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I've recently read tech articles that state charging your battery to only 80% could double the battery life. The Bolt manual basically states you should keep your car fully charged whenever possible. So what's a Bolt owner to do? Use hilltop reserve and fully charge? Don't worry, Chevy already has the best charging practice built in? All opinions are appreciated.
 

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Yep, this is why many of us use hill top reserve. Even though we don't live on a hill top. Looking at the recent article it also states number of cycles with each charge level. Looking at 90% and charging once a week, I should get 15 years easily. My fear, living in the hot southwest, that heat will be my killer despite my best efforts. I'm hoping the car will condition the battery if above 30% state of charge when ambient temperatures exceed 90 degrees. And that's just in my garage. I've already come close.
 

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Don’t believe that GM treats what your see 90% as the battery’s true 90%. GM designed the car and battery to last.

But whatever. Use hilltop.
 

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article posted on other thread. reposted here for convenience: https://electrek.co/2018/05/04/are-you-killing-your-lithium-batteries/

Graph in article shows what cell voltage is for lithium ion for each percentage.

110% (4.3V)
100% (4.2V)
90% (4.1V)
80% (4.05V)

82% (3.96V), clearly providing a buffer from this post from @drdiesel1: http://www.chevybolt.org/forum/235026-post52.html
@LaBrother had his Bolt top out @4.12V at a full charge. http://www.chevybolt.org/forum/293626-post68.html

Clearly this provides a 10% buffer. So if we use hilltop, then we are indeed approaching the 80% SOC.
 

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For my commute which worse case in the winter used 60% of my SOC, I'll stick to using 100% SOC from November through April and using Hilltop Reserve May through October.
 

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Today was our first 100 degree day of the year but it surely won't be the last. My (Nightfall Grey) bolt was sitting outside unplugged at ~60% SoC. No idea if the car could or would do any kind of cooling in this situation.

I understand there's a battery heater system that kicks in but only if the car is "on" or if it's "plugged in" (don't know if this is L1 and L2 or just L2).

Does the battery cooling work the same way? Will it only turn on the AC compressor and cool the battery if the car is "on" or plugged in.

I wonder if people (like me) who are trying to manage the maximum SoC are doing themselves a disservice. Are we better off (at least on hot days) plugging in and letting the car charge to 90% but being plugged in allows the car to cool the battery when needed?

Would sure be nice to be able to directly control the maximum SoC other than just have Hilltop Reserve. If I could ensure that the car would never go above 80% except when I told it do I'd leave it plugged in every night and weekend.
 

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Battery conditioning works whether you're plugged in or not,
so long as your battery has at least 30% charge. And any time that you're plugged in.
Dunno' where in the heck the only-when-plugged-in-or-turned-on idea came from.
 

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Battery conditioning works whether you're plugged in or not,
so long as your battery has at least 30% charge. And any time that you're plugged in.
Dunno' where in the heck the only-when-plugged-in-or-turned-on idea came from.
It comes from GM saying in the manual that if it's hot out, you should plug in or it'll affect the life of your battery.
 

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It comes from GM saying in the manual that if it's hot out, you should plug in or it'll affect the life of your battery.
Not a practical suggestion for most Bolt owners, unless they never drive anywhere when it’s over 90 degrees, or only drive to locations with available chargers.

Many states regularly have temps over 90 for much of the summer. Should we all stay home?
 

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It comes from GM saying in the manual that if it's hot out, you should plug in or it'll affect the life of your battery.
yep, page 30:

Vehicle Charging/Maintenance Charging

Keep the vehicle plugged in, even when fully charged, to keep the battery temperature ready for the
next drive. This is important when outside temperatures are extremely hot or cold.
 

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Yes, because battery conditioning takes juice, and if it's not plugged in,
it drains the battery to condition, down to, I believe, 30% SOC.
 

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If we consider that the apparent inconsistencies in GM's recommendations are probably intended as CYA statements crafted by the legal department, then it is our job as Bolt owners to refer to the best studies/recommendations from other sources to supplement what GM is or isn't really telling us. If/when the weight of evidence from five or ten years' worth of data from the entire EV community demonstrates the most effective way to minimize battery degradation over the life of your auto, the nature of the CYA statements from legal will eventually change as well.
 

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Just made a slight modification to my house air conditioning. Today, my garage hit 88 degrees Fahrenheit. Approaching the dreaded 90 degrees Fahrenheit where the manual recommends leaving the Bolt plugged in. My garage is insulated, but doesn't have any cooling. With the day night cycle, the garage has been getting warmer and warmer each day, where the garage is approaching the outside temperature.

Being in the dry southwest, the house is cooled with evaporative coolers. We leave windows open during the summer to allow air flow through the coolers. Cool air just being dumped outside. That's when it occurred to me, why not try to get some of that air to the garage. That's when I made the mental connection to the heating system return air ducts. One set goes to the heater in the garage. Bingo. Took the front door off the heater and pulled the filter. Now cool air is going into the garage. We'll see if that keeps the garage below the 90 degree Fahrenheit threshold this summer.
 

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If we consider that the apparent inconsistencies in GM's recommendations are probably intended as CYA statements crafted by the legal department, then it is our job as Bolt owners to refer to the best studies/recommendations from other sources to supplement what GM is or isn't really telling us. If/when the weight of evidence from five or ten years' worth of data from the entire EV community demonstrates the most effective way to minimize battery degradation over the life of your auto, the nature of the CYA statements from legal will eventually change as well.
Let’s hope that in five or ten years battery technology will have improved to the point where babying the battery isn’t necessary. EV batteries should be able to be charged to 100% and operated in all conditions without having to worry about any significant performance degradation.

GM’s current battery warranty allows for up to a 40% degradation as “normal”. I don’t think any Bolt owner would consider a drop in range from 238 miles to 143 miles to be normal or acceptable.

This article on plugincars goes over the battery degradation issue, and basically advises most EV owners not to worry, as severe battery degradation is rare:
http://www.plugincars.com/what-you-need-know-about-electric-car-battery-warranties-132884.html
 
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Apologies Dumb question: when GM says "plugged in" do they mean with charging actually enabled or just plugged in?
Well, if it’s plugged in but the EVSE is off that wouldn’t do much.
 

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Well, if it’s plugged in but the EVSE is off that wouldn’t do much.
Ok but seems like a very silly excercise to do every night in Georgia when it's 90 degrees from May to October. Since my commute is 20 miles I just wonder how much good it's going to do and even if the charge setting is set to Hilltop reserve. I wonder if one is doing more harm to the battery....
 

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Ok but seems like a very silly excercise to do every night in Georgia when it's 90 degrees from May to October. Since my commute is 20 miles I just wonder how much good it's going to do and even if the charge setting is set to Hilltop reserve. I wonder if one is doing more harm to the battery....
Your Bolt will be sitting at work all day all summer. Unless you have chargers at work your car will be spending a lot of time in summer heat without being plugged-in. What effect, if any, that will have on battery degradation is anybody’s guess.

The battery thermal management is designed to work whether or not the car is plugged-in. It’s not clear what advantage there is to having the car plugged-in, other than preventing a slight battery drain in very hot or cold weather. There is certainly no requirement that the Bolt be plugged-in, it’s only a GM recommendation, and one that doesn’t come with an adequate explanation as to why it’s better to be plugged-in than not.
 

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:)My Bolt is a lease, but it's mine until I return it. I'll return it in good condition, with lower mileage than I'm allowed. When I charge, I charge to 100%. Call me selfish or ignorant, but I'm charging to 100%.
 
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