[wonderbolt]

I started a Google sheet, that anyone can edit, to help track users Bolt reported Battery capacity. I previously posted a link to it in one of the threads but it quickly became buried with other posts. To make it easy to find and contribute to I am giving it it's own thread.

https://docs.google.com/spreadsheets/d/1ZIgmv9f_QHJ3DDzKWDz_b4k8Yg7HvMn3oeAFbuuqAEw/edit?usp=sharing

For info on how to read battery capacity please see this thread

 

[discodanman45]

I think another important column to have is temperature. From the information I have read and graphs I have seen, capacity of the battery is dependent on temperature. I don't know if the software reads battery temperature, but ambient temperature could be used. My battery capacity has always been low and I think it would depress me to start logging it. I haven't seen much degradation and I don't want to stress over it. I am at 45,000 miles and I still use hilltop reserve and drive my Bolt 130 miles a day. On a good day I have 35% capacity left and on a cold day I have 20% capacity left. I guess if it degrades I will just charge to 100%...

 

[Paul Gipe]

I've posted two measurements: when I first began using Torque Pro, and recently when I crossed 10,000 miles.


Paul

 

[cranial1963]

Which capacity calc are y'all using? ((A*256)+B)*0.035 or ((A*256)+B)/30?

 

[wonderbolt]

Which capacity calc are y'all using? ((A*256)+B)*0.035 or ((A*256)+B)/30?

the default calculation assumed by the author of the Bolt PIDs table, I have not modified the calculation

 

[wonderbolt]

I think another important column to have is temperature. From the information I have read and graphs I have seen, capacity of the battery is dependent on temperature. I don't know if the software reads battery temperature, but ambient temperature could be used. My battery capacity has always been low and I think it would depress me to start logging it. I haven't seen much degradation and I don't want to stress over it. I am at 45,000 miles and I still use hilltop reserve and drive my Bolt 130 miles a day. On a good day I have 35% capacity left and on a cold day I have 20% capacity left. I guess if it degrades I will just charge to 100%...

Feel free to enter a temperature column if you like and specify what temp should be logged, I have not recorded that but guess I could look at historic ambient temperatures for the dates I logged the capacity data...

 

[wonderbolt]

thanks for the forum members contributing some data points, glad to see @GJETSON that your battery capacity has bounced up a little...

 

[GJETSON]

thanks for the forum members contributing some data points, glad to see @GJETSON that your battery capacity has bounced up a little...

Interesting, but not useful. Now if my usable capacity went up, that would be nice.

 

[wonderbolt]

looks like @GJETSON has been diligent about tracking and logging his Bolt battery capacity, and others of us, not so much ;-) I just updated mine today, if anyone else is interested in logging or just reviewing the data collected to date please see my first post in this thread.

 

[ArizonaJon]

I started a Google sheet, that anyone can edit, to help track users Bolt reported Battery capacity. I previously posted a link to it in one of the threads but it quickly became buried with other posts. To make it easy to find and contribute to I am giving it it's own thread.

https://docs.google.com/spreadsheets/d/1ZIgmv9f_QHJ3DDzKWDz_b4k8Yg7HvMn3oeAFbuuqAEw/edit?usp=sharing

For info on how to read battery capacity please see this thread

I went to your link on how to read battery capacity. I have never used an odb, etc. so this will take some study.
However, I have a question. From previous posts, I understood that with a 2019 Bolt you can not read out the battery capacity with a odb. If this is true, then there is no reason for me to buy a odb. Can you or someone else let me know if you can now read out the battery capacity on a 2019 Bolt?

Thanks for any help you can give.

 

[GJETSON]

No. You cannot see the battery capacity PID on a 2019 Bolt.

 

[wonderbolt]

Yes, disappointingly GM has locked down the ability to read the capacity, I am sure the dealer still can, but seems reading the capacity with OBD2 is is a feature of the 2017 Bolt. I updated my reading in the table linked in the first post yesterday, it has bounced around more than I would have expected but is currently reading 59.7kWh. I did just have a few DCFC events from a recent road trip, and it has been very pleasantly warm this Summer in Upstate NY.

The Bolt just loves the warm weather, as do I, and my efficiency has been registering 4.0 m/kWh even driving "with traffic"

 

[Paul Gipe]

I've just posted my one-year mark with TorquePro and ~two years of ownership. Bouncing around low to mid 59s. Could someone plot the data posted. I am not familiar with this charting program and I could do it manually but someone's probably a geek with Google. I plot my own records and will post them shortly in a separate post. Gist, degradation exists, is slow, and beats the **** out of Nissan.

Paul

 

[wesley]

I've been tracking the battery capacity data extensively, with the numbers based on my own calculation formula as described in this thread:

Detailed battery monitoring results up to 24,099 km

My Bolt EV reached the 1 year milestone a couple of days ago, so I gathered up all the data I've been collecting over all these times and made some graphs and analyses. First of all, the car has been driven for 24,099.4km (14,974.7 miles) for its first 365 days. It's not quite as extensive as...

www.chevybolt.org

There are now over 700 data points in the spreadsheet that I manage and the numbers fluctuate quite often so I tend to try to average things out. The most recent monthly graph looks like this:

At the current 30,097km (18,701 mile) mark, the raw battery capacity data stands at 1,767. This should be equivalent to 58.9kWh on the original formula and 56.49kWh on my own formula.

 

[bww129]

From the information I have read and graphs I have seen, capacity of the battery is dependent on temperature.

A battery technically has a fixed capacity, it is the charge relative to the capacity, often called RSoC (Relative State of Charge or sometimes just SoC), which varies over time/temperature that we are interested in.

The main reason batteries don't like cold temperatures is because it slows down the chemical reaction. Fortunately, the Bolt engineers (like Tesla's, not like Nissan's) were smart enough to include active battery conditioning (via liquid heating/cooling) on the Bolt. This helps keep the battery temperature in an optimal range for increased life and performance from the cells.

Lots of good reading about this topic online.

 

[bww129]

Here are just a few (couldn't add links to my first post on the forum):

Temperature effect and thermal impact in lithium-ion batteries: A review

Lithium-ion batteries, with high energy density (up to 705 Wh/L) and power density (up to 10,000 W/L), exhibit high capacity and great working perform…

www.sciencedirect.com

Effect of Temperature on the Aging rate of Li Ion Battery Operating above Room Temperature - Scientific Reports

Temperature is known to have a significant impact on the performance, safety and cycle lifetime of lithium-ion batteries (LiB). However, the comprehensive effects of temperature on the cyclic aging rate of LiB have yet to be found. We use an electrochemistry-based model (ECBE) here to measure...

www.nature.com

https://www.plarad.de/fileadmin/downloads/FAQ_related%20to%20lithium%20ion%20rechargeable%20battery%20care_DA1_en_0216.pdf

 

[phxsmiley]

Just posted my Bolt Capacity PID tracking for the last couple of years. Before this car, I had a 2011 Nissan Leaf for 6 years, same climate and usage, and the degradation was much worse than what I've experienced with the Bolt. The Leaf capacity degraded by approximately 40% in 2 years time, hence I had 3 replacement batteries (another story). However, as others have noted, the Bolt capacity PID seems to fluctuate quite a lot. In my case, all the capacity loss appears to come during our Phoenix-area hottest months. But, there's not a lot of data points to show a clear trend yet.

 

[Sean Graham]

A battery technically has a fixed capacity, it is the charge relative to the capacity, often called RSoC (Relative State of Charge or sometimes just SoC), which varies over time/temperature that we are interested in.

The main reason batteries don't like cold temperatures is because it slows down the chemical reaction. Fortunately, the Bolt engineers (like Tesla's, not like Nissan's) were smart enough to include active battery conditioning (via liquid heating/cooling) on the Bolt. This helps keep the battery temperature in an optimal range for increased life and performance from the cells.

Lots of good reading about this topic online.

Tesla took it to the next level though. They intentionally run the motor inefficiently in order to generate more heat. That's pretty amazing.

 

[bww129]

Definitely clever to run current through the motor windings to heat the coolant and then transfer the heat to the cells.

Not sure why GM didn't do this, but they could in future designs.

 

[bww129]

However, as others have noted, the Bolt capacity PID seems to fluctuate quite a lot. In my case, all the capacity loss appears to come during our Phoenix-area hottest months. But, there's not a lot of data points to show a clear trend yet.

Temperature has a large effect on the relative capacity of the cells. Take a Samsung ICR18650-26F cell as an example - not the same cells used in the Bolt but it is a Lithium based cell. The official datasheet from Samsung specifies the 100% capacity rating at 25C, but when the temperature is 0C (32F) or 40C (104F) the relative capacity drops to 80%. At -10C (14F) the capacity drops to 50%. If you want to log relative capacity data for the pack you also need to record the cell temperature because the relative capacity data will be skewed if the temperatures are all over the place.