[Nebula]

Have anyone ever noticed how long the Bolt sits at 100% before completing the charge? I waited over 10 minutes just to unplug it before the Bolt finished finalizing. I know it wasn’t completely finished as it was still drawing 5 kilowatts.
should I have let it sit longer? I have a feeling it was equalizing the battery voltage.

 

[Killravyn]

Have anyone ever noticed how long the Bolt sits at 100% before completing the charge? I waited over 10 minutes just to unplug it before the Bolt finished finalizing. I know it wasn’t completely finished as it was still drawing 5 kilowatts.
should I have let it sit longer? I have a feeling it was equalizing the battery voltage.

The only thing I can ask is… No you need to wait. I put mine and bare minimum 40% and when the car was still above 40% still with drawl power almost up to 4:55 kW of power I assumed it was recharging the 12 V battery in the car… A.k.a. it’s number one Achilles heel as a result of if that battery goes dead you’re screwed in the whole car is dead in place. Sorry for the long poorly worded statement

 

[Nebula]

The only thing I can ask is… No you need to wait. I put mine and bare minimum 40% and when the car was still above 40% still with drawl power almost up to 4:55 kW of power I assumed it was recharging the 12 V battery in the car… A.k.a. it’s number one Achilles heel as a result of if that battery goes dead you’re screwed in the whole car is dead in place. Sorry for the long poorly worded statement

Interesting. So you’re saying I should have let it completely finish as it was likely charging the 12v battery. Hmm. I’ve never seen it behave that way when setting the target charge below 100%. Today was my first go at charging to 100%. Typically, I set the target charge to 80%. The car finalizes the charge for a moment, then completes the session. However, this did not happen with the Bolt set to fully charge. Honestly, I probably let it “Finalize” for more than ten minutes before getting impatient and unplugged it. Strange.

 

[wesley]

Assuming that the car isn’t doing other stuff like propulsion battery conditioning for high/low temperatures or recharging the 12V battery, the main reason why it keeps charging when the state of charge (SoC) hits 100% is because it’s really not actually done charging.

There are two SoC data kept by Bolt. One is displayed, which you normally see on the dashboard or MyChevrolet app. The other is raw, which is the ”true” internal number. Bolt keeps a buffer at both extremes of the SoC to mitigate battery degradation. When displayed SoC is at 0%, raw SoC is at around 4-5%, and 100% displayed means 95-97% raw.

Now, as you charge yout Bolt, it will show 100% displayed As soon as 95% raw is reached. However, the car is able to keep charging a bit extra to around 96-97% raw if you don’t stop. In my experience, this takes about 15-20 more minutes of charging at a 7kW L2 charger. So it’s effectively charging your car to 101-102% although it doesn‘t show it that way.

 

[tangolima]

Most of the time, can't say all the time, the battery cooling turns on at the end of charge to cool the battery. It would be the best thing to let it finish bringing the battery temp to the preferred window. No big deal if you don't. The car will use the battery to accomplish it if it really has to.

-TL

Sent from my SM-N960U using Tapatalk

 

[Nebula]

Assuming that the car isn’t doing other stuff like propulsion battery conditioning for high/low temperatures or recharging the 12V battery, the main reason why it keeps charging when the state of charge (SoC) hits 100% is because it’s really not actually done charging.

There are two SoC data kept by Bolt. One is displayed, which you normally see on the dashboard or MyChevrolet app. The other is raw, which is the ”true” internal number. Bolt keeps a buffer at both extremes of the SoC to mitigate battery degradation. When displayed SoC is at 0%, raw SoC is at around 4-5%, and 100% displayed means 95-97% raw.

Now, as you charge yout Bolt, it will show 100% displayed As soon as 95% raw is reached. However, the car is able to keep charging a bit extra to around 96-97% raw if you don’t stop. In my experience, this takes about 15-20 more minutes of charging at a 7kW L2 charger. So it’s effectively charging your car to 101-102% although it doesn‘t show it that way.

Very interesting. Thank you for the reply. How did come to have this knowledge? I’d love to know. I’ve been looking into getting the OB 2 reader, but I’m not sure which one to get. Is that what you used or how you came to figure this out?
Thanks again. Great information!

 

[Nebula]

Most of the time, can't say all the time, the battery cooling turns on at the end of charge to cool the battery. It would be the best thing to let it finish bringing the battery temp to the preferred window. No big deal if you don't. The car will use the battery to accomplish it if it really has to.

-TL

Sent from my SM-N960U using Tapatalk

I did hear the battery fan kick on when it hit 91 percent. It actually scared me a bit, thinking something was wrong, as I’ve never heard it.

 

[SparkE]

Um, no. no. no. no.

You don't 'need' to wait. I can't tell if you are talking about fast charge ("DCFC") or simple 'regular' charging, either level 2 (240V) or level 1 (120V).

At any rate, when the car is "on" (ready to drive) it is 'charging' the 12V battery. When you are driving, it is 'charging' the 12V battery (as needed). You don't need to leave it ALWYS plugged in.

On the other hand, it is probably a good idea to leave it plugged in "after full charge" maybe once a month to "balance cell voltage" across the battery pack. It's not really an issue unless you drive down under 5% of battery capacity (which generally isn't a good idea, but is fine a few times a year, if needed to get where you are going). And by "full", I mean "charging stop point" - the battery will cell balance after reaching "hill top reserve" as well, if you have that set (also probably a good thing to do IN GENERAL - not a big deal if you charge to 100% when you know you will need the extra range).

 

[Nebula]

Um, no. no. no. no.

You don't 'need' to wait. I can't tell if you are talking about fast charge ("DCFC") or simple 'regular' charging, either level 2 (240V) or level 1 (120V).

At any rate, when the car is "on" (ready to drive) it is 'charging' the 12V battery. When you are driving, it is 'charging' the 12V battery (as needed). You don't need to leave it ALWYS plugged in.

On the other hand, it is probably a good idea to leave it plugged in "after full charge" maybe once a month to "balance cell voltage" across the battery pack. It's not really an issue unless you drive down under 5% of battery capacity (which generally isn't a good idea, but is fine a few times a year, if needed to get where you are going). And by "full", I mean "charging stop point" - the battery will cell balance after reaching "hill top reserve" as well, if you have that set (also probably a good thing to do IN GENERAL - not a big deal if you charge to 100% when you know you will need the extra range).

I was DCFC. I’m assuming the cells balance at any target charge correct? I don’t have hill top reserve. The lowest I’ve run the Bolt is 22%. Today was the first time I have put the target charge to 100%. I was testing out the charge time from 22 - 100.

 

[wesley]

Very interesting. Thank you for the reply. How did come to have this knowledge? I’d love to know. I’ve been looking into getting the OB 2 reader, but I’m not sure which one to get. Is that what you used or how you came to figure this out?
Thanks again. Great information!

Yes, it's the result of analyzing nearly two years' worth of data from my OBD-II reader.

 

[Nebula]

Yes, it's the result of analyzing nearly two years' worth of data from my OBD-II reader.

What model OBD-II reader do you have? I’m currently looking for one.
Thank you.

 

[wesley]

What model OBD-II reader do you have? I’m currently looking for one.
Thank you.

I'm using the LELink Bluetooth LE OBD-II reader. I have the EngineLink LE app on my iPhone to connect to it.

 

[Sean Nelson]

Have anyone ever noticed how long the Bolt sits at 100% before completing the charge?

I tested a DC fast charge to 100% a couple of years ago and it took around 18 minutes to stop after having reached 100%. That's the only time I've sat and watched it.

 

[SparkE]

I don't fast charge to 100%. Heck, I rarely fast charge past 75%. If I needed the miles to make it to the next DCFC I would, but I don't road trip in my EV (I am too lazy to wait while charging and I hate sitting around, or walking around, parking lots). I have found all the 'local' L2 chargers where I can park the car and walk home, then walk back a few hours later to pick up the car. Adding that exercise to my weekly schedule has meant me losing over 10 lbs during the past year.

 

[Sean Nelson]

I don't fast charge to 100%. Heck, I rarely fast charge past 75%.

I don't normally fast charge to 100% either, I just did it the once to see how long it took.

 

[Entropy512]

One other observation:
If you are plugged in, and fully charged, but then initiate a precondition cycle with an EVSE not capable of 32A (in my case, mine is set to 24) - The cabin heater will spend a few minutes pulling more power than the EVSE can supply, so it takes the battery down below target. Expect 10-15 minutes at 24A in this particular scenario.

 

[Voldar]

Bolt keeps a buffer at both extremes of the SoC to mitigate battery degradation. When displayed SoC is at 0%, raw SoC is at around 4-5%, and 100% displayed means 95-97% raw.

Not really true. Can you provide a link stating the above ?
The Bolt EV maybe has a buffer at the low, but definitely not at the max. Or else how you explain the fact that you can't send electrons in the battery (no regen) when the battery is full (100% SOC).

 

[Entropy512]

Or else how you explain the fact that you can't send electrons in the battery (no regen) when the battery is full (100% SOC).

Same way that Bolts with the temporary recall workaround taper to 80 instead of abruptly stopping at 80 - in a charging system that has CC and CV phases, nothing stops you from dropping the CV limit below what the battery chemistry is capable of.

Heck, GM could arbitrarily lock out regen anywhere above 50% if they wanted to. There's no legitimate reason to do so, but they could.

You can easily force electrons into a battery past what is generally accepted as 100% charge for that chemistry. One of two things will happen:
1) You won't light the battery on fire, but you will trigger rapid degradation
2) You'll light the battery on fire

BTW, both of these are why all safe lithium ion chargers have a constant voltage (CV) termination phase. (Bolt owners call this "taper" when on DCFS.)

 

[Voldar]

Same way that Bolts with the temporary recall workaround taper to 80 instead of abruptly stopping at 80 - in a charging system that has CC and CV phases, nothing stops you from dropping the CV limit below what the battery chemistry is capable of.

Heck, GM could arbitrarily lock out regen anywhere above 50% if they wanted to. There's no legitimate reason to do so, but they could.

You can easily force electrons into a battery past what is generally accepted as 100% charge for that chemistry. One of two things will happen:
1) You won't light the battery on fire, but you will trigger rapid degradation
2) You'll light the battery on fire

BTW, both of these are why all safe lithium ion chargers have a constant voltage (CV) termination phase. (Bolt owners call this "taper" when on DCFS.)

I understand the notion of "usable" vs "raw", but for me, a buffer is something "usable".
In the Volt you could "burp" the battery. I am not sure it can be done the same for the Bolt EV. When you drive past the 0% SOC and you are still moving, that’s a "buffer" for me.
The limitation of a charge over a set % of SOC isn’t the same as the setup of a buffer. I might be wrong though.
I think, if I am not mistaken, there was a video on YouTube or someone did the math based on Ah per cell of a Bolt EV and the end result was that the Bolt EV doesn’t really has a "raw" capacity. What it has, it uses all. Again, I might be mistaken.

 

[p7wang]

This is my readings off my Bolt EUV. 190.48 Ah x 398.31V = 76 kWh raw? My usable is 61 kWh.