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Discussion Starter · #1 ·
It’s my understanding that frequent dcfc isn’t great for battery longevity, but is there any increased fire risk to using it if your staying between 30% and 90% SOC?

just curious, I have a trip planned this weekend that is the first time since the recall that I can’t make a round trip in my 2020 without needing some charge to make it home above 30%. Should be able to make it with a 15 min dcfc session, but wondering if it’s more prudent to take a longer break and use L2. I’ve only used DCFC a handful of times in the 20k miles Ive put on this car and have generally kept SOC between 30% and 90% since mile zero.
 

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but is there any increased fire risk to using it if your staying between 30% and 90% SOC?
 

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Discussion Starter · #3 ·
thanks! I searched for a thread like this but didn’t find it. Operator error I guess.
 

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The overall fire risk is statistically very low (0.03%) but the consequences are high. I understand this. It can be made even lower by not 'routinely' charging to full and not 'routinely' discharging to < 30% (70 miles / 238 miles = 29.4%). Doing this occasionally raises your baseline risk by such a small amount as to be negligible. Fewer than 10% of my miles driven are on long trips requiring DCFC. For these 2-3x/year trips I do not hesitate to charge to full, or discharge to 10% (24 miles). GM has given little to no guidance on whether these fires occurred (at all) after AC Level 1 charging or DC Level 2 charging (DCFC). My plan is to concentrate on the word "routinely" and adjust my behavior accordingly. The "fix" is coming. Hang on Sloopy!
 

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The overall fire risk is statistically very low (0.03%) but the consequences are high. I understand this. It can be made even lower by not 'routinely' charging to full and not 'routinely' discharging to < 30% (70 miles / 238 miles = 29.4%). Doing this occasionally raises your baseline risk by such a small amount as to be negligible. Fewer than 10% of my miles driven are on long trips requiring DCFC. For these 2-3x/year trips I do not hesitate to charge to full, or discharge to 10% (24 miles). GM has given little to no guidance on whether these fires occurred (at all) after AC Level 1 charging or DC Level 2 charging (DCFC). My plan is to concentrate on the word "routinely" and adjust my behavior accordingly. The "fix" is coming. Hang on Sloopy!
Level 3 is dcfc...

Level 2 is still AC charging...
 

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Correct, there is no Level 3. As detailed in Wikipedia:

"As noted in Appendix M of the SAE J1772 standard document, a third AC charge method was also considered but never implemented. This AC Level 3 mode would have used up to 96 kW at a nominal voltage of 208–240 V AC and a maximum current of 400 A. There is no reference to a DC Level 3 charge method in the standard."

I had an EV that predated the J1772 standard that included an on board 480 VAC 3 phase capable charger somewhat like the proposed level 3. Not having access to such power, I never used it in that mode. In case your wondering, the EV was a 1994 Dodge TEVan with flooded nickel-cadmium batteries. It was so rare it should have been in a museum.
 

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What upcoming software update are you referring to?
The new diagnostics is supposed to do that, and slowly give you more range back if it thinks that your battery does not have the defect, until it's back at 100%. They are doing this at the same time they start replacing people's cells because the software will be way quicker to get everyone onto versus physically manufacturing all of the cells needed. It doesn't preclude still getting replacement cells even if it thinks you don't have the defect.

I loaded the calibration into my car that's detailed as being part of this last recall and I haven't seen any different behavior at all. (I've got a dealer tool and programming access for my VIN). I'm guessing there's something additional that's not been made available yet.
 

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Yeah, I'm still having a problem with KwH vs Kw vs any other capitalized letter...
What's helpful is to remember that the "smaller" metric prefix abbreviations are in lower case. They don't go all capital on you until you get to Mega- (M), for a million. Most unit abbreviations are in lower case, unless they were named after somebody. The Watt (for power units) was named after James Watt, in recognition of his greatly improving (not inventing) the steam engine.

Hence you get kW (kilowatts) as an abbreviation typically used for instantaneous electrical power, and kWh ( kilowatt-hours) as an abbreviation typically used for electrical energy (power over time).
 

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Do not trust references here, but do go to all the Bolt tech sites, as well as review the fires. You should find that the internal L2 charger, built into the Bolt, is the most suspect. Most real authorities are OKing L1 and DCFC. Though there is an L2 component in DCFC, it is reduced and most of the charge comes through the DC. I have seen advice to turn down your home AC L2 to 16a, and do your charging in sections, perhaps thirds, removing the AC in between. All that keeps heating and expansion to a minimum. I am not saying to do this, merely repeating what I have read. Oh yeah, however, I do the above with Bolts and even a Tesla Model 3.
 

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Just returned from a vacation to Panama City Beach, FL with my 2019 Chevy Bolt. When I left I charged the car to 100% and recharged five times with the GOM around 20 - 30 miles. Four times were at DCFC stations. No problems since I returned last Thursday. Normally I charge to 80% and never go below 50 - 60% charge level unless I’m traveling long distance.

Just as a precaution I have installed a smoke detector in my garage. I refuse to park the car outside when I have a two car garage. I have adjusted my charging to finish is most cases around 10 AM EDT.
 

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Doesn't seem to be any reports of using DC to charge that is causing the fires. It could be. My BMW i3 seemed to be affected by DC charging. I had free charging so I thought it was OK.
 

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L3 makes more sense than Direct Current Fast Charge. And everyone uses the term.

and the list goes on.
 
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