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Discussion Starter #1
So I got a new JB Pro 40 wifi and just did a test charge on my 2019 Premier. I do not do scheduled charging.

1) I believe the OEM EVSE charger tapers the charge at the end of the cycle. The JB Pro seems to go to the desired charge setting I make and then stop, no tapering of charging current.
Do I need to be concerned about this?

2) The app has a dial that you set for charging. I have to set current SOC on left side of screen and desired SOC on right side of screen. This seems very cumbersome. Is there an easier way to charge?
What happens if I just plug it in? I guess if the settings are not set it might do nothing at all. There is a setting for "Min Charge". Maybe I should just use that and set it to 57kW which will be nearly a full charge. Anyone using that setting for immediate charge?

3) I have my Infotainment charge setting to 95% which I think on earlier Bolts is the HillTop setting, I figure that 95% is 57kW. Presumably that setting is not applicable when using the JB. Is that correct?
I set the JB desired SOC to 57kW. When charging with the OEM EVSE that was a full charge (I think) and it reset the numbers on the Infotainment "Energy Information" "Energy Detail" back to 0. After my JB charge to 57kW those settings remain as they were before I charged. Is this because I did not charge to 100%? Is there something else I'm not doing right? There is a reset on a different screen, but it also resets a lot of other useful info. I don't recall doing that when charging with the EVSE charger.

4) When the charge was finished, OnStar started sending me alert notifications that charging was stopped due to an interruption. Well, yeah, charging was finished. The alerts just kept coming one after the other until I texted STOP and that apparently cancelled all On/Star notifications. So I guess I have something set up incorrectly here also. Any ideas?

I don't put on many miles in a day so it will be a few weeks before I use enough kW before I do my next charge.
 

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So I got a new JB Pro 40 wifi and just did a test charge on my 2019 Premier. I do not do scheduled charging.

1) I believe the OEM EVSE charger tapers the charge at the end of the cycle. The JB Pro seems to go to the desired charge setting I make and then stop, no tapering of charging current.
Do I need to be concerned about this?

2) The app has a dial that you set for charging. I have to set current SOC on left side of screen and desired SOC on right side of screen. This seems very cumbersome. Is there an easier way to charge?
What happens if I just plug it in? I guess if the settings are not set it might do nothing at all. There is a setting for "Min Charge". Maybe I should just use that and set it to 57kW which will be nearly a full charge. Anyone using that setting for immediate charge?

3) I have my Infotainment charge setting to 95% which I think on earlier Bolts is the HillTop setting, I figure that 95% is 57kW. Presumably that setting is not applicable when using the JB. Is that correct?
I set the JB desired SOC to 57kW. When charging with the OEM EVSE that was a full charge (I think) and it reset the numbers on the Infotainment "Energy Information" "Energy Detail" back to 0. After my JB charge to 57kW those settings remain as they were before I charged. Is this because I did not charge to 100%? Is there something else I'm not doing right? There is a reset on a different screen, but it also resets a lot of other useful info. I don't recall doing that when charging with the EVSE charger.

4) When the charge was finished, OnStar started sending me alert notifications that charging was stopped due to an interruption. Well, yeah, charging was finished. The alerts just kept coming one after the other until I texted STOP and that apparently cancelled all On/Star notifications. So I guess I have something set up incorrectly here also. Any ideas?

I don't put on many miles in a day so it will be a few weeks before I use enough kW before I do my next charge.
There is no good reason to be telling the JuiceBox to limit the charge to a set amount. Let your Bolt control the charging without any limits at the JuiceBox end.

Making the JuiceBox cut-off the Bolt will have the Bolt complaining about a charge interruption just as you experienced, and an incomplete charge.
 

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1) I believe the OEM EVSE charger tapers the charge at the end of the cycle. The JB Pro seems to go to the desired charge setting I make and then stop, no tapering of charging current.
Do I need to be concerned about this?
The EVSE is the power supply - both the stock (OEM) one that came with the car, as well as the JB. The "charger" is in the car (it converts AC power to DC). The car tapers the charge, not the EVSE.
 

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The EVSE is the power supply - both the stock (OEM) one that came with the car, as well as the JB. The "charger" is in the car (it converts AC power to DC). The car tapers the charge, not the EVSE.
Does the charger taper if you're using an L2 EVSE? I know it tapers for DCFC, but I'm not sure about L2.
 

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I messed with the juicebox app before I realized it's more of a pain than anything. Leave current charge at zero and charge limit to max. Trust me on this one.

Since the JB doesn't query the car for SOC, it only knows what you last set it to. If for example:

*you set the SOC in JB to 50%
*charge to 100%
*deplete battery to 30%
*forget to update SOC next charge
*JB will assume SOC of 50%, and only deliver 30kwh... stopping you at 80% SOC

Set charge limit in the car, not the JB. Only use than app for viewing data.
 

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The reason the JB lets you change the charge limit is to accommodate cars (like the 2017 and 2018 Bolt) that don't let you define a specific maximum charge level. If I wanted to charge to 75% (where I normally try to charge to) in my 2017 I can't control that with the car so I could tell the JuiceBox to stop charging at 75%.

Since you have a 2019 with the target charge setting on your car there's no reason to not tell JB to charge all the way, this will give all the control to the car which is what you want in your situation.

If the car is in control of the charge it's what decides to taper the charge near the end of the charge cycle (which will be dependent on whatever you have in your target charge setting), if you let JuiceBox do it the charge will cut off abruptly and you will not get the charge tapering and cell balancing cycle.

FYI, the "Hilltop Reserve" feature on the 2017 & 2018 Bolts is closer to 90% SoC than 95%, there seems to be some variance from car to car but usually my car will reach "full" on a Hilltop Reserve charge at 89%. I actually manually interrupt my charge at between 75% and 80% because I'm trying to preserve my battery capacity as much as possible for the long term and I only charge to "full" (about 89%) every 1000 miles or so just so my car can get the cell balancing effect. If I had the target charge setting I'd set it at 75% and leave it there unless I was going on a longer drive that required a fuller charge.
 

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I messed with the juicebox app before I realized it's more of a pain than anything. Leave current charge at zero and charge limit to max. Trust me on this one.

Since the JB doesn't query the car for SOC, it only knows what you last set it to. If for example:

*you set the SOC in JB to 50%
*charge to 100%
*deplete battery to 30%
*forget to update SOC next charge
*JB will assume SOC of 50%, and only deliver 30kwh... stopping you at 80% SOC

Set charge limit in the car, not the JB. Only use than app for viewing data.

Actually, I have a use case. It's not everyday, but common enough for me. I often travel for work, and the off-airport parking I use provides charging while parked there. Often enough, my car needs a slight charge the night before. Not a full charge, but enough to get me to the airport safely, so I can take full advantage of the included charging. In that case, I can set the time range on the juicebox to put in an hour or two of charging during non-peak time (post 11 PM for me), and I wake up in the morning with enough to get me to SFO, without wasting a portion of the benefit of the included charge.
 

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The EVSE is the power supply - both the stock (OEM) one that came with the car, as well as the JB. The "charger" is in the car (it converts AC power to DC).
Some other things to bear in mind: Peanuts, almonds, pistachios, cashews, horse chestnuts and pine nuts are not nuts. For example, peanuts are a legumes, so if you have a peanut allergy, you don't have a nut allergy but a legume allergy, and be sure to correct the bar tender about the bowl of “nuts” at the bar. Similarly, strawberries, blackberries and raspberries are not berries (botanically speaking), whereas a pomegranate is a berry, and so is a watermelon, a pumpkin, a cucumber, zucchini, a banana, an eggplant and a chili pepper. Also, a chimpanzee is not a monkey and neither is a bonobo.

If you care about technical correctness, these will all matter to you.

For most of us though, we know what someone means when they say “Level-2 charger” instead of “Level-2 electric vehicle supply equipment”.
 

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I too have a JB 40 and agree with wrillo. Let the car control/limit charging and set the JB to no limits. The Bolt has excellent scheduling/limiting capabilities built in and setting limits on the supply (EVSE) end is just asking for trouble. Like trying to figure out in the morning why the JB has decided to cut off the power prematurely and not allow the car to charge. BTDT.

A word of warning about the JB app: Any time you touch the top end arrow on their fancy dial, you're setting a 'per session kWh Charge Limit'. Based on your car's profile, this will always be at or below the car's nominal battery capacity. That all sounds great, unless the car needs more energy than that after it fully charges. Like if it's really cold outside and it wants to keep the battery from freezing. Or if you want to precondition in the morning on said -27C morning before your long trip. You can remove this limit on the web based dashboard by setting the Charging Limit to 0, but the moment you touch the arrow in the App, the limit is back. There is no way to clear that limit from the app. Yes I reported it to them. No they don't think it's worth fixing.

I like being able to see what the EVSE is doing in the app, but in hindsight I'd be fine with a dumb EVSE. Especially one where the cable didn't turn into a frozen garden hose when it gets cold out, the release button had some protection against water freezing under the release on the handle (such that you can't release it from the car), and one that didn't decide to shutdown at -30C because it thought it was overheating (app said the temp was 90C, clearly bad programming there).
 

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Discussion Starter #10
Thanks everyone for your thoughts and useful ideas. It's that fancy dial on the app that has me boggled.
Last night I set it to 57kW and it charged to that and as others have noted, did not taper, it just stopped.

So just now, I changed the fancy dial to 0->60 min/max and plugged it in. Since I'm already at 57k/W and using 95% in Bolt Energy Settings this shouldn't take long (it took 19 min). So the blinking green light is now solid green (which tells me the charge is done), but the JB is showing the charge light (maybe it shows that light anytime it is plugged in?), and my amperage has gone from 32A to 8A so that seems to be the Bolt tapering.

While typing this I received JB notification that charge is finished and app shows I added 1kW, which makes sense for my start of 57kW and Bolt limit of 95%. Chevy app shows 94% charge. My amperage is now at 0 and the JB charge light is now out. So I conclude that some form of tapering did occur, I probably need a longer charge to figure that out.
@JPT: I don't fully grasp your warning about the high end arrow. I made 2 changes since reading this thread and before plugging in. My fancy dial is now at 0 low and 60 top end (was at 57). I also enabled the Settings->Juice Net->'Min Charge' and set it to 60. My thinking is that if the JB wants to give 60 and the Bolt wants to receive 95% then this will work for 95% charge. It seems to me that the top end setting would be easy to accidentally change so I'll have to pay attention to that. Be curious to know what others think about using Min Charge of 60A, my app shows that "schedule has been overrode by Min Setting" and that is fine, I don't have a schedule. I figure that may force a full charge regardless of the high end arrow. Anyone know if that is true?
 

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...the blinking green light is now solid green (which tells me the charge is done), but the JB is showing the charge light (maybe it shows that light anytime it is plugged in?), and my amperage has gone from 32A to 8A so that seems to be the Bolt tapering.
The car can do "cell balancing" at the end of a charge cycle, which requires some current but not full current. I assume this is what you are seeing.
 

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He didn't say " “Level-2 electric vehicle supply equipment”. " - he said "I believe the OEM EVSE charger tapers the charge at the end of the cycle. The JB Pro seems to go to the desired charge setting I make and then stop, no tapering of charging current.
Do I need to be concerned about this?". I was emphasizing that it aint the thing outside (EVSE) that is tapering the charge, it's something inside the car.
 

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Discussion Starter #15
So as posted in msg #10 , I changed some app settings and plugged in again, it charged for 19 min (essentially topping off what I started prior evening that was inadvertently cut short by my improper app settings) and clarifies some of the questions I had that were answered in this thread; also useful for my understanding of the process.

In regards to tapering/balancing, attached is a screen shot from the app showing the charge over time. FWIW, the charge was done in a garage with a temp of around 50º F, the Bolt had not been driven for 16 hrs.
 

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No, it's most likely the car warming the battery after finishing the charge.
OK, I feel like I'm missing something here. Why would the car warm the battery after charging? Charging itself would warm the battery, so if it wasn't warming the battery before charging started I don't understand why it would start warming it afterwards....?
 

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OK, I feel like I'm missing something here. Why would the car warm the battery after charging? Charging itself would warm the battery, so if it wasn't warming the battery before charging started I don't understand why it would start warming it afterwards....?
This is precisely why it does it at the end. At the rate a Level-2 EVSE charges the car, a (moderately) cold battery isn't going to have a problem accepting the charge. So it charges the battery (which warms it a bit) and then warms it more if needed.

You can see this in graphs of charging from the JuiceBox, such as the blog post @GJETSON linked to, or the screenshot @jon8491 posted.
 

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Certainly, a more flexible system for charging is possible...one where you get to decide when to heat the battery. We know that the battery is happiest in the 70's F. We know that GM's priority was to make the whole system with nothing required from the driver. When you plug in the car, the system doesn't know if you actually plan to charge to full, or if you will leave early, etc. So job number one is to charge as hard as the battery temperature, and incoming power will allow. Job two is to raise the battery temperature to its happy place.

If there is enough incoming power, such as when DC fast charging, the car will charge as fast as battery temperature allows, and heat the battery at the same time. I saw just that behavior yesterday, at a free hotel fast charger. The day started warm and rainy, I had preconditioned for about ten minutes before heading out. Torque Pro showed both cabin heat and battery heat going. I left home with a "hilltop" charge, and drove around the countryside"washing" the car to get off the month's grime. By the time I had looped around, and came into Charlottesville with an extra 30 miles driven, the sun was out.

Check out the story and Torque Pro screen shots here.

https://endless-sphere.com/forums/viewtopic.php?f=34&t=75381&p=1441175#p1441175
 

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OK, I feel like I'm missing something here. Why would the car warm the battery after charging? Charging itself would warm the battery, so if it wasn't warming the battery before charging started I don't understand why it would start warming it afterwards....?
Indeed charging will increase the temperature some but it may not be enough to get the battery to where the car wants it to be.

In general the Bolt will only condition a battery (heating or cooling) if the car is turned "on" or if it's plugged into an EVSE and not charging (either charge complete or charge not needed). In my view this is a shortcoming of the Bolt's BMS, it should condition more than it does including during charging and when parked and turned "off".
 

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Certainly, a more flexible system for charging is possible...one where you get to decide when to heat the battery. We know that the battery is happiest in the 70's F. We know that GM's priority was to make the whole system with nothing required from the driver. When you plug in the car, the system doesn't know if you actually plan to charge to full, or if you will leave early, etc. So job number one is to charge as hard as the battery temperature, and incoming power will allow. Job two is to raise the battery temperature to its happy place.
IMO ideally the car should allow for maximum flexibility for the driver/owner when it comes to charging and conditioning. If that were the case it would all but eliminate the need to "smart" EVSEs like the JuiceBox. I think GM should have given the Bolt an "advanced" menu where drivers could make settings like "always condition the battery when needed".
 
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