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This is another really great video by Weber State, where Professor John D Kelly tears down the Bolt EV's high voltage system. He's even going to try to install DCFC on a Bolt EV that did not originally come with it.

A few tidbits that I've gleaned so far that I found particularly interesting:
  • The battery heater doesn't work during DC fast charging. It only activates during AC charging. Still, I think this is a feature GM should give owners some ability to activate.
  • The motor is limited 8800 rpm, which is likely where the 92 mph speed limiter comes into play.
  • The drive train has equal-length drive shafts (i.e., any torque steer experienced is purely the result of alignment and the tires).

 

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Very interesting video. Thanks for posting.
 

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Very interesting, thanks for passing it along!

  • The battery heater doesn't work during DC fast charging. It only activates during AC charging. Still, I think this is a feature GM should give owners some ability to activate.

  • This may be because fast charging heats the battery quickly enough on its own.
 

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the end of the video seem to say - NO DC charging will take place at all while cold --
You must get the battery warmer first via the other options.
 

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Having used a dcfc after a cold soak in the mid teens and a short 110 mile drive, it is slow to charge. It started at less than 20kw and ramped up to 24kw. Charged for over an hour with no increase beyond 24. Was in the 30-80 range of soc.
 

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Kelly has one of the coolest jobs on the planet. All his videos are very well done.
 

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Having used a dcfc after a cold soak ... it is slow to charge. It started at less than 20kw and ramped up to 24kw. Charged for over an hour with no increase beyond 24. Was in the 30-80 range of soc.
I saw similar performance during a test drive. I think the Bolt had been left out in the cold, unplugged, for days before I took it out.
Yes, you would think the act of Charging at 20-30kW would warm the battery in X amount of time, and then allow an increase of charge rate.

I'm waiting for this to be addressed and at the very least ACC in the next Gen Bolt before I get in the game.

My little Chevy BEV hits the batteries hard with 50kW every time I do a DCFC. But I guess I never arrive at one with a cold soaked battery.
 

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One of my favorite channels. His teardowns are extremely thorough and well-informed. Was hoping he would eventually do the Gen 2 Volt's 5ET50 to compare with Gen 1, but he "only" did the battery (which was also well-done).
 

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A few tidbits that I've gleaned so far that I found particularly interesting:
  • The battery heater doesn't work during DC fast charging. It only activates during AC charging. Still, I think this is a feature GM should give owners some ability to activate.

John has since corrected this info at the beginning of his latest video above...
 

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hope they cover soon getting the software working to support the DC charging after replacing the new charge port.
 
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