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Discussion Starter #1
Totally sucked into the EV world, the wife and I now have both a Spark EV and Bolt EV.

We love both cars and each is quite different, but I noticed one thing the Spark EV has which the Bolt does not: the ability to measure battery degradation.

With Spark, you KNOW how much your battery has degraded. There is a feature on the spark where you can figure out quite easily how much your battery has deteriorated over time/travel. Mine has lost more than 15% in eighteen months and 17K miles.

I can only imagine we have our legal brethren to thank for this. GM doesn't want its customers running to them with warranty claims on their batteries.

That said, I'm disappointed we cannot measure our inevitable loss of capacity. It would be interesting if nothing else. It would also help plan longer distance travel.

On a different note, the Spark is waaaaaay more fun to drive, if less safe. We intend to keep both for the time being. And not to knock the Bolt, certain features of it are well appreciated. Especially the hilltop charging feature, which may extend battery life by not charging to full.

My guess is the Spark EV is going to survive in EV "gear queer" communities. It's torque is insane and easily increased even more. The Bolt is an "adult" car. Very capable albeit plain vanilla.

I just wish we could measure the battery degradation of the Bolt.....Thoughts???
 

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In what way? Seems like a simple task to me to look at range / consumption and compare to advertised. Am I missing something?
Since the 20 bar graph is as close to the Bolt gets in terms of showing battery capacity, what happens as the battery loses capacity? Say when it has dropped to 80 % of 60 kWh as it ages? Maybe GM doesn't want us to know.

A harsh approach would be to fill it up, drive it to close to zero and measure how much energy goes in to recharge it to full.
Range is a tricky proposition, because it depends on speed, temperature, driving conditions in a complex way.:nerd:
 

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In what way? Seems like a simple task to me to look at range / consumption and compare to advertised. Am I missing something?
There are so many variables that affect range and consumption that it makes for a really, really lousy indication of the health of your battery. Speed, temperature, terrain, wind, traffic, precipitation, snow, altitude - all of these affect your range and how much juice you use for a trip to greater or lesser degrees. It's pretty much impossible to eliminate all of those factors to tease out whether or not your battery has lost capacity.

In the absence of any hard data from the car, the best you can do is to keep meticulous records and hope that a wealth of data may show a trend line that seems plausible.
 

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Discussion Starter #5
Here is the Spark Energy Used screen. It's very different from the Bolt's. Far more illustrative of use....and degradation.

THis page suggests a 17 kWh battery capacity, but this is higher than what I've been getting of late which is usually 16.1 kWh.

Either way, you can calculate degradation and I don't think the lawyers want you to do the math. Spark's screen is more honest so to speak.
 

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A seemingly easy way would be to measure raw SOC charge % via Torque Pro + OBDII, and keep a log. If the raw # after a 100% charge starts dipping noticeably, that's probably an indication of battery degradation.

From what I've observed, a 100% charge should register a 96.x % raw SOC, though that number can vary slightly. If a 100% charge starts reading raw SOC values more than a few percentage points below 95-96%, that could be a sign the battery is fading.
 

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Here is the Spark Energy Used screen. It's very different from the Bolt's. Far more illustrative of use....and degradation. THis page suggests a 17 kWh battery capacity, but this is higher than what I've been getting of late which is usually 16.1 kWh.
I don't see anything on that page which suggests a 17kWh battery, or indeed anything other than an indication of how much energy was consumed.
 

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Bro1999, my Outlander PHEV had lost more than 30% capacity. When full, raw soc is still reported as 100%. It is calculated as max Ah / current Ah.
 

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So the bolt has this one...

Is that what you are looking for?
I assume you were trying to show a Bolt energy detail screen. I just discovered something VERY interesting. The one shown in this article, from January, shows a screen set up like the one in Boltedown's Spark EV.

https://digitalscientists.com/blog/driving-the-ultimate-user-experience

The one in our Bolt is like this one.

https://electrek.co/2016/09/06/gm-bolt-ev-one-pedal-driving-regenerative-braking/
 

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I assume you were trying to show a Bolt energy detail screen. I just discovered something VERY interesting. The one shown in this article, from January, shows a screen set up like the one in Boltedown's Spark EV.

https://digitalscientists.com/blog/driving-the-ultimate-user-experience

The one in our Bolt is like this one.

https://electrek.co/2016/09/06/gm-bolt-ev-one-pedal-driving-regenerative-braking/
The one in the article should be available to you as well. Press the energy graphic on your infotainment screen and then choose the information option. The arrows allow you to scroll through the info. If you dont have that, I would imagine you need an update.
 

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Discussion Starter #15
OUr Spark was the 2016. Whether my battery is presently 16.8 kWh capacity or 16.1, I've had at least 10% degradation in 18 mos. And 17k miles. More like 15%.

All I'm saying is I wish our degradation could be measured on the Bolt as easily as it is on the Spark.

That said, no oil changes, no transmission oil, no spark plugs, no timing belts, no nothing.

All electrics make sense if you're as maintenance averse as I am.

It's funny tho, when I begin to evangelize electrics, people always say, "What about the battery?".....And....."you can't go very far, right?"

Sigh....
 

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The one in the article should be available to you as well. Press the energy graphic on your infotainment screen and then choose the information option. The arrows allow you to scroll through the info. If you dont have that, I would imagine you need an update.
The arrows allow you to scroll through three different screens...efficiency history, energy use score, and energy detail since last charge. The circular energy detail graph is not like the one shown in the article. Can you select a different one in your Bolt? I went to the home screen, and pushed the edit button. There it shows you that you can lay out your home screen in different ways. Interestingly, the screens they show as examples ALL show a circular energy graph laid out like the one in the Spark EV, but not in my Bolt!
 

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People tend to look at capacity as a constant and not a variable. Capacity (available energy) is affected by temperature and discharge rate. Low temperatures and higher discharge rates both result in less capacity available from the battery.

In addition, the screen info is way too imprecise to accurately figure capacity.
Using the first screen shot as an example, factoring for rounding errors yields a capacity range of 16.21 kWh to 18.04 kWh

19% can be 18.50% to 19.49%
5% can be 4.50% to 5.49%
4.1 kWh can be 4.050 to 4.149

So % used ranges from 23.00% to 24.98%, and capacity used from 4.05 kWh to 4.149 kWh.
 

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Someone needs to make an ODBII tool similar to LeafSpy for the Nissan Leaf. There's a lot more to battery health / performance than simple SOC %. Although with the larger battery and TMS system, it seems likely the Bolt is much less likely to experience significant degradation than the Leaf was.
 

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banksdad said:
The one in the article should be available to you as well. Press the energy graphic on your infotainment screen and then choose the information option. The arrows allow you to scroll through the info...
What software version are you running on your Bolt?
Mine would not at 13.4.0 and will not at 14.4.2 show that screen.
 

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Sean Nelson, take 4.1 and divide by 24%. Equals 17.08kwh
In the Bolt, the portions of circle graph represents the percentage for each type of usage, but the entire circle represents only the amount of energy used since the last charge.

Are you saying that for the Spark's very similar-looking circle graph, the entire circle always represents the full capacity of the battery?
 
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