How much will my battery degrade after two years of charging to 100% almost every night?

[SparkE]

...how do you suggest I take that measurement now?

I described the method in my first post in this thread.

Yes, I recall, but your method requires that I have a comparison measurement to when my car was new, which I never took.

Hint: skip the 'comparison' portion - you simply measure capacity, not capacity loss.

To get an idea of capacity loss, you'd have to look at the state of charge of the battery at the end of the drive, use the kWh to extrapolate the total battery capacity, and then compare that to the same metric from when the car was new.

For example, if you had a 5% charge left at the end of that trip, and assuming that you started with 100% charge, that means that the 55.5kWh you used for the trip represents about 95% of your battery (100% - 5%). That, in turn, would tell you that the battery has a capacity of approximately 58.4kWh (55.5 / 0.95). If you could compare THAT number to a similar measurement taken when the car was new THEN you'd have some indication of capacity loss.

In practice, the capacity figure you get by doing this bounces around somewhat, so you'd have to take the average of several readings to get a sense of what's happening with the battery.

 

[BoltEV]

Next time I will settle the debate by using the My Chevrolet app at the end of the drive to tell me the remaining capacity.

Yes, thank you.

I already acknowledged my mistake earlier and what I should have done to compute remaining capacity (other than driving until I run out of juice).

If the app reports X%, then, as Sean notes, the amount of full capacity would be the amount of Energy Used, divided by 100% minus X% (in decimal form).

I suppose it would be interesting to compute it both ways and compare!

 

[SeanNelson]

...how do you suggest I take that measurement now?

I described the method in my first post in this thread.

Yes, I recall, but your method requires that I have a comparison measurement to when my car was new, which I never took.

You asked how you could determine your battery capacity now. That's how to do it. There's no way to know what it was when the car was new if you didn't measure it then. The reason to measure the capacity now is so that you'll have a baseline against which to judge any future capacity loss.

 

[cranial1963]

Thank you Sean.
So you are not convinced that we all have the same 60KWh capacity when new?

I have seen posted Torque Pro logs from other people, that they had taken when the Bolt was brand new, and a few were over 60 kWh, most were in the 57-59.x kWh range. It apparently does vary, by up to several percentage points.

I would agree, there are definite variances.
To me the simplest way to measure battery capacity/degradation is with an OBD II reader.
I use the LELink OBD-II Plugin with the OBD Fusion app and log measurements here and there.
You can see my capacity varied +/- about 1%-2% over the last 4-5 months:
01/03/2019: Battery Capacity: 59.26
11/25/2018: Battery Capacity: 59.22
11/14/2018: Battery Capacity: 58.83
11/03/2018: Battery Capacity: 58.52
10/29/2018: Battery Capacity: 58.93
10/18/2018: Battery Capacity: 57.92
10/16/2018: Battery Capacity: 57.96
10/06/2018: Battery Capacity: 58.69
10/03/2018: Battery Capacity: 58.87
09/26/2018: Battery Capacity: 58.49
09/16/2018: Battery Capacity: 58.66
08/29/2018: Battery Capacity: 59.78
08/26/2018: Battery Capacity: 59.85

In any case, having an OBD reader and app makes checking your battery's capacity a quick and easy thing to do.

 

[paulgipe]

I posted an article on our experience yesterday to my web site. See Tracking Chevy Bolt EV Battery Capacity.

Here's the gist on our Bolt after 14 months and 11,000 miles, mostly charged to 100%.

During the past five months our capacity has varied from 61.1 kWh, when I began recording the data from Torque Pro, to a low of 59.6 prior to a battery software update.

For my use, capacity has hovered around 60 kWh--more or less--and that's what I need to know for the purpose of route-planning. So far, there's been no discernible battery degradation sufficient to reduce the advertised range of our Chevy Bolt.

Paul

 

[theothertom]

I posted an article on our experience yesterday to my web site. See Tracking Chevy Bolt EV Battery Capacity.

Here's the gist on our Bolt after 14 months and 11,000 miles, mostly charged to 100%.

During the past five months our capacity has varied from 61.1 kWh, when I began recording the data from Torque Pro, to a low of 59.6 prior to a battery software update.

For my use, capacity has hovered around 60 kWh--more or less--and that's what I need to know for the purpose of route-planning. So far, there's been no discernible battery degradation sufficient to reduce the advertised range of our Chevy Bolt.

Paul

Looks like maybe there's 26 DCFC over the 14 month period? If so, I assume there were many L2 charges during that time. Mostly at 100%?

 

[BoltEV]

I now realize that regeneration corrupts my abilty to accurately measure battery capacity through driving.

Is there any way to turn it off?

 

[SeanNelson]

I now realize that regeneration corrupts my abilty to accurately measure battery capacity through driving.

Is there any way to turn it off?

Regen while driving doesn't affect capacity, it only affects range. Range and capacity are two different things. If you have an ICE vehicle with a 10-gallon gas tank, that 10 gallons on its own doesn't tell you anything about how far you're going to be able to drive, and adding 2 gallons to the tank partway through your drive doesn't change its capacity.

The "Energy information" screen in the Bolt tracks how much energy you've used, and it also tracks how much energy regen has put back into the battery. The result is the net energy usage. So if you've driven far enough that your battery level has dropped by 70% (for example, you charged to 88% in hilltop mode and drove until the battery only had 18% charge left) and in that time your net energy usage was 40kWh (which may include 45kWh of power and 5kWh of regen, (or not!)), then that indicates that your battery capacity is (very approximately) 40kWh/60% = about 57kWh.

 

[BoltEV]

That answer begs the question, Sean:

I was discussing the possibility of driving until my battery ran out of juice and using the Energy Used gauge to tell me battery capacity.

However, regeneration will interfere with that measurement, so I was wondering if there is a way to turn regeneration completely off?

 

[SeanNelson]

I was discussing the possibility of driving until my battery ran out of juice and using the Energy Used gauge to tell me battery capacity.

However, regeneration will interfere with that measurement, so I was wondering if there is a way to turn regeneration completely off?

Regen won't affect the overall measurement, unless the car has some sort of bias in that it erroneously measures 1kWh of regen put into the battery differently than 1kWh of energy used for propulsion. Nobody has ever suggested that this would be an issue.

The reason that regen won't affect the measurement is is because because the "energy used" reading includes the regen energy put back into the battery. Let's say that you drive up to a mountain pass and the Bolt tells you that you've used 10kWh of energy. Then you drive down the other side - as regen puts energy back into the battery the amount of "energy used" will go down - it might drop to, say, 5kWh used. Now you continue to drive along level ground using another 55kWh until the car runs out of juice . At the end of the run, the gauge would show 60kWh used: 10 - 5 + 55. Therefore, the battery capacity when you started was 60kWh. This assumes that you filled the battery, which resets the "energy used" reading to zero, before you started.

The only complication in this is if you recharge the car partway through the run by plugging it in. Unlike regen, charging does not subtract energy being put into the battery, all it does is reset the reading to zero if the charge completes.

Of course the car's measurement isn't 100% accurate, and the more regen you use the more the small inaccuracies might add up. But for a typical drive where the energy being regenerated back into the battery is a pretty small percentage of the battery's capacity I wouldn't expect it to be significant. Other factors such as temperature, driving style, individual cell variances, etc. are probably just as big a source of errors.

 

[BoltEV]

The reason that regen won't affect the measurement is is because because the "energy used" reading includes the regen energy put back into the battery. Let's say that you drive up to a mountain pass and the Bolt tells you that you've used 10kWh of energy. Then you drive down the other side - as regen puts energy back into the battery the amount of "energy used" will go down - it might drop to, say, 5kWh used. Now you continue to drive along level ground using another 55kWh until the car runs out of juice . At the end of the run, the gauge would show 60kWh used: 10 - 5 + 55. Therefore, the battery capacity when you started was 60kWh. This assumes that you filled the battery, which resets the "energy used" reading to zero, before you started.

I see your point, Sean, thank you:

So long as the Energy Used gauge is accurately measuring how much energy is being put back into the battery on the downhill, which I assume it does, then, yes, Energy Used to the point of running out of electricity will tell me the capacity of my battery!

The Regeneration just adds to my mileage range; not the capacity.

 

[SparkE]

If one would like to monitor charging, battery capacity, etc. more closely, I'd suggest one might want to look into buying the 'Torque Pro' smartphone app (if you have android), and a wireless OBD2 dongle (which plugs into the car's diagnostic port).

You can get A LOT of info - including battery capacity, individual battery pack voltages, current charging data (such as AC or DC amps or volts) and a bunch of other stuff - using that app. (It even tells you "SoC the car displays" *as well as* " this is the real SoC of the battery pack".)

I can be a cheap basturd {sic}, however the app is only $5 (and IMO worth that simply for the fun factor). I ended up buying a high-end OBD2 reader, but there are ones out there for not much money at all.

Edit: oh, and it isn't Bolt specific, you can use the same app & OBD2 reader on other vehicles, even ICE vehicles (well, if the dongle is compat with the other car, and if there is a 'extension pack' that identifies the electronic IDs and what they mean for that vehicle).

 

[BoltEV]

Let us know when the app works in Apple's iOS.

 

[GetOffYourGas]

Let us know when the app works in Apple's iOS.

I assume you are talking about the Torque Pro app. It's going to be a long wait.

 

[BoltEV]

Let us know when the app works in Apple's iOS.

I assume you are talking about the Torque Pro app. It's going to be a long wait.

How about using Web Viewer in Chrome on my MacBook Pro?

 

[GetOffYourGas]

I've never tried a MacBook Pro since that's a much less portable solution. If you have the reader, give it a try!

 

[BoltEV]

I've never tried a MacBook Pro since that's a much less portable solution. If you have the reader, give it a try!

Less portable, but according to you I have a long wait for an iOS app.

 

[SparkE]

I've never tried a MacBook Pro since that's a much less portable solution. If you have the reader, give it a try!

Less portable, but according to you I have a long wait for an iOS app.

Torque Pro is an android app. There *are* existing iOS apps for reading OBD2 codes. Engine Link has been recommended, for example (I have never used it).

 

[jdunmyer]

Leaf drivers who wanted to use an Android app were advised to buy a cheap Android smart phone or tablet at WalMart or wherever. Activation was not necessary, I'd think this app would be the same.

 

[BoltEV]

Leaf drivers who wanted to use an Android app were advised to buy a cheap Android smart phone or tablet at WalMart or wherever. Activation was not necessary, I'd think this app would be the same.

One line of thought says I should buy a 2nd iPhone to keep in the car so that Navigation is always available to me when driving the car without having the inconvenience of first plugging in my iPhone as I enter the vehicle (or having to dig into my pocket tied down by a seatbelt and then plug it in) and then remembering to unplug it as I exit the vehicle (or wondering where my iPhone is and then having to go back to the garage to retrieve it).

Now you suggest that I get an android! hahahaha

If I can still drive 250+ miles between charges while still charging to 100% most every night, I am happy without any device convincing me that I am happy!