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Discussion Starter · #1 ·
I live in rural Arkansas, and the first CCS station within reasonable driving range just opened up, with 4 350 KW CCS plugs, 3 150 KW CCS plugs, and 1 50 KW CHAdeMO plug.

Starting with 53% SOC when I plugged in it started off with 54.46 KW charging rate, and about 35 min later sent me a text saying I was at 80% SOC. By the time I walked back to my car from shopping, I had been charging for 42 min, and was at 85% SOC and the charge rate was down to 18 KW. Over all I received 22 KW in 42 min, for an average over the charging session of 31.4 KW. I know that starting from a lower SOC would have gotten me a better average charge rate.

Anyone have charts for charge rate on a high power CCS (350 KW or 150 KW) made from real world data yet? I am curious about the charge rate vs SOC for the high power units.

Later,

Keith
 

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The Bolt charges at a max of ~150A on DCFC. If battery voltage is 340V, then total power : 340*150=51kW.

The vehicle seems to max out around 55 kW, and then it very quickly steps down to around 37 kW (at around 50-55% SoC).
 

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The Bolt EV's charging profile does vary based on conditions, and it appears that GM programmed a cell leveling protocol to balance cells while DCFC. These are my observations so far for the Bolt EV's max charging current:

0-51% (sometimes 55%): 150 A
55% to 68% (varies a bit as well): 105 to 110 A (this is where the cell balancing appears to occur)
68% to 85%: 68 A
85% to 95%: ~40 A
 

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So you are watching this on Torque Pro? For cell balancing to occur, they would need to be holding voltage steady. Is this what you are seeing?
Yes, it is on torque pro. If the overall charge voltage has to be constant for cell balancing, then no. But it does appear that individual cells are getting more or less current depending on their cell-level voltage. For instance, I have approximately 10 cell groups that are consistently .01 V lower than all of the other cell groups; however, during this phase, they can reach parity or drop to as much as .02 V lower than the other cell groups.

Whatever is going on during that phase of the charge curve, it looks different than the other phases of the charge curve.
 

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Yes, it is on torque pro. If the overall charge voltage has to be constant for cell balancing, then no. But it does appear that individual cells are getting more or less current depending on their cell-level voltage. For instance, I have approximately 10 cell groups that are consistently .01 V lower than all of the other cell groups; however, during this phase, they can reach parity or drop to as much as .02 V lower than the other cell groups.

Whatever is going on during that phase of the charge curve, it looks different than the other phases of the charge curve.
I would be amazed if GM was actively balancing cells at anywhere other than full charge. It would require, basically, another complete BMS.

If this is actually a group of ten cells you are looking at, it may be a complete module. The cells are arranged:

cells 1-10, module #1 , temp thermistor #1
cells 11-20, module #2 , temp thermistor #2
cells 21-30, module #3 , no temp thermistor
cells 31-40, module #4 , no temp thermistor
cells 41-48, module #5 , temp thermistor #3 (module #5 has only 8 cells)
cells 49-58, module #6 , temp thermistor #4
cells 59-66, module #7 , no temp thermistor (module #7 has only 8 cells)
cells 67-76, module #8 , temp thermistor #5
cells 77-86m module #9 , no temp thermistor
cells 87-96, module #10, temp thermistor #6

Module #5 and module #6 are up under the rear seat. When the car sits for a period of time, without coolant circulation, you will see these two modules sit at a higher temp than the others. During coolant circulation this is not the case. Then, modules #1 and #10 are often the hottest.
 

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Discussion Starter · #9 · (Edited)
The Bolt EV's charging profile does vary based on conditions, and it appears that GM programmed a cell leveling protocol to balance cells while DCFC. These are my observations so far for the Bolt EV's max charging current:

0-51% (sometimes 55%): 150 A
55% to 68% (varies a bit as well): 105 to 110 A (this is where the cell balancing appears to occur)
68% to 85%: 68 A
85% to 95%: ~40 A
Here are my results:
0% to 49% fluctuating between 144 and 152 amps, average 148 amps.
49% to 66% fluctuating between 102 and 112 amps, average 108 amps.
66% to 81% fluctuating between 62 and 70 amps, average 66 amps.
81% to 91% fluctuating between 41 and 49 amps, average 45 amps.
91% to 95% fluctuating between 26 and 34 amps, average 30 amps.
95% to 100% gradual sloped drop in amps (with fluctuations) from 30 amps down to 10 amps.

Here is a link to my charging from 3% to 100% on the 350 KW charger with a bunch of graphs made from my torque pro app data.

https://www.chevybolt.org/forum/82-charging-batteries/29689-first-full-charge-3-100-a.html

Later,

Keith

PS: Obviously your beginning SOC and probably battery temperature and several other factors play a part in adjusting these curves, or I would not have started my first charging session at 54.4 KW... following my chart it should only have been charging at 40ish KW at that point. Charging may have fallen off rapidly on that charge, I didn't have torque pro set up yet, and went in to shop rather than watching the car charge.
 
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