I revised the above a number of times since posting. If I have missed something. feel free to post.

Kabloona posted an article about sales of used EV's and how some were surprised that high mileage EV's even existed, the assumption being that high miles affected battery life. That got me thinking those with minimal EV experience or knowledge might benefit from some info around this subject with an Equinox slant. But the points apply to all/most EV's I think, whether GM or not.

 

My Volt's battery degradation (5% since 2017 and 91,000 miles) has occurred almost exclusively in the winter. I keep the car plugged in when at home. I suspect cold weather also contributes to battery degradation as well as excessively hot weather.

 

My Volt's battery degradation (5% since 2017 and 91,000 miles) has occurred almost exclusively in the winter. I keep the car plugged in when at home. I suspect cold weather also contributes to battery degradation as well as excessively hot weather.

I'm at about 20% permanent range reduction for my 2011 Volt. I updated the above conclusion to add keeping the car plugged in. Good catch, thanks!

I suspect cold weather also contributes to battery degradation as well as excessively hot weather.

This might be a question of semantics regarding temporary reduced range vs. permanent battery degradation, Obermd. I should have defined "degradation".

It's well known that cold weather will reduce driving range for a variety of reasons. I haven't seen anything that indicates cold weather permanently damages the battery however, Obermd. The range always seems to bounce back in summer. Have you anything showing that cold weather permanently reduces the range from that point on?

 

I'm at about 20% permanent range reduction for my 2011 Volt. I updated the above conclusion to add keeping the car plugged in. Good catch, thanks!



This might be a question of semantics regarding temporary reduced range vs. permanent battery degradation, Obermd. I should have defined "degradation".

It's well known that cold weather will reduce driving range for a variety of reasons. I haven't seen anything that indicates cold weather permanently damages the battery however, Obermd. The range always seems to bounce back in summer. Have you anything showing that cold weather permanently reduces the range from that point on?

I'm using the car's energy screen to determine it's a overall long term drop from 14 to 13.5 usable KWh in my battery. These drops only occur during winter driving and don't recover during summer driving. The actual KWh before switching to gas runs anywhere from 13.2 (if I'm doing 75) to 13.9, but most days at 65 MPH on my commute it's 13.4 or 13.5 KWh before battery depletion.

Still, this is only a 5% reduction in capacity after 7 years and 90+ thousand miles.

 

RE: battery degradation - apologies if someone else mentioned this and I just missed it, but a couple of things:
1) Most EVs will see the largest drop of battery degradation in its first year of operation and then it tends to level off at a lower rate over time
- My 2023 ID.4 (purchased 1st week of December 2022) is at 96% (tested using an OBD dongle looking at maximum content high voltage traction battery compared to standard known usable battery kWh)
2) Many EVs also can get a tiny bit confused at times when giving you estimated ranges on the infotainment screen
- Some vehicles have deep charging cycle resets that help to "reset" the battery management system's knowledge of what's possible. For the ID.4 the test is to go to <10% SOC (better at around 5%) and then charge to above 90% (better at 100%) and then let it sit for about an hour. Obviously, sitting at 100% and discharging to close to 0% is not ideal itself for the battery, but it is actually a known test that some manufacturers suggest to keep the car giving you accurate information. As well, sitting at 90-100% for one hour a few times a year is not detrimental to the battery (leaving it for many hours or charging to 100% often is)
3) needing to replace the battery just after the warranty expires

• I can't remember the article I read, but it was likely from Recurrent Auto but most batteries can likely survive multiple 100s of thousands of miles. There are also some Model S owners that have had their cars for 500,000+ (crazy!) and have had to replace the battery once? twice? and maybe the motors a couple of times as well. But the cost was justified based on the fact that they had it for the life of what would be 5+ cars (if you assume about 10-12,000 miles per year and owning a car for 8-10 years.
• Also, if you really needed to replace the battery after say 200,000 miles (let's call it 16 years), the cost of batteries per kWh will by lower than it is now. So while we're seeing people having to replace batteries at $10-20,000, I wouldn't be surprised if it was closer to the lower end of that spectrum by the time any of us need to do so.

 

1) Most EVs will see the largest drop of battery degradation in its first year of operation and then it tends to level off at a lower rate over time

Degradation: capacity fade and power fade
There are two types of battery degradation: capacity fade and power fade. These are the result of both physical and chemical changes in the battery cell over time.

"The directly observable effects of degradation are capacity fade and power fade. Capacity fade is a reduction in the usable capacity of the cell and power fade is a reduction of the deliverable power of the cell after degradation. These observable effects are the least detailed viewpoint of degradation but are the easiest to measure. As a result, many practical measures of cell degradation are of capacity fade and power fade."

Degradation Over Discharge Cycles (Time)
The number of Discharge Cycles will also affect battery degradation. There's not really anything you can do to decrease the number of cycles other than not driving the car, so don't worry about it. I found this graph showing degradation over time that seems to support accelerated degradation during the first 90 or so discharge cycles, followed by a long plateau period of linear aging, and finally a final non-linear decline:

What's Causing this Behavior?
There are debates as to what's actually causing the changes. The cause of the debates is the difficulting of actually seeing what's going on inside the battery during use.

Indirect Measurement of Battery State of Health and State of Charge
Unfortunately, direct measurement within a cell would require extremely expensive sensors that can also interfere or disrupt the reactions taking place.

And because degradation can be both chemical and physical taking place at the negative electrode, the positive electrode, within the body of the cell, etc., no one test or measurement can capture the battery State of Health (SOH) and State of Charge (SOC).

Your Car's BMS Uses Modeling to Estimate What's Going On
So, predictive modeling is used by your car instead. There are three models: empirical, physical and single particle.

Due to its computational efficiency in terms of speed, memory and numerical convergence, empirical modeling is widely used in the car's Battery Management System (BMS) to predict the SoC and SoH of batteries for vehicle power management control.

This empirical modeling estimates the electrical behavior of your battery using a set of circuit elements, such as resistors and capacitors. The elements in the model may not necessarily have direct relevance to your real battery, but simulates its overall behavior.

Things like a kWh Used display in the infotainment screen is a simplification of this modeling. It's not an actual meter reading so to speak.

Can My Dealer Determine the Degradation Level of My Battery?
Sadly, no. The inability to directly measure all the chemical and physical degradation in your battery is why a dealer can't give you a direct answer on your battery's state of health.

There are apps that can be used to look at cell voltage levels of course and identify cells that are weak or in danger of falling below a threshold. But that's just an indirect way of looking at degradation.



So How Do I Know If My Battery Is Degraded?
Degradation is a given and starts when the battery is assembled. You can get a glimpse of how much your battery has degraded by looking at the total miles you are able to drive on a charge. Of course, many outside variables will confuse the answer. For example, are you driving on the same road, in the same weather, in the same way, with the same tire pressure, the same cabin climate controls, the same time of day? These can all affect the miles you get and muddy the picture. Still it's a relatively easy if imperfect way to get an indirect glimpse of how the battery is doing.

My 2011 Chevy Volt used to get me 45-48 miles when new. Now, 12-1/2 years later, it's delivering 35-38 miles and is often engaging the gas range extender even when the battery has a charge. Though still working, the battery is clearly in the end-of-life saturation phase.

MyGreenVolt Connect app plus an OBD2 module can be used to scan the battery full and empty.to determine if there are bad cells. There are other apps as well.

Here's a Bolt EV owner who posted how he determines the amount of degradation by using as much energy as possible and then comparing the energy used with the reported battery level.
As an example, he would:

1. Start a trip on a full battery with a reset Energy Usage screen.
2. Drive for at least 150 to 200 miles before stopping for the first charge.
3. Record the energy used and the battery percentage displayed.
4. Calculate estimated capacity by dividing kWh used by percent used and multiplying by 100.

He's doing this regularly and keeping meticulous notes.

What Do All the Acronyms, Abbreviations and Terminology Mean?
We have a guide to all the acronyms, abbreviations and terminology here.

Lithium ion battery degradation: what you need to know - Physical Chemistry Chemical Physics (RSC Publishing) DOI:10.1039/D1CP00359C

 

@Steverino, Interesting report out of SLAC and excellent find. What's really odd is my Ego snowblower manual says not to use the batteries if they're significantly below freezing. I wonder if this is why.

 

Yeah, what the hell does a linear accelerator have to do with car batteries? Aren't they supposed to be hunting for quarks and Z bosons and whatnot.....? 🤔

Next Ultium battery update: car powered by anti-matter propulsion system.... 🤣

 

EV owners may have concerns about the longevity of their car's high voltage traction battery. Will the car's battery last 8 years? 10 years? 15? High-mileage EVs were thought to be rare, or at least decommissioned, because of fears of permanent battery degradation.

• What is battery degration?
• Will my Equinox EV suffer battery degradation?
• What happens if it does?
• What factors affect deflation and are there do's and dont's I can use to minimize degradation?

What is battery degradation?
For this thread, battery degradation is defined as a permanent reduction of battery driving range, or damage to battery cells not caused by an accident.

It's not the same as a drop in driving miles caused by speed, such as going say 70 MPH vs. 30 MPH. Or fewer miles caused by turning the cabin heat up to blast furnace in winter, or rolling on under-inflated tires. Those are temporary. Slowing you speed, moderating your climate settings, keeping your tires at proper pressure will restore range.

Instead, we are talking about things that may permanently damage or age your battery. Yes, this will also reduce range, but the range is forever lost.

Will my Equinox EV suffer battery degradation?
Yes, eventually your car battery will degrade (age).

Note: EV's (indeed any type of car) will have reduced winter driving range due to increased use of cabin heating, less road traction, denser air, and the like. More electricity is used for these so less is available for travel distance. That's a seasonal fluctuation rather than a permanent degradation issue.

What Happens If It Does?
As it ages, you'll start seeing less driving range. Eventually, a battery cell or two may become so weak it may cause problems for the entire battery pack, throwing errors or even making the car undriveable.

If the cell is bad enough, the battery module that contains the weak/bad cell will need to be replaced. The good news is the Equinox EV uses the Ultium battery platform. It was designed to allow the battery pack to be serviced and for modules to be replaced. This is not the case for all EV's. Some car makers require the entire, expensive battery pack be replaced.

Based on previous GM EV's, the Equinox EV should not experience any battery issues within it's 8 year warranty, and very likely many years beyond (my Volt is over 12-1/2 years old as of this writing, and I am not alone).

What Factors Affect Degradation? What Can I Do To Minimize it?
There are a number of factors you should be aware of that can affect an Equinox EV's battery life:

1. Advanced Age
2. 100%l Charge, 100% Discharge
3. Extreme Heat
4. Extreme Cold
5. Aggressive DC Fast Charging

Age vs. Battery Degradation What About Miles?
The takeaway: Don't worry about the car miles as related to battery degradation. Do be aware that battery age does have an affect. So don't avoid putting miles on the car thinking that the battery will last longer.

Based on the last decade of EV experience, 200,000 and 300,000 miles are not a big factor in battery degradation.

Anecdotally, battery degradation is more age-based than miles driven. Even AA battery packaging has a "best use by" date. Volt owners start to see some degradation after about 10 years regardless of odometer miles.

Full Charge/Discharge vs. Battery Degradation
Another factor can be 100% discharges and 100% charges. Lithium ion batteries don't like being fully discharged, and to some extent, being fully charged.

The Volt for example was engineered to avoid both extremes by keeping a portion of the battery essentially blocked off as a buffer at the high and low ends. The buffer's are not normally accessible to the driver and act to as a protrective cushion against 100% discharge or 100% charge.

My Bolt doesn't have this safety net, but it does have a selectable setting called Hilltop Reserve that stops the charging at ~90% preventing a 100% charge (you can turn it off if planning a long trip and want 100% charge). Hilltop Reserve is used by those who say, live on a hill. In the morning, the car's regeneration can be used to top of the battery as the car goes downhill. Otherwise, a full battery would waste the free gravity-assist charge opportunity. And of course I never run the battery down to 0% charge.

The Blazer EV owner's manual addresses this as well:
"GM recommends the following:
. Unless your drive requires a full charge, charge the high voltage battery to 80% or less.
. Avoid allowing the high voltage battery to fall below 20% charged, if possible.

Newer Bolts have Hilltop Reserve replaced by a user selectable charge limit. Now you can set exactly the max charge you want by 5% increments via a Target Charge Level tab on the Charging screen.

The Blazer EV has something similar. I expect the Equinox EV will as well.

View attachment 1592

The newer Bolts can use the location-based charging to make the charge setting "stick" to what you want it to be when charging at Home or away. The Blazer EV has this capability, so I expect theEquinox EV will have it.

Extreme Heat vs. Battery Degradation
Whenever possible, while parked keep the car plugged in so the car can keep the battery cool in very hot weather. The car can then keep the battery in its preferred temperature range. Being too hot can shorten battery life.

Because batteries can be degraded by heat, most EV's have active liquid Thermal Management Systems. The Equinox EV (and all Ultium battery platforms) have active liquid TMS.

Extreme Cold vs. Battery Degradation
Whenever possible, while parked keep the car plugged in so the car can keep the battery warm in very cold weather. A frozen battery may cause degradation, being too cold can shorten battery life.

Most EV's have active liquid Thermal Management Systems. The Equinox EV (and all Ultium battery platforms) have active liquid TMS. The TMS will keep the battery in its preferred temperature range.

DC Fast Charging vs. Battery Degradation
The car controls DC fast charging, so there's not much you need to do or worry about.

While there is some concern that frequent, heavy use of DC fast charging has potential to degrade the battery, GM has said the Ultium batteries can take it.

So why the DC fast charging concern? The very high heat generated during DC fast charging has the potential to "cook" a battery.

This is why the car's active liquid cooling Thermal Management System (TMS) is very important. It keeps the battery cool by drawing away the heat. The Equinox EV has a great TMS and will also limit the rate the car is charged at. For good or bad, GM is very conservative on this.

Part of the maximum charge rate is also dependent on the voltage of the car. EV's like the Hummer EV and Silverado EV based on a 800V system can sustain higher charge rates than the Equinox EV.

NOTE: The AC charging you do at home doesn't create the heat that DC charging does, and the car's TMS will handle whatever comes its way. Don't worry about home charging from a heat degradation standpoint. While plugged in, you may hear fan or pump noises even if the car is not on. This is normal, it's the TMS doing its job.

Conclusion
1) Battery charging is something you have control over. How you charge the car can affect battery longevity. Avoid 100% discharge, charge to 80% max as standard practice unless you have a big trip coming. It's safe and OK to charge to 100%, but if you want to maximize battery life, minimize 100% charges when possible.

2) Whenever possible, keep the car plugged in when not in use. This helps the TMS keep the battery in a Goldilocks temperature range during extreme temperatures conditions.

I know this is an older post, but I was wondering if there is also a difference in using Level 1/2/3 charging in affecting the battery life? Or does home vs. public charging not matter, as long as you stick between 20-80%?

 

It seems the heat generated by fast charging may cause a problem with some batteries. Ultium is supposed to handle it. There are some great posts that go into in more detail in the forum.

 

It’s unclear based on current data. Many suggest that DC fast charging the majority of the time has a significant negative effect on battery longevity, but some recent studies suggest it may not have as great of an effect as we previously thought. In addition, theoretically, charging at any level but from low to high percentages can take a toll on longevity (i.e. charging from 20-80% every time) and that charging at smaller intervals (i.e. 30-50%) and keeping the battery closer to 50% most of the time and only charging to larger percentages (i.e. 80-100%) is safer. As well not going below 20% or over 80% for any significant period of time. With all that said, I think overthinking this too much is not worth the worry as we really don’t have enough data suggest the perfect way to sustain the battery. Simply charge over 80% only when absolutely needed for a road trip, try not to go under 10% if you don’t have to, and otherwise just use what you need regardless of charging speed based on your use case.

 

Simply charge over 80% only when absolutely needed for a road trip, try not to go under 10% if you don’t have to, and otherwise just use what you need regardless of charging speed based on your use case.

GM has said DCFC (Level 3) won't degrade the Ultium batteries, perhaps because GM limits the charging rate which is a bit slower than some other manufacturers.

As far as Level 1 (120V) and Level 2 (240V) charging at home, no degradation issues with either one. L2 may be slightly more efficient (less line loss) by a hair.

Regarding avoiding charges to 100% and (almost) full discharges, I think that's prudent advice CTA. That's basically how the Chevy Volt managed the battery behind the scenes.

If it were a gas car, we'd be saying don't pump gas until it's gushing out the fill pipe, don't drive on an almost empty tank.

 

I don’t think DC fast charging won’t degrade the battery. That seems like too bold of a statement from GM. It’s still an NMC battery. I think it’s just not to the point that you should over worry about DCFC:AC ratio for the life of the vehicle

 

I don’t think DC fast charging won’t degrade the battery.

Some studies suggest almost no difference in degradation between those who almost always with DCFC and those who rarely use DCFC. But the study was on Teslas. The assumption is the results would apply to other cars but it's a question mark.

The biggest issue with DCFC is not preconditioning beforehand. In extreme cold or heat that can both add degradation and affect charging times.

too bold of a statement from GM

Bold indeed, CTA.

"But Tim Grewe, GM's global electrification and battery systems director, makes some bold claims for the Ultium pack. He says no amount of DC fast-charging will degrade its capacity, and unlike Tesla and others, GM will not suggest the pack be charged to less than 100 percent during normal daily use. He credits the breakthrough to the careful development of the chemistry, including the addition of aluminum into the cell. Grewe also promises that the Ultium pack "will last longer than the Bolt EV's," which he says is making it to between 150,000 and 250,000 miles in the real world, comfortably past its 100,000-mile warranty."

it’s just not to the point that you should over worry about DCFC:AC ratio for the life of the vehicle

Agreed. Just drive it and enjoy.

 

Because I am getting the car first and then determining my level 2 installation at home and the process required, I will have a mix of level 1 and public charging. I think my goal is to plug in each night at level 1, stay as close to 80% as possible, but to use public charging when it will inevitably reach 20 or 30%. I drive around 80 miles a day (currently), so level 1 is just a little too slow.

Based on what the level 1 Chevy charger says on their website (1-4 miles an hour), I'll probably be able to get between 12-48 miles added a night. So eventually, it'll catch up to me and I'll have to top off at a public charger. I will probably have to visit a public charger once a week, twice max.

There is one near my work that is an EVGo station, so I was thinking of having a monthly account so I can reserve a charger time slot and use my Chevy app to precondition the battery (can the app do that?) before I leave work.

The good news is that I am a teacher, so come late June, I won't have to worry about public charging! This is just a temporary for a couple months. Then I can really focus on getting that level 2 ready.

 

Because I am getting the car first and then determining my level 2 installation at home and the process required, I will have a mix of level 1 and public charging. I think my goal is to plug in each night at level 1, stay as close to 80% as possible, but to use public charging when it will inevitably reach 20 or 30%. I drive around 80 miles a day (currently), so level 1 is just a little too slow.

Based on what the level 1 Chevy charger says on their website (1-4 miles an hour), I'll probably be able to get between 12-48 miles added a night. So eventually, it'll catch up to me and I'll have to top off at a public charger. I will probably have to visit a public charger once a week, twice max.

There is one near my work that is an EVGo station, so I was thinking of having a monthly account so I can reserve a charger time slot and use my Chevy app to precondition the battery (can the app do that?) before I leave work.

The good news is that I am a teacher, so come late June, I won't have to worry about public charging! This is just a temporary for a couple months. Then I can really focus on getting that level 2 ready.

look into your local utility company. Mine paid for $500 toward the charger and $500 toward the installation and through federal taxes got about $200 back that way. I’ve also gotten $250 back for not charging during peak periods when they tell me. Also, while I do have a 48 amp charger, it’s not necessary. 32 kW is just fine enough but also there are great smart chargers for roughly $300 (Emporia) (just get a quality one when you do). Hardwired is better but you could get an electrician to properly install a NEMA 14-50 outlet and make sure you have a dedicated line. Installing anything that doesn’t require a dedicated 60 amp line requires less copper and therefore a little cheaper. Depending on where your box is, it could be pretty reasonable to install

 

"But Tim Grewe, GM's global electrification and battery systems director, makes some bold claims for the Ultium pack. He says no amount of DC fast-charging will degrade its capacity, and unlike Tesla and others, GM will not suggest the pack be charged to less than 100 percent during normal daily use. He credits the breakthrough to the careful development of the chemistry, including the addition of aluminum into the cell. Grewe also promises that the Ultium pack "will last longer than the Bolt EV's," which he says is making it to between 150,000 and 250,000 miles in the real world, comfortably past its 100,000-mile warranty."

Not according to the owners manual:

The default charge level is 80% when plugged in to protect battery life.

 

Yes, it would be great to get Tim Grewe's comment on that based on his previous statement.

 

EV owners may have concerns about the longevity of their car's high voltage traction battery. Will the car's battery last 8 years? 10 years? 15? High-mileage EVs were thought to be rare, or at least decommissioned, because of fears of permanent battery degradation.

• What is battery degration?
• Will my Equinox EV suffer battery degradation?
• What happens if it does?
• What factors affect deflation and are there do's and dont's I can use to minimize degradation?

What is battery degradation?
For this thread, battery degradation is defined as a permanent reduction of battery driving range, or damage to battery cells not caused by an accident.

It's not the same as a drop in driving miles caused by speed, such as going say 70 MPH vs. 30 MPH. Or fewer miles caused by turning the cabin heat up to blast furnace in winter, or rolling on under-inflated tires. Those are temporary. Slowing you speed, moderating your climate settings, keeping your tires at proper pressure will restore range.

Instead, we are talking about things that may permanently damage or age your battery. Yes, this will also reduce range, but the range is forever lost.

Will my Equinox EV suffer battery degradation?
Yes, eventually your car battery will degrade (age).

Note: EV's (indeed any type of car) will have reduced winter driving range due to increased use of cabin heating, less road traction, denser air, and the like. More electricity is used for these so less is available for travel distance. That's a seasonal fluctuation rather than a permanent degradation issue.

What Happens If It Does?
As it ages, you'll start seeing less driving range. Eventually, a battery cell or two may become so weak it may cause problems for the entire battery pack, throwing errors or even making the car undriveable.

If the cell is bad enough, the battery module that contains the weak/bad cell will need to be replaced. The good news is the Equinox EV uses the Ultium battery platform. It was designed to allow the battery pack to be serviced and for modules to be replaced. This is not the case for all EV's. Some car makers require the entire, expensive battery pack be replaced.

Based on previous GM EV's, the Equinox EV should not experience any battery issues within it's 8 year warranty, and very likely many years beyond (my Volt is over 12-1/2 years old as of this writing, and I am not alone).

What Factors Affect Degradation? What Can I Do To Minimize it?
There are a number of factors you should be aware of that can affect an Equinox EV's battery life:

1. Advanced Age
2. 100%l Charge, 100% Discharge
3. Extreme Heat
4. Extreme Cold
5. Aggressive DC Fast Charging

Age vs. Battery Degradation What About Miles?
The takeaway: Don't worry about the car miles as related to battery degradation. Do be aware that battery age does have an affect. So don't avoid putting miles on the car thinking that the battery will last longer.

Based on the last decade of EV experience, 200,000 and 300,000 miles are not a big factor in battery degradation.

Anecdotally, battery degradation is more age-based than miles driven. Even AA battery packaging has a "best use by" date. Volt owners start to see some degradation after about 10 years regardless of odometer miles.

Full Charge/Discharge vs. Battery Degradation
Another factor can be 100% discharges and 100% charges. Lithium ion batteries don't like being fully discharged, and to some extent, being fully charged.

The Volt for example was engineered to avoid both extremes by keeping a portion of the battery essentially blocked off as a buffer at the high and low ends. The buffer's are not normally accessible to the driver and act to as a protrective cushion against 100% discharge or 100% charge.

My Bolt doesn't have this safety net, but it does have a selectable setting called Hilltop Reserve that stops the charging at ~90% preventing a 100% charge (you can turn it off if planning a long trip and want 100% charge). Hilltop Reserve is used by those who say, live on a hill. In the morning, the car's regeneration can be used to top of the battery as the car goes downhill. Otherwise, a full battery would waste the free gravity-assist charge opportunity. And of course I never run the battery down to 0% charge.

The Blazer EV owner's manual addresses this as well:
"GM recommends the following:
. Unless your drive requires a full charge, charge the high voltage battery to 80% or less.
. Avoid allowing the high voltage battery to fall below 20% charged, if possible.

Newer Bolts have Hilltop Reserve replaced by a user selectable charge limit. Now you can set exactly the max charge you want by 5% increments via a Target Charge Level tab on the Charging screen.

The Equinox EV has a charging settings screen that enable you to set a maximum charge percentage. 80% is recommended for daily use. 1200% if taking a long trip.

View attachment 1592

The newer Bolts can use the location-based charging to make the charge setting "stick" to what you want it to be when charging at Home or away. The Blazer EV has this capability, so I expect theEquinox EV will have it.

Extreme Heat vs. Battery Degradation
Whenever possible, while parked keep the car plugged in so the car can keep the battery cool in very hot weather. The car can then keep the battery in its preferred temperature range. Being too hot can shorten battery life.

Because batteries can be degraded by heat, most EV's have active liquid Thermal Management Systems. The Equinox EV (and all Ultium battery platforms) have active liquid TMS.

Extreme Cold vs. Battery Degradation
Whenever possible, while parked keep the car plugged in so the car can keep the battery warm in very cold weather. A frozen battery may cause degradation, being too cold can shorten battery life.

Most EV's have active liquid Thermal Management Systems. The Equinox EV (and all Ultium battery platforms) have active liquid TMS. The TMS will keep the battery in its preferred temperature range.

DC Fast Charging vs. Battery Degradation
The car controls DC fast charging, so there's not much you need to do or worry about.

While there is some concern that frequent, heavy use of DC fast charging has potential to degrade the battery, GM has said the Ultium batteries can take it.

So why the DC fast charging concern? The very high heat generated during DC fast charging has the potential to "cook" a battery.

This is why the car's active liquid cooling Thermal Management System (TMS) is very important. It keeps the battery cool by drawing away the heat. The Equinox EV has a great TMS and will also limit the rate the car is charged at. For good or bad, GM is very conservative on this.

Part of the maximum charge rate is also dependent on the voltage of the car. EV's like the Hummer EV and Silverado EV based on a 800V system can sustain higher charge rates than the Equinox EV.

NOTE: The AC charging you do at home doesn't create the heat that DC charging does, and the car's TMS will handle whatever comes its way. Don't worry about home charging from a heat degradation standpoint. While plugged in, you may hear fan or pump noises even if the car is not on. This is normal, it's the TMS doing its job.

Conclusion
1) Battery charging is something you have control over. How you charge the car can affect battery longevity. Avoid 100% discharge, charge to 80% max as standard practice unless you have a big trip coming. It's safe and OK to charge to 100%, but if you want to maximize battery life, minimize 100% charges when possible.

2) Whenever possible, keep the car plugged in when not in use. This helps the TMS keep the battery in a Goldilocks temperature range during extreme temperatures conditions.

Thanks, I'm still reading...

 

Tesla's numbers show that frequent DC fast charging doesn't have an impact on overall battery degradation.

 

I would say, as big of an impact as expected.
Any charging has an impact, it’s just been a gloom and doom expectation for how quickly fast charging would degrade a battery that so far hasn’t materialized.

 

Because there is not definitive proof or warranty that all newer battery packs will go over 200,000 miles, a lot of people question the financial advantage of buying an EV over an ICE vehicle. I guess we have to have some faith in what we are told by other long term owners many that drive Teslas

 

Plenty of Bolt(well now most got reset) and Volt owners who've gone well over 100K miles on their batteries.

 

Appears as though the EQ-EV charging curve is deliberately dialed-back, possibly to protect battery life.....🤔

 

K, I was thinking the same thing.

 

On a Vlog published yesterday, Tom Moloughney promised to run a charging test on the EQ EV as soon as possible, but he also mentioned that GM were "pushing back" on his testing protocol. Apparently they weren't too happy when he ran a Bolt down to zero charge and got stranded on a highway during one of his 70 mph range tests.... 😆

 

Apparently they weren't too happy when he ran a Bolt down to zero charge and got stranded

They may be thinking of a YouTube headline picked up on news sites: "Chevy Bolt EV runs out of power, leaves driver stranded!!"

 

No, that's far to big for the EQEVs battery and you also have to account for regen.

 

Hmm. Maybe the best way to do it is go out to a stretch of interstate, reset the Trip, log the starting SOC, and drive for a significant distance? That should avoid/minimize the impact of Regen.

 

Flat road, engage Cruise Control, don't use brakes.

 

Assuming the battery does degrade rather quickly at the saturation stage, when would that occur during the life of the vehicle?
Taking a stab at it, I came up with this. Let’s assume the vehicle is driven 10,000 miles/year. Let’s also assume 50% battery capacity charging such as going from 25% to 75%. 50% battery capacity is roughly 150 miles. That would be 66 charge cycles per year. The graph posted earlier shows saturation stage starting around 600 charges. That would be 9 years (90,000 miles) before saturation begins. This is similar to the battery warranty of 8 years/100,000 miles.
I have maintained my ICE vehicles to go 150k - 200k miles. I was hoping to do the same with my EV’s or until I can’t drive anymore. I could always replace the battery which should be much cheaper in 10 years.

 

Several EVs have gone well over 100K miles without concerning degradation. Then it all depends on how you use the vehicle and charge it.

 

Plus, EVs degradation largely seems connected with age, and even single cells losing capacity and then being pushed beyond what they can do, repeatedly, in the process of dealing with the capacity of the rest of the pack in normal driving conditions. That "It's just one cell" factor is why I'm so committed to Ultium's promise replicable battery modules. Spending $2-3k for a new module after warranty because 1) modules are still available because they're still being produced for new cars and 2) the pack was designed to be opened and modules replaced is WAY more appealing that being asked to spend $25-35k for a refurbished pack.

 

Typo: 1200% if taking a long trip.

 

I have maintained my ICE vehicles to go 150k - 200k miles

After all is said and done, calendar aging seems more important than miles when it comes to battery degradation, Mike.

Typo: 1200% if taking a long trip.

Corrected, thanks DrM !

 

When you refer to calendar aging, does it mean the day to day use of a vehicle and thus other parts wear out?

 

Each day the battery gets older and degrades whether you use it or not, Mike. A 10 year old battery sitting on a shelf unused will have degraded with time.

Miles driven isrelated to degradation in regard to how often (number of cycles) the battery will be recharged. 0-100% charges are considered one cycle. Also, heat. Batteries stored in a very hot warehouse for many years will degrade more than those kept cool. This is one reason why the car has a cooling system and it's good practice to keep the car plugged in so it can cool itself if needed.

This is covered in more details in post #1.