Chevrolet Bolt EV Forum

I called my dealer today and he located the DCFC upgrade after I gave him the # on the GM Bulletin andrew1joe posted .. { TY sir! }

https://allev.info/wp-content/uploads/2 ... NA-053.png

I was told: "It's covered under the car's warranty as long as you tell us you have a DCFC issue you would like fixed".

So, I said I did .. .. & that it was slow, especially on Electrify America units.

I have an appointment for the service free of charge on Monday.

UPDATE 5/4/20: All work was covered under warranty .. I presented a printout of the above bulletin and stated:

"When charging vehicle at public DCFC stations I'm getting Max 40-45kW. Vehicle manual states it should be achieving up to 75kW"

My dealer's service invoice reported: "Incorrect Communication - Programed HPCM2 as per bulletin 20-NA-053"


I haven't tested DCFC performance yet.

AJ

BoltEV wrote:I just tried an Electrify America 350Kw charger yesterday in Mojave and was disappointed to see a 34Kw charging rate on the dashboard when EVGo gives me 45!

Maybe I need this update for this problem as well.

If your traction battery temp is below 75°F, dc charge current will be restricted to less than the top restricted current, which is 150 amps. I use Torque Pro to view my vehicle's data (including battery temperature) https://youtu.be/LjqDk08x9EY

Sometimes EA stations are finicky or defective and won't give full speed. If my battery is warmer than 75 degrees, SOC is less than 55%, and I'm not receiving 150 amps at an EA site, I switch chargers if possible.

AyeJay wrote:The Bolt manual states our car will DCFC at "up to 75kW"..

AJ

I believe you're mistaken. The 2020 manual states, "When using a DC charging station
with at least 80 kW of available
power, it will take approximately
30 minutes to recharge from a
depleted battery to an estimated
145 km (90 mi) of driving range.
This time estimate is applicable to
nominal temperature ranges. In
extreme hot or cold conditions, this
time may be lengthened. A full
charge will take additional time."

Given proper conditions (traction battery temp >75°F), the top charge speed, as set by GM, is ~56kw, and will step down after ~55% SOC to around ~37kw(100amps), and then there are further step downs in charge speed, as the battery SOC increases.

Yeah .. I guess 75kW was wishful thinking on my part .. .. But hey, the dealer did the update for free!

The confusing part is that the manual does state: "When using a DC charging station with at least 80 kW of available power .." while the car's apparently limited to ~ 56kW?

I've read more than a few posts on various EV sites that find this Bolt manual's statement confusing, unclear and contradictory.

It has also been said the 20-NA-053 DCFC 'robustness' update improves the ability of the BMS to keep battery temps optimal.
This should improve ramping, consistency, possibly even increase the highest charging limit slightly.

I'm really wondering what the report of "Incorrect Communication" means on the invoice I received from the dealer following the update?

Will know more soon.

AJ

AyeJay wrote:The confusing part is that the manual mentions: "When using a DC charging station with at least 80 kW of available power" while they're limit is apparently at 56kW?

CCS 1 stations usually peak at 500 volts, so if the station is capable of 150 amp charging (the peak charging current permissible for the Bolt), that would likely label that station as a 75kw station (Why do they reference an 80kw station? See picture at bottom). Will any vehicles charge close anywhere near 75kw at said station? My guess is probably not. Why? Most EVs have a fully charged pack voltage of around 400 volts, but batteries aren't able to safely receive high levels of current at high SOC, so peak power will be reduced substantially, as voltages are lower at the lower SOC, when current is at its maximum. Even "outside the norm" EVs with higher pack voltages, like the MG ZS or the Porsche Taycan, or EVs with similar pack voltages, but higher current charging, such as the latest Hyundai/Kia products with 64kwh battery packs or the Audi eTron, won't charge much, if at all faster, than a Bolt, at a 75/80kw dc fast charger.

Owner's manuals, due to the nature of varying knowledge levels of the readers, can often be frustrating for providing either TMI or not enough, to satisfy.

All that being said, the charge rate of the Bolt EV is not what we'd like, but it is the best balance GM could COST EFFECTIVELY achieve. It was explained to my by a GM EV Team engineer, that different battery chemistries have different properties, and often, there are trade offs. In context of this particular conversion, with said engineer, I was criticizing and poking fun at how the Spark EV has had pretty significant battery degradation, but has wonderful power output and fast charge capability. He was disagreeable, yet fairly tight lipped, but pointed out that the Bolt battery pack has three times the energy, but only weighs twice as much as the Spark pack.

Sorry for the rambling, but hopefully that gave some food for thought.