Battery charged 100%

bww129 said:

This is a key fact that most people have a hard time understanding about Lithium based batteries.

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I don't think it's the case that people don't understand that charging strategies affect battery wear; the question is how much the effect will be and much you should care.

By the time my Bolt hits 100,000 miles (which will likely take more than ten years), it will be at the equivalent of fewer than 500 cycles. At almost two years old, it's had the equivalent of about 60 cycles so far. At 500 cycles, differences between strategies are likely to be barely starting to show.

Worrying about making sure my Bolt's battery will be at 20% degraded at 5000 cycles rather than 35% degraded is ridiculous to me — it's never going to see 1 million miles.

Vertiformed said:

One other data point is that it is broadly believed that “100% charge” on the Bolt is not actually charging the battery all the way to its 100% maximum capacity, it's more like 96%, and likewise 0% is more like 4%.

It's also worth noting that there are many drivers who have charged their Bolts to 100% and seen pretty modest battery degradation. Bolts like Eric Way's (@NewsCoulomb) still have ample range even after lots of charging to 100% and many fast-charge sessions.

If you always treat your Bolt so that you don't dare charge it above 80% or run it down below 20%, it's like having a Bolt whose battery is already 40% (or more) degraded!

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After nearly 40K miles on my 2017 Bolt, I’ve not observed any noticeable battery degradation. I’ve always charged to 100% at home (level 2), never charged above ~80% when using DC Fast Charges, and never let the battery go down below ~10% charged. I even took a 1,200-mile trip earlier this year utilizing a succession of DC Fast charging stations. I say, go by the manual as Chevy has engineered battery protection into their product.

fcotamarez said:

About a month ago I bought the Chevrolet Bolt EV, I have heard that charging the battery 100% can cause damage to it. The manual says nothing about it. That's right?

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I own a 2017 Bolt with 35K miles, keep it fully charged with a level 2 charger and have seen no significant battery degradation in 2.5 years. It is on the charger whenever it is not being driven. I also own a 2016 Cadillac ELR (basically a version of the Chevy Volt) with a 16KWH battery, and have also kept it plugged in for 25K miles in 3.5 years, also with no significant battery degradation. I am unconcerned with how highly charged, and note that the ELR/Volt owner's manuals recommend keeping the cars plugged in when parked if possible (probably to maintain battery temperature at optimum). You can probably increase the life of the battery by not fully charging or discharging, but I don't think the level of degradation that occurs is of concern to the average user

Temperature extremes are another factor that effects battery performance and life. Plugging the car in when the temperature is below freezing causes the battery management to be more aggressive in keeping the battery warmer. Cold weather preconditioning brings the battery up to around 7c (40f or so) to get far out of the "reduced power" area (do what you feel confortable with the hill top setting). An added advantage is a warm car for the driver and it makes windshield deicing easier. The same scenario also applies to excessive heat (40c or 100f), but I don't have experience with that type of weather.

davidjmelv said:

You can probably increase the life of the battery by not fully charging or discharging, but I don't think the level of degradation that occurs is of concern to the average user.

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That's exactly why Chevy said up to 40% (from what I remember reading on here somewhere) degradation is acceptable over the 8 year warranty. It should cover 99% of cars sold if the cells are manufactured and assembled properly regardless of how the average user charges and discharges the battery. But what if you want to keep your car for longer (not the average user)? I had my last car for 18 years. Seems like a great idea to minimize degradation as much as possible so it still has good range well after the warranty runs out. If you don't plan on keeping the car for very long then you probably don't care, but the poor sap who gets the car after you will.