[devbolt]

A poster on the Norwegian Electric Vehicle forum https://elbilforum.no/forum/ plugged into a 100 kW capable charger and reported the following:

(translation via translate.google.com):

Turned me a walk past tonight to test.
The charger showed the following values:
7% SOC 52.6kW
11% SOC 53.7kW
21% SOC 53.8kW
33% SOC 54.6kW
44% SOC 55.2kW
49% SOC 55.5kW

The circulation pump for BMS started quite early, after which also started the A / C compressor and fan which then went too far. Then it was between 3-4kW for that.

It adjusted the charge in what it reached 50% SOC, and it was a little strange that it then went down to the same level as I previously experienced at 57% SOC, about 37kW. It may seem that the temperature in the battery might be the limitation. By quitting the charge and leaving the battery "rest", I gained "full" speed again for a while when I reconnected.

Without the opportunity to see the charging voltage, I assume that the maximum current the car accepts is 150A

Translated post is available at:
https://translate.googleusercontent...bo47c2&usg=ALkJrhjgrh-qAMKw80K3QCq0gJp2Aq4xTQ

Go to page 14 of the thread, and then scroll most of the way down for the post.

I suspect that the Bolt is actually pulling upwards of 160A at low SOC because I've seen pack voltage as low as 341 volts at around 11%. 53.7 kW / 341V = 157.4A.

 

[bro1999]

A poster on the Norwegian Electric Vehicle forum https://elbilforum.no/forum/ plugged into a 100 kW capable charger and reported the following:

(translation via translate.google.com):



Translated post is available at:
https://translate.googleusercontent...bo47c2&usg=ALkJrhjgrh-qAMKw80K3QCq0gJp2Aq4xTQ

Go to page 14 of the thread, and then scroll most of the way down for the post.

I suspect that the Bolt is actually pulling upwards of 160A at low SOC because I've seen pack voltage as low as 341 volts at around 11%. 53.7 kW / 341V = 157.4A.

Some guy on FB now owes me $100 for betting there was NO WAY the Bolt could charge faster than 50 kW/125A.

 

[Taser54]

A poster on the Norwegian Electric Vehicle forum https://elbilforum.no/forum/ plugged into a 100 kW capable charger and reported the following:

(translation via translate.google.com):



Translated post is available at:
https://translate.googleusercontent...bo47c2&usg=ALkJrhjgrh-qAMKw80K3QCq0gJp2Aq4xTQ

Go to page 14 of the thread, and then scroll most of the way down for the post.

I suspect that the Bolt is actually pulling upwards of 160A at low SOC because I've seen pack voltage as low as 341 volts at around 11%. 53.7 kW / 341V = 157.4A.

Software limited at this point. It will be interesting to see when GM unlocks it to take advantage of these higher power charging stations.

 

[bro1999]

Software limited at this point. It will be interesting to see when GM unlocks it to take advantage of these higher power charging stations.

From the "Some guy on Facebook" sourcing, it was stated that it's the belief the Bolt's fast charging hardware was rated to take up to 200A. Not sure if that is the theoretical maximum that is never reached in the real world (similar to running wire for 25 amps and installing a 20A max EVSE to give the 20% buffer) and that 160A is the max real world amp limit.

 

[Neromanceres]

From the "Some guy on Facebook" sourcing, it was stated that it's the belief the Bolt's fast charging hardware was rated to take up to 200A. Not sure if that is the theoretical maximum that is never reached in the real world (similar to running wire for 25 amps and installing a 20A max EVSE to give the 20% buffer) and that 160A is the max real world amp limit.

I'm going to the GM silent cruise in Detroit tomorrow. I'm going to talk to some of the engineers there to see what details I can get with this new information.

 

[CCIE]

I'm fairly certain I saw somewhere that the wire size from the Bolt's CCS inlet precluded anything over 60 kw. I'll have to see if I can dig up the reference.

 

[Qinsp]

I'm fairly certain I saw somewhere that the wire size from the Bolt's CCS inlet precluded anything over 60 kw. I'll have to see if I can dig up the reference.

The MGU (generator/motor) does have enough copper to handle 70kW of monitored charging (regen). The battery is wired to a minimum of 150kW to the MGU motor side.

Unless there is weak link in the actual CCS car-side conductors, it's unlikely to be under 70kW. It is interesting to note the OM says 80kW is required for the quickest charge rate. Assuming they mean At The Wall, the car is probably wired at 70-150kW depending on the circuit.

Was the Norway Test optimum conditions? It appears to still be climbing at 55.5kW which means it's not seeing a ramp rate that would require reduction in load yet. Due to the delay in reported data from sensors, it needs to cut current while it is still ramping up.

From early on, I've been betting it's 60kW or higher due to how low a 1 C charge rate is to a modern battery, and the 70kW regen. But I also said cooling a car that is not moving sucks. There is the problem with charging EVs. No amount of heat exchangers and electric on-board fans are going to match driving at 35 mph.

 

[hvacman]

Tesla says the Model 3 base version (220 mile range) will charge 130 miles in 30 minutes, which is about 60 kw. The Bolt (238 mile range), at a 55 kW-charge rate for the first 50%, will charge about 110 miles in 30 minutes (as opposed to 90 miles with 45 kW charge rate from 125-amp CCS chargers). Given GM's propensity to error on the side of safety and longevity regarding battery engineering as opposed to Tesla's more aggressive, risk-taking approach, I'll take that slightly slower charge-rate in a heart beat.

Those that slam GM for engineering a "slow-charging" BEV as compared to the prowess of the Tesla Model 3's charging speed need to re-calibrate their arguments. The next step is for the CCS charging infrastructure to expand both CCS geographic availability and peak amperage to match the capability of GM's gem of an EV.

 

[Qinsp]

I often wondered if ground mounted fans at the DCFC locations would increase the charging rate.

When we do chassis dynamometer testings, we place large fans in front the cars. While they cannot match driving airflow, they assist the puny cooling fans that come on cars. Those on-board fans are only to service idling loads such as low HP engine output, heat from the torque converter fluid, and AC radiators. Once the car is moving, the lion's share of cooling air is coming from outside.

But the bad news is, the aero drag for radiator cooling ducts is high, so you need to minimize that. So it's a balancing act as to how much cooling would be best for the application. Too much? Poor MPG. Too little? Engine output must be capped at peak.

 

[Bluesideup]

Tesla says the Model 3 base version (220 mile range) will charge 130 miles in 30 minutes, which is about 60 kw. The Bolt (238 mile range), at a 55 kW-charge rate for the first 50%, will charge about 110 miles in 30 minutes (as opposed to 90 miles with 45 kW charge rate from 125-amp CCS chargers). Given GM's propensity to error on the side of safety and longevity regarding battery engineering as opposed to Tesla's more aggressive, risk-taking approach, I'll take that slightly slower charge-rate in a heart beat.

Those that slam GM for engineering a "slow-charging" BEV as compared to the prowess of the Tesla Model 3's charging speed need to re-calibrate their arguments. The next step is for the CCS charging infrastructure to expand both CCS geographic availability and peak amperage to match the capability of GM's gem of an EV.

Ya I mean that Tesla only has the most large battery packs out there with the highest charge rates around and even though there are companies that plug into the Tesla superchargers twice a day to fill up and have found that the battery pack degrades about 5 percent in the first 50,000 miles then less than 5 percent in the next 100,000. With hundreds of thousands of other data point out there showing about the same metric whether you supercharge or not. You know pretty standard degradation of the battery over time.

I mean what does Tesla know about keeping large batteries viable during high rates of charge?

 

[Neromanceres]

The MGU (generator/motor) does have enough copper to handle 70kW of monitored charging (regen). The battery is wired to a minimum of 150kW to the MGU motor side.

Unless there is weak link in the actual CCS car-side conductors, it's unlikely to be under 70kW. It is interesting to note the OM says 80kW is required for the quickest charge rate. Assuming they mean At The Wall, the car is probably wired at 70-150kW depending on the circuit.

Was the Norway Test optimum conditions? It appears to still be climbing at 55.5kW which means it's not seeing a ramp rate that would require reduction in load yet. Due to the delay in reported data from sensors, it needs to cut current while it is still ramping up.

From early on, I've been betting it's 60kW or higher due to how low a 1 C charge rate is to a modern battery, and the 70kW regen. But I also said cooling a car that is not moving sucks. There is the problem with charging EVs. No amount of heat exchangers and electric on-board fans are going to match driving at 35 mph.

Keep in mind the OM rating of 80KW was likely based on a charging station with a 500VDC peak charging voltage. Which would indicate a charging current of 160A. Which according to the charging session from Norway looks like the peak charging current for the Bolt EV.

 

[CCIE]

Keep in mind the OM rating of 80KW was likely based on a charging station with a 500VDC peak charging voltage. Which would indicate a charging current of 160A. Which according to the charging session from Norway looks like the peak charging current for the Bolt EV.

The Bolt's battery can't use 500V DCFC, so I'm not sure why they would use that value.

 

[Neromanceres]

The Bolt's battery can't use 500V DCFC, so I'm not sure why they would use that value.

Because 80KW is what would be written on the station for rated capacity.

 

[CCIE]

Because 80KW is what would be written on the station for rated capacity.

I don't understand why they would deliberately put 80KW in the owner's manual unless the car could use it. The rating of the station shouldn't be relevant since the car can negotiate down.

At this point, it seems like the 80KW may have just been a typo.

 

[Ladogaboy]

I'm fairly certain I saw somewhere that the wire size from the Bolt's CCS inlet precluded anything over 60 kw. I'll have to see if I can dig up the reference.

I'm fairly certain that GM used a standard CCS1 plug for the Bolt EV, which I believe is rated for up to 200 A of current. The Bolt EV's charge rate is almost certainly a software restriction. I recall a GM representative stating that the Bolt EV would charge at 50 kW at a minimum, but they still needed to decide how far they were going to push it.

I don't understand why they would deliberately put 80KW in the owner's manual unless the car could use it. The rating of the station shouldn't be relevant since the car can negotiate down.

At this point, it seems like the 80KW may have just been a typo.

There are two plausible theories about what was meant by 80 kW. First, it was referring to a 500 V DCFC at 160 A. This jives with what was tracked at the Vestby. Second, it was 200 A @ 400 V. This seems less likely because most stations won't be set up for 400 V.

Now, depending on how they were tracking this recharge, I see a couple of possibilities. The first is that the charge rate they were tracking was on the tower (total power being delivered by the charger). The Bolt EV's battery is limited to charging at 150 A, and the additional draw was the battery conditioning. This makes sense to me because I've personally tracked the Bolt EV drawing as much as 7 kW in addition to the energy being fed into the battery. The second is that they were tracking it from the Bolt EV's display. In that case, the Bolt EV's max charge current is closer to 160 A, and it will draw even more power on top of that to condition the battery and run climate control. And it will reach a max charge rate of ~60 kW and recharge from <5% to 80% in exactly one hour.

Also, I'm surprised he didn't know that it was going to drop off after ~55% to 100 A. We've at least verified that section of the charge curve.

 

[jsmay311]

I don't understand why they would deliberately put 80KW in the owner's manual unless the car could use it. The rating of the station shouldn't be relevant since the car can negotiate down.

At this point, it seems like the 80KW may have just been a typo.

GM advertised 90 miles in 30 minutes. They didn't advertise 80kW. Rather, "80kW" was mentioned once, buried deep in the owners manual, on page 232 out of 360.

Anyway... simple math works out 90 miles in 30 minutes to almost exactly 50kW (average), which is why I never thought it would be able to do 80kW.

And as for the mention of "80kW" in the manual, as others have pointed out a "50kW" DCFC charger wouldn't actually deliver 50kW to a Bolt due to its <500V battery pack voltage. Instead it would max out at 100A or 125A rating of the chargers and would be less than 50kW. So they put 80kW in the manual because a DCFC with 160A capacity would ensure that the charger would not be the limiting factor in charging a Bolt.

 

[Zoomit]

You might be interested to know that the Opel Ampera-e manual is almost exactly the same as the Bolt EVs; however, they elected to delete that entire paragraph that mentions an 80kW DCFC.

 

[ClarksonCote]

I don't understand why they would deliberately put 80KW in the owner's manual unless the car could use it. The rating of the station shouldn't be relevant since the car can negotiate down.

At this point, it seems like the 80KW may have just been a typo.

Because a DCFC station's kW rating/nameplate is based on 500V and its max current... That's how stations are rated and labeled. So the owner would want to find a station rated at 80kW or higher to obtain the max charging rate in the Bolt given the Bolt's battery voltage. This makes perfect sense to me.

 

[Neromanceres]

I went to the silent cruise event yesterday in Detroit and did manage to speak to some engineers.

They were very hesitant to even talk about peak charging rates. They were strongly emphasising the 90 miles in 30 mins. They mentioned that peak charging rate doesn't have a large influence on the overall charging times and that average distance per time was something they wanted to highlight as that is what most people would relate too.

I brought up the car in Norway on a 200A unit and mentioned that it appeared to be charging in the 150A to 160A area and the representative from GM simply stated "it appears you answered your own question". So I didn't really get any new information.

 

[Zoomit]

Because a DCFC station's kW rating/nameplate is based on 500V and it's max current... That's how stations are rated and labeled. So the owner would want to find a station rated at 80kW or higher to obtain the max charging rate in the Bolt given the Bolt's battery voltage. This makes perfect sense to me.

Not true. The ABB Terra 53 chargers, which are pretty pervasive, are 125A and by your logic would be described as 62.5kW. Yet their handle and data plate clearly shows 50kW.

They were very hesitant to even talk about peak charging rates. They were strongly emphasising the 90 miles in 30 mins. They mentioned that peak charging rate doesn't have a large influence on the overall charging times and that average distance per time was something they wanted to highlight as that is what most people would relate too.

This is true. If every 125A charger magically turned into a 160A charger most uninformed Bolt EV drivers would NOT notice the difference. And if the recharge started above ~30% or so, there would essentially be no difference in how much range the vehicle gained. (Note: typo on bottom axis label, this is over 60min of charging.)