Chevy Bolt EV Forum banner
  • Hey Guest, welcome to ChevyBolt.org. We encourage you to register to engage in conversations about your Bolt.
1 - 20 of 25 Posts

Registered
Joined
197 Posts
I'm a new guy here, so don't put too much value in my comments. BUT, if charging your Bolt to 100% would "cause damage to your battery" then I think the Owner's Manual would at least mention that fact. Since it does not, I believe you can "safely" charge to 100%. I charge our Bolt to 100% every night (Level 1) and it has not (yet) exploded in a ball of fire.

The battery charging controversy arises when discussing how to best extend the useable life of the battery pack. This is the subject of the article linked above. Many opinions on this subject, so you should do some reading and decide for yourself how to manage your battery charging routine.
 

Registered
12/16 build, 2017, white LT
Joined
14,910 Posts
There are many opinions on the internet, but the facts are clear. All lithium ion batteries, currently produced, suffer greater degradation the closer your charge to full, and discharge closer to empty. There is no dispute on this matter among researchers, or battery makers. Most OEMs are obviously not going to bring this up. You can do whatever you like to the Bolt's battery, and it will not exceed 40% degradation in 8 years or 100K miles. If this is good enough for you, you needn't worry.
 

Registered
12/16 build, 2017, white LT
Joined
14,910 Posts
Here are some Torque Pro screen shots of our 2017 Bolt LT at full, half, three bars, and empty. Unless leaving on a long trip, our Bolt is only charged to "hilltop", which is typically 87%-89%. We seldom get down to 3 bars.

Font Screenshot Office equipment
Font Screenshot Games
Font Screenshot Games Icon
Font Screenshot Games
 

Registered
Joined
5 Posts
Discussion Starter · #8 ·

Registered
2022 Bolt EUV Nov build
Joined
9,591 Posts
I personally aim for 80-85%. If I do not recharge sooner, that's enough range for 5 days of commuting (getting down to 10-20%). I tend to recharge daily in between my 2 morning stops with time gap at a free L2 station. Then a longer charge to get back up to 80% when I get between 40-60%.

For longevity, general consensus is to keep it between 40-80%.
 

Registered
Joined
4,498 Posts
There are many opinions on the internet, but the facts are clear. All lithium ion batteries, currently produced, suffer greater degradation the closer your charge to full, and discharge closer to empty. There is no dispute on this matter among researchers, or battery makers. Most OEMs are obviously not going to bring this up.
Nissan used to really emphasize the above on model year '11 to '13 Leafs in the manual, esp. the high state of charge portion, until they removed the 80% limiter option on US '14 Leafs. (I've had a '13 Leaf for over 6 years and had been following Leaf at least a bit since before it went on sale.)


In model year '14, 75 miles looks near bottom of the barrel vs. other sub-100 mile EVs of the time while 84 miles looks near top of class.

AFAIK, Tesla has also emphasized not charging to full unless needed (e.g. for a road trip) in their documentation and UI in the car.
 

Registered
Joined
2,129 Posts
One other data point is that it is broadly believed that 鈥100% charge鈥 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!
 

Registered
12/16 build, 2017, white LT
Joined
14,910 Posts
One other data point is that it is broadly believed that 鈥100% charge鈥 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%.
You don't have to believe anything. It is all right there on Torque Pro. Look at the screen shots I posted. The cells, when charged to "full" are below 4.2 volts, and at "empty" they are above 3.2 volts.

If Jeff Dahn is right, it will all be moot soon, and Tesla will own the EV space.

 

Registered
2022 Bolt EUV Nov build
Joined
9,591 Posts
You don't have to believe anything. It is all right there on Torque Pro. Look at the screen shots I posted. The cells, when charged to "full" are below 4.2 volts, and at "empty" they are above 3.2 volts.

If Jeff Dahn is right, it will all be moot soon, and Tesla will own the EV space.

I am trying to keep my Bolt EV to retirement and beyond. 40-60% is more than enough for my daily commute. I est to need about 50 cycles per year, so 500 per decade and 1000 over 20 years.

1C rate means discharing at 60KW continuously. However, the Bolt is rated to go about 3.66 hours @ 65mph (60KWh battery), so it's averaging at 0.27 C. Another great news for longevity.
 

Registered
Joined
1,527 Posts
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!
It's not all-or-nothing though. It's not that you battery instantly gets damaged when it hits 100%. Rather, damage accumulates over time (regardless of SoC), it just accumulates faster at high/low SoC. Having a 40% degraded battery doesn't matter to me day-to-day.

Most of the time, I drive less than 30 miles per day. I charge every 3-4 days to Hilltop Reserve (~89%). However, when I do leave town, I don't hesitate to charge to full. Typically it doesn't sit at full for very long, as I am planning on hitting the road. This is when it counts to have a non-degraded battery.
 

Registered
Joined
1,594 Posts
I hadn't realized the warranty only covered in cases of >40% degradation. That's not a huge amount of confidence on GM's part. Granted so far people seem to be seeing only very modest loss, so hopefully it remains only an academic concern.
 

Registered
2022 Bolt EUV Nov build
Joined
9,591 Posts
I am trying to keep my Bolt EV to retirement and beyond. 40-60% is more than enough for my daily commute. I est to need about 50 cycles per year, so 500 per decade and 1000 over 20 years.

1C rate means discharing at 60KW continuously. However, the Bolt is rated to go about 3.66 hours @ 65mph (60KWh battery), so it's averaging at 0.27 C. Another great news for longevity.
Correction, so cycling 40-60% daily would mean probably 300 cycles a year, so 3k per decade and battery degradation of 15% and 6k cycles. I would be retired by then and driving very little. But assuming I drive just as much and extending to 20 years with 6k cycles, degradation would be 30%, leaving me with 70% capacity - still more than enough for travels in the area, including neighboring cities, in one charge.
 

Registered
Joined
1,527 Posts
Correction, so cycling 40-60% daily would mean probably 300 cycles a year, so 3k per decade and battery degradation of 15% and 6k cycles. I would be retired by then and driving very little. But assuming I drive just as much and extending to 20 years with 6k cycles, degradation would be 30%, leaving me with 70% capacity - still more than enough for travels in the area, including neighboring cities, in one charge.
A "charge cycle" is full-empty-full. If you are cycling 60-40-60, that's only 20% delta, which is much less stressful than 100%. In fact, cycling 60-40-60 five times is better than 100-0-100 one time. Your battery should last a very long time unless there is some unforeseen catastrophic failure.
 

Registered
Joined
72 Posts
A "charge cycle" is full-empty-full. If you are cycling 60-40-60, that's only 20% delta, which is much less stressful than 100%. In fact, cycling 60-40-60 five times is better than 100-0-100 one time.
This is a key fact that most people have a hard time understanding about Lithium based batteries. Battery chemistries differ to suit what the manufacturer wants from the cells, but the overall trend seems to hold true. The assumption is that your car will be used on a regular basis. Keeping your battery at full, or worse at empty, for extended periods of time (months), is also detrimental to cell health. This has also been shown in various studies, however each cell chemistry is different. Based on various articles, it seems as though GM specified a more mediocre cell chemistry to allow future expansion to higher energy density cell chemistires (more mi/kW) whereas Tesla chose a more aggressive chemistry but is dialing back the range because some users are pushing the batteries too hard. It's all a trade off in the auto industry, but I'm hoping GM played it on the safe side because we hope to own our Bolt for another 8-10 years after which we would consider battery service (individual cells, hopefully not the whole pack) part of the typical EV maintenance.
 
1 - 20 of 25 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top