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Discussion Starter #1
I decided to do a video where I mapped out what we currently know of the Bolt EV's charge curve, and I shared my predictions on what we could possibly see when faster public charging is available.

 

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For me, irrelevant as I'll be charging 99.999%or maybe 100% in my garage.
 

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It will probably be irrelevant for most, but I have been approached by a number of people who want to know about the long-range viability of a Bolt EV. If it does charge at a significantly faster than what the current 125 A standard can provide, it would make the Bolt EV more competent for long trips. It's already capable with the current California infrastructure, but it would increase my average trip speed for my regular 500-mile runs by 5 mph or more.
 

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Great post, LB. I was skeptical at first about the Bolt charging being rated at 175 amps max, but you make a great case. One other clue might be if we hear that Chargepoint, EVGO, etc. are now installing/upgrading some of their more popular CCS charge stations in Bolt markets to 175A. I suspect GM would have confidentially-shared this information with the charger industry so they could efficiently plan how they build out their infrastructure.
 

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This article states an engineer said the Bolt's max DCFC rate is 60 kW.

If we assume the Bolt's battery pack voltage is around 360V at 50% SOC (just before the 1st taper), that suggests the Bolt can support ~165 amp current. 165 * 360 = 59.4 kW, very close to the 60 kW figure.
 

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For what it's worth, a GM manager told me earlier this year that the Bolt's peak rate on future chargers would be "a little more" than 50 kW and the peak charging current would be less than 160A and would be around 150A. At about the same time, Electrek published a positive Bolt EV review that gave a peak potential rate of 55 kW but did not attribute that information to any specific source.

We should finally know for sure in just a few more weeks.

I mentioned this in a new article published today:

http://www.hybridcars.com/vw-reveals-nationwide-ev-charging-plans/
 

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Discussion Starter #7
All information indicates that it will charge faster... it's just a matter of how much. Also, even using the numbers from the EVgo chargers themselves, the voltages varied by 1-2%. On one, peak charging rate occurred at 355 V, and on another at 365 V. Others have reported as high as 368-369 V. Brian's 360 V might be a good voltage to use for estimates.

Regardless, what I'm most happy about is that any battery conditioning and climate control seems to be drawn from excess power, which makes the effective charge rate 10-15 kW faster.
 

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It will probably be irrelevant for most, but I have been approached by a number of people who want to know about the long-range viability of a Bolt EV.
Understandable and thanks for posting. My comment was not on the value of fast charging, just that it will likely not matter to me one way or the other. Then again, I'd likely get the Bolt EV DC charging upgrade, just in case. :)
 

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Chevrolet normally does not make published claims that cannot be attained by owners, or exceeded.

When the Bolt EV was released, owners did not have access to more than 125 amp chargers. But not all chargers are 125 amps. So it was "Up to 90 miles in 30 minutes" when released.

This is how charging should be measured. Miles of charge in XX minutes. Peak charge rates in perfect conditions are not an accurate picture of what a new owner can expect. 120 kW Charging! tells you nothing unless it's 120 kW sustained.

And the final word on what a Chevrolet can do is not something a GM engineer should be telling you. They are supposed to stick to the 'official line' when it comes to specifications. A Chevrolet engineer told America that the 1998 Camaro Z28 put out 305 horsepower. This agreed with the brochure specs. The engineer knew that the engine was ~345 horsepower, but Chevrolet never changed the official numbers. Was the engineer lying? Eh... it put out 305 hp at 5600 rpm, but put out 345 hp at 6200 rpm. So he was and was not telling the truth.
 

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Discussion Starter #10
I, too, am a much bigger fan of providing average charge rates. The peak numbers are good as a sales pitch, but people want to know about how much power (or range) they will get if they plug in for 15, 30, 60 minutes, etc.
 

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I, too, am a much bigger fan of providing average charge rates. The peak numbers are good as a sales pitch, but people want to know about how much power (or range) they will get if they plug in for 15, 30, 60 minutes, etc.
The problem is that it's not that simple. What you get in 15, 30, etc minutes depends greatly on the starting SoC. Here're some graphs from my slightly optimistic battery model. See the bottom one to see how much range you get in 30min. (The flat line from 92 to 100% is an error, it should be linear to zero at 100%.)

 

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All information indicates that it will charge faster...
While I'm pretty confident that we'll discover that the Bolt will charge faster when someone is able to hook it up to a charger with a higher power rating, we should keep our expectations realistic. The higher charge rate will only be realized at lower battery states of charge, and if it tops out at 60KW then it's only 20% more than what current chargers are capable of. You have to combine that with the fact that few people traveling long distances will arrive at a charger with 0% in the battery, because the charger may be out of service or in use - so you have to keep some "Plan B" charge in reserve.

When you combine all these factors, you're probably looking at 10% or less improvement in charge times to the 80% state of charge level, which translates to about 6 minutes over an hour. Yeah, it's nice if it charges that little bit faster but it's not going to change anyone's opinion of whether or not it's fast enough for them.
 

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Discussion Starter #13
While I'm pretty confident that we'll discover that the Bolt will charge faster when someone is able to hook it up to a charger with a higher power rating, we should keep our expectations realistic. The higher charge rate will only be realized at lower battery states of charge, and if it tops out at 60KW then it's only 20% more than what current chargers are capable of. You have to combine that with the fact that few people traveling long distances will arrive at a charger with 0% in the battery, because the charger may be out of service or in use - so you have to keep some "Plan B" charge in reserve.

When you combine all these factors, you're probably looking at 10% or less improvement in charge times to the 80% state of charge level, which translates to about 6 minutes over an hour. Yeah, it's nice if it charges that little bit faster but it's not going to change anyone's opinion of whether or not it's fast enough for them.
If the peak is 60 kW, that's actually 33% faster than the best we can currently achieve. Maybe I'm just a risk taker, but I've been more than comfortable with arriving at DCFC stations with 5-10% SOC. Even if you are super conservative, 20% SOC should give you more than enough buffer. And that would still result in a fairly impressive improvement over current charge rates (close to 25% faster).

The main thing I'm looking forward to is the advantages of the surplus power while charging in summer and winter.
 
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