher

· #12 · Dec 27, 2019

Just found your thread. Here ya go!

1. 2013
2. 40.2
3. 13404
4. 157926 miles
5. Volt

So my understanding is that the 3rd value (Wh) is the actual capacity remaining, which would be 13.4 Kwh in my case. Is this correct?

scottf200

Discussion Starter · #13 · Dec 27, 2019 (Edited)

2

Synovialbasher said:
Just found your thread. Here ya go!
...
So my understanding is that the 3rd value (Wh) is the actual capacity remaining, which would be 13.4 Kwh in my case. Is this correct?

Battery degradation is based on age and cycles. I think you can get an idea if you are far outside of norms. The value appears to be want the GM drivetrain team's formula estimates your overall capacity. It is hard to estimate degradation so nothing is hard and fast. you can see how you compare to other 2013s. Pretty good considering how many miles and kW you are taking out and pushing in (regen and charging).

From first post:

A developer (not me) created a basic UI interface to get the "value the hybrid module calculates from your battery charge cycles to track how much overall capacity is left." They indicate it is "not about usable capacity!"

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wordptom

· #14 · Dec 28, 2019 (Edited by Moderator)

scottf200 said:
Battery degradation is based on age and cycles. I think you can get an idea if you are far outside of norms. The value appears to be want the GM drivetrain team's formula estimates your overall capacity. It is hard to estimate degradation so nothing is hard and fast. you can see how you compare to other 2013s. Pretty good considering how many miles and kW you are taking out and pushing in (regen and charging).

From first post:

The app developer may say "it is not about usable capacity," but I’m not sure if the app’s wH Capacity is a capacity number that should be compared to the car’s original full battery capacity.

My understanding is the wH capacity is obtained by using the formula (aH) * (V) = (wH)

Since we don’t have a table listing the aH values of the Volt batteries when new (so that we could determine for ourselves, V = wH/aH, for the various Volt models to see what value of V was used for all Volt models, and if V is the same for both Gen 1 and Gen 2 Volts), the value of V that is used by this app when calculating wH is important.

The app seems to be using V = 333.4+ for all model years to calculate the wH readout. Your chart also includes another accepted value, V = 355.2.

The "actual remaining capacity" for Synovialbasher’s 2013 Volt is thus calculated to be either 13.4 kWh or 14.3 kWh, depending on which value of V you use. That’s quite a difference to an owner thinking in terms of a car that came with a 16.5 kWh battery...

In one old thread in a posting dated 1-29-2012, WopOnTour posted, "GM officially lists the cell voltage as 3.7V nominal, making nominal pack voltage 355.2V ".

According to the app, the one 2018 Volt appearing in the list has already lost over 8% of capacity (16871/18400 = 91.7%). Using the higher value for V, however, indicates the 2018 Volt’s battery is still at 17973/18400 = ~97.7% of original capacity.

Perhaps the app’s developer would care to comment further on how the wH Capacity calculation was derived, and how to avoid thinking in terms of "degradation" when comparing the kWh number derived from the app’s wH number to the car’s original kWh capacity.

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Synovialbasher

· #15 · Dec 28, 2019

wordptom said:
The "actual remaining capacity" for Synovialbasher’s 2013 Volt is thus calculated to be either 13.4 kWh or 14.3 kWh, depending on which value of V you use. That’s quite a difference to an owner thinking in terms of a car that came with a 16.5 kWh battery...

This is how I saw it too. Some battery degredation is to be expected, and with the buffer built in, I have not noticed anything that makes it seem like the battery has lost capacity. Heck, adding a few more PSI to the tires to counteract the winter cold gives me an extra 2-3 miles of range, all else being equal. Granted, the nut behind the wheel is the main factor.

Although my volt is on the higher side with mileage for the other 2013s that were polled, I'm wondering why it doesn't have more degredation. I'd be curious to see the region where the other ones are from. Despite having a battery temperature control system, my Volt lives in Michigan where it's cooler half the year. Even with liquid cooling, I wonder if higher temperature regions experience greater degredation, and if so, by how much? My volt is always plugged in when not in use, and at my previous job it was always plugged in at work too (meaning the battery cooling/heating would run when needed). It would be neat to factor in a few more variables to determine how the battery will degrade.

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bourgous

· #16 · Dec 28, 2019

The battery pack in my first gen '13 died and I'm looking for a used 2nd gen. I'm probably going out of state to get one, do you think it would be worth avoiding one from a hot climate? Say from south florida or the southwest? The death of my first gen has me a bit skittish.

scottf200

Discussion Starter · #17 · Dec 28, 2019 (Edited)

2

wordptom said:
The app developer may say "it is not about usable capacity," but I’m not sure if the app’s wH Capacity is a capacity number that should be compared to the car’s original full battery capacity.

My understanding is the wH capacity is obtained by using the formula (aH) * (V) = (wH)

Since we don’t have a table listing the aH values of the Volt batteries when new (so that we could determine for ourselves, V = wH/aH, for the various Volt models to see what value of V was used for all Volt models, and if V is the same for both Gen 1 and Gen 2 Volts), the value of V that is used by this app when calculating wH is important.

The app seems to be using V = 333.4+ for all model years to calculate the wH readout. Your chart also includes another accepted value, V = 355.2.

The "actual remaining capacity" for Synovialbasher’s 2013 Volt is thus calculated to be either 13.4 kWh or 14.3 kWh, depending on which value of V you use. That’s quite a difference to an owner thinking in terms of a car that came with a 16.5 kWh battery...

In one old thread in a posting dated 1-29-2012, WopOnTour posted, "GM officially lists the cell voltage as 3.7V nominal, making nominal pack voltage 355.2V ".

According to the app, the one 2018 Volt appearing in the list has already lost over 8% of capacity (16871/18400 = 91.7%). Using the higher value for V, however, indicates the 2018 Volt’s battery is still at 17973/18400 = ~97.7% of original capacity.

Perhaps the app’s developer would care to comment further on how the wH Capacity calculation was derived, and how to avoid thinking in terms of "degradation" when comparing the kWh number derived from the app’s wH number to the car’s original kWh capacity.

The original app only had Ah. Later Wh was added so I had samples with both values. I used the both values to calc the V as you surmised from my header label. I then used the average of W to calculate the missing Wh when I only had samples with Ah.

I don't know if Ah in the app is calculated from various PIDs or not. My impression is that is a calculation the author spent some time on. There are some PID documents on the volt. I copied one in late 2015. It is below.

Google sheet: VoltPIDs Copy 2015-11-29
https://docs.google.com/spreadsheets/d/1X_J2ZoZh3MYd3I0IfiNILnamvzwUn9rI6cUTYNEyayc/edit?usp=sharing
In above I see: Battery Capacity, HV Amps, HV Battery Current, HV Volts, & Hybrid Pack Remaining (SOC). Not sure used in Ah or Wh app output.

The current shared one looks quite a bit different. Perhaps one allowed it to be downloaded and used by Torque directly or something.
Googlesheet: Volt PIDshttps://docs.google.com/spreadsheets/d/1HgWCnosdRqZYoWHEl7ylAxjxv4UFVeisWiR7gcr8H6I/edit#gid=0

I got the 355.2v from the InsideEVs article but thanks for the other reference and 3.7v too.

Related to your % of original calculation idea (16871/18400 = 91.7%) in the first image below I played with a calculation using the 67% (87-20) which I think is close to true for Gen 1. Not sure about Gen 2 or individual years. That didn't work out. In the 2nd image below I added a % related to the max kWh (F related to E & H related to G). Sometimes is is > 100% tho.

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scottf200

Discussion Starter · #18 · Dec 28, 2019 (Edited)

Related to the Volt Google PID documents I pointed to above and the battery capacity. See the NOTE below.

FYI, there is a Google doc on the Bolt too.

Name: Chevrolet Bolt OBD2 PIDs
https://docs.google.com/spreadsheet...3MdcGcmDk3scAP8_muSy-BlXPc/edit#gid=946940079

!Battery Capacity Guess
Bat Cap Est
2241A3
((A*256)+B)/30
0
65
kWh
7E4
NOTE: This is essentially just a present capacity estimate, and will fluctuate over time and with temperature.
You cannot use this as a health estimate.

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z80

· #19 · Dec 30, 2019

Here's mine but it seems to be the lowest of 2013's so far...

1) 2013
2) 36.6 Ah
3) 12203 Wh
4) 77780 miles
5) No

Scan conditions: Checked in the morning after a low of 58 degrees F, full charge having ended 9 hours earlier but still on a L2 charger. Turned car on to scan.

Was this a bad time to test it or was I in error in procedure?

scottf200

Discussion Starter · #20 · Dec 30, 2019

z80 said:
Here's mine but it seems to be the lowest of 2013's so far...

1) 2013
2) 36.6 Ah
3) 12203 Wh
4) 77780 miles
5) No

Scan conditions: Checked in the morning after a low of 58 degrees F, full charge having ended 9 hours earlier but still on a L2 charger. Turned car on to scan.

Was this a bad time to test it or was I in error in procedure?

Not sure if there is a consistent procedure. I don't think I turned the cars on when I did ours. I think I just had to open the door.

I would try it with the car off (not started via button). I would try it when you are not charging at the end of the day. Basically see it is close to consistent.

Have you had service bulletins applied related to the battery (cell balancing)?
Do you ever get 'Reduced Propulsion Power'?
What is your daily driving? In other words, do you run the battery down to 0 miles left regularly?

1 - 20 of 87 Posts