Unless you need the range, I would set the charge to whatever you need on a regular basis. The closer to 50% to 60% is better long term for the battery.

 

Thanks for all the post guys here's the more specific information.. I drive 3 days a week about 180 mi a day on the highway to deliver auto parts and I've been doing 100% when I get back home after those 180 mi I still have a good 100 left, depending on wind, mostly because I don't do one pedal driving doing 70 mph on the freeway.. of that 180 miles there's about 25 mi where I do one pedal drive and get to work and back home from work.. I could still do up to 90% and be okay doing the 175 to 180 per day that might be better for battery degradation and the long run right?

Thanks for the reply I drive 185 mi per day on the highway 70 mi an hour of that 185 mi about 25 is in town at 35 mph so if I do 90% I'll still have 74 miles left at the end of that run if I do 85% I'll have 61 mi left according to calculations.

 

The response needs some clarification. Using AC Level 1 (120 VAC) (slow) charging, very little battery degradation is created, even when charging to 100% SoC. When using AC level 2 (240 VAC) charging, the only damage is pushing those electrons in for the last 5-10 %. Here, charging to 90% as a routine is the best, but charging to 100% for trips is very acceptable. Using DC Level 2 (DC Level 1 is not found in the US to my knowledge) {DCFC}, charging to 100 % is not good for the battery and charging above 80% is usually not time-efficient. This too, varies, since DC max power rates from 24 kW to 350 kW are all classified DC Level 2 and termed DCFC. Yes, 24 kW is > 19.2 kW (AC max), but calling it DCFC is not useful and may be mis-leading. Should we term all DC charging at 50 kW and below DCSC and reserve that DCFC term for charging above 50 kW? Just my humble opinion.

 

If nothing else, you might want to routinely leave a little bit of room to allow the regenerative braking to work consistently from the start. Say charge to 80-90%. Otherwise initially one-pedal drive or the paddle will be less effective.

 

I charge mine to 100% everyday for work as I work a good distance away from home. I tend to believe DCFC does more for degradation than slow charging, or even level 2 charging it to 100%. Only time will tell.

 

I was just reading a thesis on lithium battery degradation:

A study of the factors that affect lithium ion battery degradation

mospace.umsystem.edu

.

It's on 18650 cells but the principles are applicable. This testing graph charged degradation vs starting SOC and depth of discharge:

Note that the 85-25 in green is better than the 100-40 in red even though both expend the same amount of energy. In short shallower discharges from lower starting SOC is better in the long run.

But the paper does note that calendar time is still the largest driver of degradation whether or not the battery is used or not. Simply put they get old because of time regardless of other factors.

Finally understand that with EVs, 100% is never actually 100% in terms of the battery. No EV actually charges cells to 4.2V.

ga2500ev

 

I was just reading a thesis on lithium battery degradation:


Note that the 85-25 in green is better than the 100-40 in red even though both expend the same amount of energy. In short shallower discharges from lower starting SOC is better in the long run.

But the paper does note that calendar time is still the largest driver of degradation whether or not the battery is used or not. Simply put they get old because of time regardless of other factors.

Finally understand that with EVs, 100% is never actually 100% in terms of the battery. No EV actually charges cells to 4.2V.

ga2500ev

I have poured over those charts in the past, and have developed charging habits for extending the life of my car's battery, and my cell phone battery as well. My personal car charging habits puts me in-between the yellow and purple lines on the graph.

Let me add one thing to your good points: most people may not be aware of this, the test that companies do in laboratories are rapid fire tests in which there is little "rest" periods in-between cycles. Batteries expand and contract as they charge and discharge. This expanding and contracting causes microscopic damage to the battery. The expanding/contracting is not immediate and happens over a short bit of time. I believe this is why it does not harm the battery much to charge to 100% and immediately drive off.

All that to say this: the chart, while good for seeing what performance a battery has or for comparing different chemistries, does not translate into real world driving settings. In other words, if I follow the charging habit shown for the yellow on the graph, while I will see significantly better battery health than someone charging to 100% and draining to 20%, I will not have 5,000 cycles with a 93% SOH.

Edit: I did some reading of the research paper about batteries and found out part of my statement is wrong. I crossed out that part. The degradation at a high state of charge is due to another process. Thanks to those who have posted info for us to read up on!

 

Safe? Yes.

But, if you don't need it, don't charge to and keep at high SoC for no reason. Agree with post 2. Charge to 100% when you need it but don't keep it there.

I've had to write what's at One Pedal braking acting up. Bolt Engineer to the rescue? and One Pedal braking acting up. Bolt Engineer to the rescue? + the posts I've linked to over and over here and other forums I'm on.

Leaving it at 100% or high SoC for extended periods of time, even via L1 charging is not good from a degradation POV.

 

Just drive your car and enjoy it. See this Discussion with GM's chief battery engineer'(Andy Oury). Other than don't overdo DC Fast Charging, and minimize full top to full empty, the engineers have desiged the car so you don't need to worry about it. Too much outdated vodoo continues to be promoted on here. Plug into your home level 2 / 240V outlet and don't worry about it.

 

Too much outdated vodoo continues to be promoted on here. Plug into your home level 2 / 240V outlet and don't worry about it.

It's not "outdated" voodoo. Did you see my posts that I linked to in post 7 along with Hilltop reserve? and What % Should I Charge To?

Please point us to studies that say that non-LFP (since Bolt doesn't use LFP) li-ion batteries like being at high state of charge, esp. for extended periods of time. Seems like those who say it doesn't matter are just trying to comfort themselves. Non-LFP li-ion batteries aren't like lead-acid batteries which do like being full.

Remember that Bolt's battery warranty allows for up to 40% capacity loss before it could be considered defective.

OP, for your case, since you don't seem to need 100%, yes, picker a lower max value that you are comfortable with. It may need to be raised for colder weather (esp. if it's below freezing, there's rain and/or snow). I would use the scheduled charging so that you aren't at elevated SoC for too long.

 

Got it, so NREL (slide 8 of https://www.nrel.gov/docs/fy16osti/66708.pdf), Battery University, Google, Apple, Tesla, VW, Kia, Nissan, etc. are all wrong. There are more.

 

New technology or not, Li-ion batteries simply don’t like being kept at 100% charge for long periods of time without affecting lifespan. The recall was about high state of charge having an elevated level of fire hazard due to manufacturing defect.

So it’s safe to charge to 100% again with the new battery, but it has never been the case that it will not affect lifespan. That being said, I’ve been just charging to 100% whenever possible for the past 4.5 years - usually with DCFC no less - and it has not been much of a problem because the car is used daily and the charge doesn’t remain at 100% for very long.

 

But your Bolt isn't charging to 100%. Only to "usable" 100%. Not all of the battery is used to address this concern.

 

Thanks for explaining that after my 3 days of long driving I usually drive just in town and don't charge it for another 4 days and I go off the 290 mi peak and by the time I charge it four days later it still has 180 mi of range in it but I will take it down to 88% as far as the percentage goes cuz it never goes down to 20% even on my long trips and I've got a calculator that it'll still be it 28% even if I do an 88% hilltop

 

Both things can be true. Charging to 100% may indeed increase battery degradation, but for the Bolt, the difference may be imperceptible given all the other variables involved in battery degradation. Even manufacturing variations among individual cells may cause more noticeable degradation than anything you do in terms of charging to 100% or not.

I think it's fair to say that setting a target charge level below 100% may not significantly help, but it certainly won't hurt.

 

I think it's fair to say that setting a target charge level below 100% may not significantly help, but it certainly won't hurt.

Charge level is likely to make more of a difference if you charge it up and leave it parked for long periods of time at the charged-up level, compared to if you charge it up and then drive away shortly thereafter, using enough so that the car is later parked at a lower charge level after being driven for a while.

 

2021 Chevy Bolt. The battery still will not charge to 100 percent. I can post a photo. It’s still stuck where it was before the battery replacement. I could use the extra bit of juice.

 

Yes, a photo would be helpful.
Also, see item #5 in this post on the stickied recall thread:

Fire recalls summary and timeline - Updated 2/15/22

Timeline from the following: https://www.nhtsa.gov/vehicle/2017/CHEVROLET/BOLT/4%252520DR/FWD#recalls https://allev.info/2021/07/list-of-known-chevy-bolt-fires/ https://www.nhtsa.gov/vehicle/2020/CHEVROLET/BOLT%252520EV/5%252520HB/FWD#recalls 2020-2022 Chevrolet Bolt EV and EUV Defect Notice...

www.chevybolt.org

 

Listening to these guys talk shop, I am amazed any of these batteries last to 100K miles.

 

Ok, so at 100% on the dash, what is the actual soc percentage of the pack?

 

Nobody knows for sure. The Bolt has a PID (Parameter ID) that is readable by an ODB2 scanner, that has been labeled "Raw SOC." When I've charged to 100% on the dash, that PID is around 97%. However, consider the reasoning from Sean Graham, who argues that the PID is faulty and there is no buffer on the Bolt's battery:

Does the Chevy Bolt have a battery buffer? – All EV Info

allev.info

 

On my ioniq 5, the manual suggested charging to 100% once a month. (I believe it's to balance the cells.)
Is the same thing true of the bolt?

Sent from my SM-G973W using Tapatalk

 

On my ioniq 5, the manual suggested charging to 100% once a month. (I believe it's to balance the cells.)
Is the same thing true of the bolt?

Not in the 2017 manual. I have monitored cell voltages, and looked at scans of all 96 cell groups, many times. I have never seen the lower cells catch up, nor have I seen the highest cells burn off any excess. That was the case with the old pack until it bricked, and has been the case with the new pack for two months. For instance, #48 and #49 are much higher than the others now. I will be amazed if this ever changes.

 

On days that I drive Uber I need 100% capacity.

Now that I am driving Uber part-time, I am considering setting a limit, especially if I shift to driving on a couple days per week.

However, I do not necessarily know in advance which days I will drive Uber.

Once I have set say a 88% limit, do I have to go out to the car to gain a full 100% charge, or can I use the myChevy app to allow it to charge from 88-100% as soon as I know I want to drive Uber that day?

 

You actually have to go back to the infotainment screen go to charging and hit target charge and change it back up to 100% manually That's what I found anyway

 

I agree..I have used the app just before going to bed to make sure settings are set for timed charge or make sure doors are all locked, comes in handy. It only takes a few seconds to change target charging status.. great idea to sell it to GM!

 

.. great idea to sell it to GM!

What does that mean?!?