The 30 minute session resulted in ~22.5 kWh, or an average charge rate of 45 kW. Unfortunately, I was unable to get my OBD2 adapter to work and log the charge.

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The 30 minute session resulted in ~22.5 kWh, or an average charge rate of 45 kW. Unfortunately, I was unable to get my OBD2 adapter to work and log the charge.

Thanks for catching the typo.

As for the charging speed, I actually disagree. I have a hard time believing that GM limited the max current to 125 A, especially because we have video footage of them testing the Bolt EV on a 175 A charger. I've built out a couple of predictive models of the Bolt EV's charge curve, and one of them almost identically matches with pretty much everything that GM has publicly stated regarding the charge rate (i.e., 50 kW average charge rate to 80%, 60 kW peak rate, 80 kW charger required for max charge speed).

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Thanks for doing all this analysis in the interest of science. Most of us would just plug it in and drive.Thanks for catching the typo.

As for the charging speed, I actually disagree. I have a hard time believing that GM limited the max current to 125 A, especially because we have video footage of them testing the Bolt EV on a 175 A charger. I've built out a couple of predictive models of the Bolt EV's charge curve, and one of them almost identically matches with pretty much everything that GM has publicly stated regarding the charge rate (i.e., 50 kW average charge rate to 80%, 60 kW peak rate, 80 kW charger required for max charge speed).

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Sorry for the basic questions, but I am realizing I know less about chargers than I thought I did.

I have always thought of chargers by their kW charge rate, i.e. my Volt tops out at 3.3 kW charging, but there are 22 kW chargers out there for BEV's and many of us are now hoping for DCFC at 75 kW chargers in an area near you. Next year, or the year after, maybe 150 kW charging will start to show up...

My Model S can, with the CHAdeMO adapter. I did it several times on a trip from TX to TN. I even charged at Nissan's US HQ, at that rate. It's all about the voltage.

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I really doubt your Tesla can charge at 50 kW at a *100 AMP* station. Unless your Tesla is special and has a nominal 500 volt battery.My Model S can, with the CHAdeMO adapter. I did it several times on a trip from TX to TN. I even charged at Nissan's US HQ, at that rate. It's all about the voltage.

But if that's the case (max charging capped at 125 amps), why does the Bolt's manual quote using an 80 kW DCFC station? If the Bolt can attain the "90 miles in 30 minutes" at a 50 kW station?

Anyways, I have sources that tell me if the Bolt is plugged into a >125 amp station, the Bolt can take advantage of that extra juice.

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It's just as likely that they simply quoted rates achievable on the chargers actually available to the public. It would have been pretty bad publicity for them to quote charging rates that nobody could actually achieve in practice due to a lack of capable chargers.They might have validated the hardware for higher rates, but they may have software-limited the current model year to 125A.

We're not going to know for sure one way or the other until someone's able to charge at a charger with a substantially higher capacity than 125A.

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If the original Model S 60 is any indication I too think the Bolt EV at about 20% SOC will take 175A and possibly 200A for a short period of time before tapering. We will know soon enough as Ampera-e's will be delivered in Norway very soon and they have 100KW 200A CCS units there. The Bolt EV manual does state a maximum charge rate of 80KW.

A station with a 50KW name plate rating will either mean 50KW at 500VDC and 100A (Power (KW)/1000 = Voltage (V) X Current (A)). Or it will mean 400VDC at 125A.

Sorry for the basic questions, but I am realizing I know less about chargers than I thought I did.

I have always thought of chargers by their kW charge rate, i.e. my Volt tops out at 3.3 kW charging, but there are 22 kW chargers out there for BEV's and many of us are now hoping for DCFC at 75 kW chargers in an area near you. Next year, or the year after, maybe 150 kW charging will start to show up...

The Bolt EV has a nominal pack voltage of 344VDC. So it's charge voltages are below 400VDC. So even if you charge at the station maximum of 125A you will not hit 50KW due to the lower charge voltage. Currently there are no BEV's on the market that charge above 400VDC (that use CCS or CHAdeMO). Though there are some planned.

However looking at the charge curve the Bolt EV maxes out a 125A charger from 5% to ~55% SOC. This would seem to indicate that the Bolt EV can handle even higher charge currents in the 5% to 40% SOC range.

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I think I have read that a time or two on various sites but it never seems to stay in memory. And 344 volt limit explains why the Bolt isn't charging at or closer to the rated 50 kW on a 125 amp charger.

Thanks again!

Hmm...that seems odd. For a 39% increase, I'd expect to see more than 22 kWh. 22 kWh isn't 39% of the known net battery capacity (60 kWh) or of the estimated gross battery capacity (~64 kWh).I did a 30 minute charge at an EVGo 125A/50 kW station and went from 21% SOC to 60%. Station delivered 22 kW in that 30 minutes. 76 miles of estimated range was added:

View attachment 133130 View attachment 133138 View attachment 133146 View attachment 133154

It's unclear if the SOC % reported by the station is the raw or the usable part of the battery. I'm guessing it's the usable portion. I didn't think to check in the myChevrolet app what the reported capacity was before and after charging. If I get a chance to repeat the experiment, I'll also be sure to bring my OBDII reader as well to pull more data.Hmm...that seems odd. For a 39% increase, I'd expect to see more than 22 kWh. 22 kWh isn't 39% of the known net battery capacity (60 kWh) or of the estimated gross battery capacity (~64 kWh).

There is no 344V limit. Neromanceres said that the "nominal" or median pack voltage is 344V but I'm not sure where that number came from since GM's SAE papers say 350V. That voltage is also the "open circuit" voltage when the battery is resting and unused. The voltage during charging will be somewhat higher as the charger is pushing energy into the pack.

I think I have read that a time or two on various sites but it never seems to stay in memory. And 344 volt limit explains why the Bolt isn't charging at or closer to the rated 50 kW on a 125 amp charger.

Thanks again!

All signs I've seen so far point toward a peak charging rate of 55-60 kW at a peak charging current of around 150A. It shouldn't be too much longer before we find out. The Ampera-e is beginning to arrive in Norway and there is at least one 200A CCS charger there. Public CCS chargers at 200+ amps are scheduled to be available in the US in another 2-3 months.

When the Bolt is fully charged, the pack voltage is at ~400 volts. When it is nearly depleted (10% SOC) it sits around 330 volts. So a nearly depleted pack can start charging at ~41 kW on a 125A charger assuming the pack is fully warmed up. If it isn't fully warmed up, the car may request that that charger throttle back the Amps so it might only deliver 100A which would be 33 kW of power. At 50% SOC, pack voltage is around 360 volts for 45 kW. The highest kW that people have seen is 46, which implies that pack voltage is around 368 volts and tapering is about to begin because the car has reached ~60% SOC.

I think I have read that a time or two on various sites but it never seems to stay in memory. And 344 volt limit explains why the Bolt isn't charging at or closer to the rated 50 kW on a 125 amp charger.

Thanks again!

A crude calculation I've come up with is that for every 1 Volt rise in voltage, SOC goes up by about 1.33 %.

I thought that originally, too. But when I looked closer at the numbers, it appears to be gross battery capacity. I just did another session where the tower reported 44% at start of charge and 72% at end of charge (a 28% percent increase) with 18 kWh charged (28% of a 64 kWh battery).It's unclear if the SOC % reported by the station is the raw or the usable part of the battery. I'm guessing it's the usable portion. I didn't think to check in the myChevrolet app what the reported capacity was before and after charging. If I get a chance to repeat the experiment, I'll also be sure to bring my OBDII reader as well to pull more data.

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