[bro1999]

This time, I decided to do a quick test of a 125 amp DCFC Chargepoint station as my 2nd attempt at fast charging. Being a 125A CP station instead of the 100A EVgo station I got raped at with a slow (<35 kW) charge rate, and a properly heated HV battery, I would surely experience much faster charging speeds, right?? Ehhhhhhhhhh......

I drove out to the CP station that is ~16 miles from my house. Temps were in the upper 30's, but this time I tried to make sure the battery was heated up properly, and I ended up doing a half dozen 50-70 mph "floor it" runs, trying to heat the battery to a higher temp than last time. I'm not sure what the HV battery temperature was, but it had to be higher than my first time fast charging.

I arrived at the station with a 45% SOC, plugged in, and here were the results. I only was able to charge 15 minutes because the liquor stores were closing, and I had to "Bolt" to the nearest one to get booze for the night.

Here are the snapshot stats:
1 minute in: 22.1 kW
6 minutes: 25 kW
10 minutes: 28.1 kW
16 minutes: 35 kW
Beginning SOC%: 45
End SOC%: 54

Total of 7 kWh charged in ~16 minutes. It is 29 cents/kWh, but there was a $3.50 minimum charge, so since I had to leave early, I didn't get my money's worth. Still way cheaper than EVgo though. Didn't sniff ~44-45 kW, which I figured would be the max charge rate at a 125A station.

I have to add, driving back was very fun. Had to take some local roads, so the Bolt was getting slung into some twisty turns without any issues!

 

[Ladogaboy]

That's an interesting ramp up time. I haven't experienced that with any of my DCFC experiences. The ChargePoint 24 kW stations immediately ramped up to 24 kW, and the EVgo stations were at 100 or 125 A within a matter of seconds.

 

[BAZINGA]

How long would it have taken to fully charge?

 

[robmich]

How long would it have taken to fully charge?

I guess I should have taken a pic, but my first charge experience at an EVGO site was good. I received 47-49 kW up to 80 % and 24 kW till 90% when I stopped it.

Rob

 

[Bacardi]

Thanks for sharing...Once we get some more DCFC datapoints we'll learn more about ramp up...One relatively concerning thing is if a colder battery does indeed make a big difference whether this is more of an issue on the Bolt or all EVs...You'd imagine the primary customer of the Bolt EV is more concerned with efficiency vs let's go with AutoX lap times...You had to do some WOT runs to heat up the battery which could case some unfavorable bolt stats to those concerned with efficiency...Also as noted, DCFC's are popping up more and more with hard time limits, Bro noted on his first charge is 30mins...Again with more datapoints if we determine a cold battery is an issue, wonder in the future if all EVs should of sort of pre-charge battery heater?

 

[Chris TX]

Maybe this is why Chevy isn't really listing any official specs for L3 charging, for the Bolt. That kind of ramp up and limitation is too conservative, in my opinion. I would be curious to see a 5% SoC charge up to 80-100%. Before these things were delivered, the 50-80kW CCS charging was being thrown around. This is terrible.

 

[mpmoore1979]

The system most likely uses the Outside Air Tem (oat) reading instead of the battery temp sensors to manage the battery input and out put. I had a Volt the other day that the ambient temp sensor (oat) was unplugged and the temp display was reading -40 so when I ran the car I got the ERDTT warning and the engine started and the ambient temp was 72 degs out so the battery was up to temp. Also noticed in the summer if I have may car (2015 volt) inside the shop where its 75 degs, the ambient temp reading 75 degs the hvac on reads around 35%. Driving home and within 1 mile as the ambient temp climes over 100 degs, the hvac climes as well to over 70% at the same rate of clime. The battery is not getting hotter, just the ambient temp so the system reacts to the OAT rather then the battery temp sensors.

 

[Ladogaboy]

I guess I should have taken a pic, but my first charge experience at an EVGO site was good. I received 47-49 kW up to 80 % and 24 kW till 90% when I stopped it.

Rob

Yeah. Those have been my experiences as well. It sounds like Brian has a bunch of dud charging stations in his area.

Maybe this is why Chevy isn't really listing any official specs for L3 charging, for the Bolt. That kind of ramp up and limitation is too conservative, in my opinion. I would be curious to see a 5% SoC charge up to 80-100%. Before these things were delivered, the 50-80kW CCS charging was being thrown around. This is terrible.

Well, this isn't on Chevy, unless it is Brian's car specifically. Based on my experiences, the Bolt EV is exceeding the current charging infrastructure capabilities, not the other way around.

 

[Norton]

..... It sounds like Brian has a bunch of dud charging stations in his area.
...Well, this isn't on Chevy, unless it is Brian's car specifically. ....

Dang, how could Bro squawk this to Chevy and have them take him seriously?
Plus the local dealers may not be tooled up yet for the Bolt.

I know with my lowly Spark EV those 50kW Efacec stations give me a rock solid 48kW display in <1 min of starting.
Chargepoint is just the network.

 

[PH2]

The charging process most definitely uses the battery pack's internal thermometers, as this can vary drastically from OAT; it would be extremely hazardous otherwise. Climate control functions operate more on OAT.
How long was your Bolt cold-soaking before you went on your trip? EV's that do not aggressively manage the battery's temp through active TMS (i.e. Tesla) slow down their charge rates on regen and L3 until the battery warms up. I would be willing to bet that the 'runs' did not heat up the battery as much as you think; after cold soaking my EV (battery temp probably in the upper30's/low 40's) it took about 11 miles of driving with the 6kW heater full blast before the regen limited warning disappeared. Even after this, regen was still restricted for the next 10 miles and half of the trip was at interstate speeds. It takes a lot of energy/time to change the temp of a ~400lb chunk of metal, plastic and water 10-20 degrees.
L3 charging through JdeMo is limited below 51 degrees F IIRC; lithium batteries are not recommended to be fast charged at all at low temps (~41F), or charged period below 32 degrees F. See http://www.batteryuniversity.com/learn/article/charging_at_high_and_low_temperatures I would bet that the Bolt follows similar protocols; Tesla addresses this by keeping the pack warm at the cost of range as long as the SOC remains above a certain threshold.
The only other consideration I can think of is perhaps the station's output was limited; I know that sometimes this happens when station owners and the utility company have to come to a compromise on the instant demand on the grid; this can also be remotely limited at times of peak demand for some stations and is in fact a feature on the Volt.
Also, L3 output is highly dependent upon the EV's max battery voltage. Full power from a L3 station is only realized between 400-500 volts for higher power stations/next generation IIRC, so most production EV's with ~320-380 volts packs peak the station at around 40-48kW; max L3 charger output in kW = Pack's max voltage x 125 amps (50kW station). Although this isn't what you are experiencing, you probably won't realize the full potential of the L3 station in the Bolt (350V nominal).

 

[Ladogaboy]

Dang, how could Bro squawk this to Chevy and have them take him seriously?
Plus the local dealers may not be tooled up yet for the Bolt.

I know with my lowly Spark EV those 50kW Efacec stations give me a rock solid 48kW display in <1 min of starting.
Chargepoint is just the network.

Maryland dealerships should be authorized to start selling Bolt EVs soon. Maybe some of them already have diagnostic tools available.

I think he should try and coordinate with another Bolt EV owner, go to the same DCFC charger, and see if the experiences differ.

 

[Norton]

.....
The only other consideration I can think of is perhaps the station's output was limited; I know that sometimes this happens when station owners and the utility company have to come to a compromise on the instant demand on the grid; this can also be remotely limited at times of peak demand for some stations and is in fact a feature on the Volt.....

I never heard of this feature before on any EV.
Wouldn't the EVSE have to have a network connection to the local Grid supplier and then the EVSE changes the pilot signal to the Volt's OBC?

What other communication method could possibly do what you stated above? I don't think Onstar communicates this info.

References?

 

[jsmay311]

This lack of charging performance in even moderately cold temps is very surprising and disappointing.

Having a 16 mile drive before arriving at the station should give the battery heater plenty of time to warm the battery to a comfortable temp (even absent driving it hard on purpose to "artificially" raise the battery temp).

And even if the "while driving" battery temperature targets are too low for decent DCFC charging rates, then 16 minutes plugged into the DCFC should be enough to warm the battery up enough for full charge rates. (Or is it already tapering at only 57% SOC?)

This is not a good sign. Maybe a more powerful battery heater is needed.

Hopefully someone can come up with a chart of battery temperatures vs battery heater settings vs charge rate limitations.

The system most likely uses the Outside Air Tem (oat) reading instead of the battery temp sensors to manage the battery input and out put.

As PH2 already pointed out: no, no, no... a thousand times no.

 

[Ladogaboy]

This lack of charging performance in even moderately cold temps is very surprising and disappointing.

Again, this in no way reflects my experiences DCFC even down to the mid 30s F. Now, my experiences are also based on having driven ~160 miles in those conditions and then plugging in, but those should be the only times you would really be relying on DCFC anyway.

 

[RobbertPatrison]

I would say that DCFC is useful, but at 29 cents/kwh, it is expensive....

It means about 8 cents per mile energy cost for the Bolt.
The Volt2 on gasoline is 5.3 cents/mile (EPA numbers and average gas price).

 

[PH2]

.....
The only other consideration I can think of is perhaps the station's output was limited; I know that sometimes this happens when station owners and the utility company have to come to a compromise on the instant demand on the grid; this can also be remotely limited at times of peak demand for some stations and is in fact a feature on the Volt.....

I never heard of this feature before on any EV.
Wouldn't the EVSE have to have a network connection to the local Grid supplier and then the EVSE changes the pilot signal to the Volt's OBC?

What other communication method could possibly do what you stated above? I don't think Onstar communicates this info.

References?

Certainly, page 9-52 and 9-55 of the 2013 Volt Owner Manual; and yes it can be done through Onstar.

 

[jsmay311]

Again, this in no way reflects my experiences DCFC even down to the mid 30s F. Now, my experiences are also based on having driven ~160 miles in those conditions and then plugging in, but those should be the only times you would really be relying on DCFC anyway.

I live near Chicago and have family in Decatur, IL and Champaign, IL (each ~150-160 miles away) that I visit each at least once each for Christmas and Thanksgiving (when it's cold). If making that trip in a Bolt or similar (215+ mile) EV, I would be able to make the one-way trip without charging. Then the battery would cold soak for 6-24 hours and I would want to charge early on during the return trip when the battery is still cold.

If I had to change my schedule around to plan for a charging session BEFORE arriving at my relatives' house just because the car charges slow while cold and can't warm up the battery in a reasonable time, that would be a pain in the arse, IMO.

(Would anyone disagree that it would be more annoying to have to charge BEFORE arriving at a destination to take advantage of the battery heat rather than charging during the return trip?)

 

[PH2]

This lack of charging performance in even moderately cold temps is very surprising and disappointing.

Again, this in no way reflects my experiences DCFC even down to the mid 30s F. Now, my experiences are also based on having driven ~160 miles in those conditions and then plugging in, but those should be the only times you would really be relying on DCFC anyway.

Yes, I would only see this happening after a long cold soak for the battery or negative overnight temps. I went on a >350 mile trip recently and charged 3 different times on L3 at max rate when the OAT was ~35F, but the car stayed plugged in at my destination on L1 so the pack stayed warm.
I only experienced the limited regeneration due to battery temperature when the car sat unused for for a couple days with temps between 30F and 50F. People report this with the Volt in colder regions, only they get a indication to plug in to warm the pack and the ICE kicks on.

 

[Ladogaboy]

Certainly, page 9-52 and 9-55 of the 2013 Volt Owner Manual; and yes it can be done through Onstar.

I think he was referring to charging stations throttling based on a schedule. That would make no sense as they are proving a public service, and they should be providing the stated rates at all times.

I live near Chicago and have family in Decatur, IL and Champaign, IL (each ~150-160 miles away) that I visit each at least once each for Christmas and Thanksgiving (when it's cold). If making that trip in a Bolt or similar (215+ mile) EV, I would be able to make the one-way trip without charging. Then the battery would cold soak for 6-24 hours and I would want to charge early on during the return trip when the battery is still cold.

If I had to change my schedule around to plan for a charging session BEFORE arriving at my relatives' house just because the car charges slow while cold and can't warm up the battery in a reasonable time, that would be a pain in the arse, IMO.

(Would anyone disagree that it would be more annoying to have to charge BEFORE arriving at a destination to take advantage of the battery heat rather than charging during the return trip?)

It would be, but why is that you're only option? No charging onsite? Regardless, I'd want to identify whether bro's experiences are an anomaly first. A 6 kW resistance heater should heat the battery very quickly, and I would be surprised if it added even 5 minutes to the recharge time on a > 50 kW charger.

I only experienced the limited regeneration due to battery temperature when the car sat unused for for a couple days with temps between 30F and 50F. People report this with the Volt in colder regions, only they get a indication to plug in to warm the pack and the ICE kicks on.

You've already experienced limited regeneration in the Bolt EV?

 

[PH2]

Certainly, page 9-52 and 9-55 of the 2013 Volt Owner Manual; and yes it can be done through Onstar.

I think he was referring to charging stations throttling based on a schedule. That would make no sense as they are proving a public service, and they should be providing the stated rates at all times.

I don't see how you've inferred this from the post. Have you never had a utility 'throttle' a service before? Electricity is just as much a limited resource as water, cellular data, etc. We are talking about dumping an instantaneous power (kW, not kWh) equivalent of what 25 average US houses draw into a car for a one hour period, so yes it seems reasonable for a need to control this at peak times. I've never seen a station post you would get a rate of 'x', as there are far to many variables; but I concede I haven't seen them all...

And no I havent observed limited regeneration in a Bolt (as I don't own one), but I have in a Volt and Rav4EV. Regen rates in both can exceed the power rating of most L3 CCS/CHAdeMO chargers.