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There are many articles, commentary on preserving battery life AND the state of charge. Many about Teslas.

1. Regarding the Bolt, what is the ideal usage pattern to maximize battery life (daily use permitting)? ie: Charging to 80%....using down to 30% and then charging again to the 80%? Or is it better to simply keep topping it off after each use?

2. What is the actual capacity of battery AND what is the usage capacity? On a full discharge (near full discharge), I reached almost 60 kW/h.

Thx
eric
 

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I would obey lithium battery best practices.
The Bolt is new so there is not the breadth of historical data like the owners of other older EVs.
That being said, the Bolt does have a lithium ion battery and so those rules do apply since they are based in physics and chemistry.
From my own reading and viewing of battery best practices, here is some info I have found on charging.

Charging to 80% is a typically a good idea.
Especially if you drive in L then you want to leave a little headroom so you are recouping as much as possible.
Lithium batteries have a optimal state of charge around 50%.

Charging to 100% for when you need it is okay but it's good to not do so unless it's needed for say longer trips.
It's not good to leave your battery sitting charged at 100% for extended periods of time.
Its not good to discharge a battery too low either. (I use the same percentage 80% full and 20% to remain as a guide, but probably oversimplifying)

Lithium batteries have a optimal operating and charging temperature of around room temp.
Hot and cold temps affect range and battery life, again physics and chemistry.
The Bolt does have battery cooling/heating (conditioning) which may helps reduce the risks from quick charging but only time will tell.
Quick charging frequently (like twice a day) is not good for any battery.

Not sure on actual capacity and usage capacity but maybe some other members have more insight than a newb like myself can provide.
 

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BoltR said it all. Usable capacity is ~60 kWh, actual probably 10% higher. Car manufacturers are always a bit vague about total capacity...probably because that number starts dropping from the original formation charge, and continues going down after that.
 

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A few things to add/correct.

Temperature does matter for Li-Ion batteries. Heat is the enemy, that can actually affect capacity of the cells. However cold while it will temporarily reduce available capacity it will not affect it long term. You can freeze a Li-Ion battery and you would be able to get nothing out of it, essentially making it appear dead. However if you turn around and warm that battery up into its normal operating range, it will retain the same capacity it had before. Cold does not cause capacity changes within the Li-Ion cells, heat does.

Saying there is a single optimal SOC to have a Li-Ion battery at is also rather misleading as it varies quite a bit based on the exact chemical makeup of the batteries, electrode type, solution makeup, etc. There have been studies done on the cells Tesla used in the earliest Model S already and it was shown even leaving them at a 100% SOC they only lose fractions of a percent in capacity per year, 0.35%. I don't know what the optimal SOC for the battery in the Bolt is though but I am not concerned with leaving it at 100%.

Most the stuff BoltR posted is "best practices" for Li-Ion batteries, but almost all of it is based on taking care of Li-Ion batteries that don't have active thermal management. Like our phones, laptops etc. Those ideas really haven't been fully tested on cars with immense Li-Ion batteries and that have active thermal management.

Now I am not saying to ignore it all because of that but you should take it with a grain of salt. GM actually spent a petty immense amount of money and time testing these batteries. They built an entire environmental facility where they tested them over a lot of charge/discharge cycles in many different environments with and without the active thermal management system.

The two most dangerous things for Li-Ion cells we don't have direct control over. That is overcharging and heat. It doesn't matter what SOC you leave the battery at, the charger in the car and the computer controlling determine if any of the cells get overcharged (the goal is not too of course) and this is why charging slows significantly towards the higher charge states. Heat, well long as we keep it plugged in or charged over 30% the thermal management system in the car is supposed to keep it in the optimal temperature range, I believe GM does 32 - 90 degree F as their range.

GM recommends to leave the car plugged in even when fully charged, that is so the thermal management system is always running without needing to use the battery for it. It can of course use the battery for it but using current from the battery causes more heat to build up in the battery so it is most optimal to have an outside power source doing the work.

So to me I am not concerned at all with SOC of the battery. My goal is to always do what I can to limit the amount of heat the car is exposed to. Keep it in garage when not in use, plugged in when not in use, parked in shade if out and about if it is hot or warm and sunny. I charge each night at home, though I do use hill-top not for SOC concerns but just so I always have full regen braking capacity. There is also something to be said for smaller more often charge cycles as compared to less frequent longer charge cycles. Charging can build up quite a bit of heat in the battery. Longer charge cycles just mean more heat and longer charge cycles. As heat builds up in a Li-Ion battery the internal resistance is increased, meaning it takes longer to charge.

So I guess that was a lot to just say, control the heat the battery/car is exposed too.

If you want to nerd out on some studies around thermal an d Li-Ion battery issues, this is the paper to read. It is from 2011 but it is quite good.
http://jes.ecsdl.org/content/158/3/R1.full
 

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I posted this on another thread but this link has a video that talks about and a interactive spreadsheet on tesla model s batteries. They collected a bunch of data directly from owners on their batteries, miles, charges, area, etc and put it all in a spreadsheet. You can use that just to see how well their batteries are holding up to real world use.

https://teslanomics.co/tesla-batteries-last-forever-basically.html

This link is a comparison insideevs did of the thermal management systems Tesla and GM uses, it actually rates GM to have an advantage for heat removal.

http://insideevs.com/tesla-or-gm-who-has-the-best-battery-thermal-management-bower/

So I think it is fair to expect the batteries in the Bolt to have similar lives as compared to Tesla batteries which we have more data on.
 

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The absolute worst thing you can do to a lithium ion battery is charge it when the battery is at freezing. It WILL destroy the battery. Overcharging, and over discharging can also ruin a battery. No modern EV will let you do any of these, if it is functioning properly. As to things we, as owners, can do to affect longevity:

https://electrek.co/2017/09/01/tesla-battery-expert-recommends-daily-battery-pack-charging/
If the Bolt actually attempted to charge a frozen battery that would be the worst fail imaginable. With all the sensors inside the battery to know the temperature of the cells I would certainly hope it is smart enough to not let it charge until it got them within the acceptable temperature range.

With the way GM setup and design the Bolt I just don't think there really are many things we can actively do that will significantly change degradation assuming we treat the car according to their instructions for care of the battery. Leave it plugged in when you can, follow storage procedure if it will be stored not plugged in for long periods of time. All the rest of it the Bolt is trying to take care of or does take care of itself.

Battery capacity is listed as 60 kWh, that is usable capacity, not true capacity. The Bolt battery has 288 cells at 63ah and 3.65v (best information I can find) which gives an actual true capacity of 66.25 kWh which means even if you charge to 100% each night you are in reality only charging to about 90%, if you hill top charge each night now you are actually only charging to 80% or a little less. So the battery is actually built to never allow a true 100% charge and by settings available it encourages you to only charge to 80% each charge cycle.

The battery has active thermal management and the cells use a nickel-rich lithium-ion chemistry which is one of the more heat tolerant chemistries, it can run at higher temps than other li-ion batteries before it gets damaged and loses capacity. The higher running temperature range also means that the internal resistance due to heat builds up slower than some other battery chemistries would. High heat is still bad for this battery, it just has a little extra wiggle room.
 
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