Need help with CarScanner

[Murse-In-Airy]

Hoping some of our more technical friends here can help an only guy out.

What I’m trying to decipher is which CarScanner data points I should be looking at to tell if a DCFC station is slow because of my car, or because of the station.

A few days ago I needed to drive 300 miles in the cold. No big deal. I know where the stations are. But when I got to a station I frequent (EA in Herkimer NY just off I90 at the Denny’s) for Fast Charging, I could only get 30KW speeds. I tried unplugging and replugging. I tried a different charger. When someone else left, after I had watched them get faster speeds, I switched to that charger… still 30KW speed for me. I stayed for 2.5 hours to ensure I could make my destination. During that time I looked at Car Scanner. No error codes related to charging. But there are so many data points related to charging I wasn’t sure if it said my car was only asking for 30KW speeds, or if the charger was throttled at 30KW speed.

Tomorrow I journey back home and will have to fast charge again. I’m going to try a different EA charging station. But hopefully someone smarter than I can point out what to look at for data. If I’m still getting 30KW speeds I want to be able to show the mechanic where the car is limiting itself.

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[Charge_Rob]

That is almost certainly a fault with the charger (and specifically the cable of the charger).

However, you can definitely verify that with CarScanner - you want to monitor the current available from the charger and the current requested by the vehicle. That should be 500A at a 350 kW EA station. If it's a 350kW EA station and the station is not saying it can provide 500A (and you're not sharing with another vehicle on a "balanced" charger, move to another one.

 

[Murse-In-Airy]

That is almost certainly a fault with the charger (and specifically the cable of the charger).

However, you can definitely verify that with CarScanner - you want to monitor the current available from the charger and the current requested by the vehicle. That should be 500A at a 350 kW EA station. If it's a 350kW EA station and the station is not saying it can provide 500A (and you're not sharing with another vehicle on a "balanced" charger, move to another one.

Thanks Rob. I didn't mention, I tried calling EA to reset the charger and they said no because there was no fault showing On their end. My main concern was that I tried 3 chargers with the same result and everyone else that came and went seemed to get higher rates of charge.

if I’m reading this screenshot correctly, the Charger is saying is can do 455V at 90amps for a max raw of 39KW. (top line) and is actually providing 347.17V at 89amps for a rate of 30.9KW (second line). And then the car looks to be requesting 392V at 89.9amps which would only give me 35.2KW but I’m actually getting a rate of 30.67KW (third line).

Can you tell me if I’m reading that correctly?

 

[Billyk24]

Simple question and possible simple answer: What was your battery temperature? If you don't know, start monitoring as it will provide a lot of answers to question such as yours.

 

[Murse-In-Airy]

Simple question and possible simple answer: What was your battery temperature? If you don't know, start monitoring as it will provide a lot of answers to question such as yours.

The battery was cold. But not 30KW cold. This is my 5th winter with the car. It’s been a lot colder. Usually even at -20 I can get 60-70KWH when the SOC is under 10% (as it was) and without preconditioning (which I did this time). Not to mention, the battery would have warmed as it charged so the speed should have gone up if the temp was the limiting factor.
Good thought, but not the root of my problem this weekend.

 

[RickMachE]

I use two fields:

ChgOA and ChgOAR. OA is the offered from the charger, OAR is requested from the car. I have a screen that I made that has the fields I want all together. This is from the Lightning, but they use the same screen.


Heater power Energy in battery

kW the charger is putting out Battery temp

Actual state of charge Displayed state of charge

Charger offering amps Vehicle requested amps

Instant efficiency State of health

 

[Murse-In-Airy]

I use two fields:

ChgOA and ChgOAR. OA is the offered from the charger, OAR is requested from the car. I have a screen that I made that has the fields I want all together. This is from the Lightning, but they use the same screen.


Heater power Energy in battery

kW the charger is putting out Battery temp

Actual state of charge Displayed state of charge

Charger offering amps Vehicle requested amps

Instant efficiency State of health

Thanks Rick. Glad you spoke up to help an OG out here. So I’ll monitor ChgOA and ChgOAR tomorrow. My screenshot from Saturday has ChgOAR but didn’t capture ChgOA. So I guess I don’t have what I need to see if the offered and requested matched For Saturday. I’ll make a screen like yours and see what I can learn.

 

[kodiakng]

if I’m reading this screenshot correctly, the Charger is saying is can do 455V at 90amps for a max raw of 39KW. (top line) and is actually providing 347.17V at 89amps for a rate of 30.9KW (second line). And then the car looks to be requesting 392V at 89.9amps which would only give me 35.2KW but I’m actually getting a rate of 30.67KW (third line).

the top line is what the charger is telling your car it can provide. since it is only offering 90A that is your limit; the volts on offer are plenty for our mach-es.

the 90A limit could be a site limit (would generally be set on all chargers for a site) or cable limited (usually due to cooling system failure).

as you're seeing from that top line you were doomed. since you tried more than one charger with the same results it might have been a site limit.

 

[Murse-In-Airy]

the top line is what the charger is telling your car it can provide. since it is only offering 90A that is your limit; the volts on offer are plenty for our mach-es.

the 90A limit could be a site limit (would generally be set on all chargers for a site) or cable limited (usually due to cooling system failure).

as you're seeing from that top line you were doomed. since you tried more than one charger with the same results it might have been a site limit.

Thanks so much Kodiak. so you’re saying my “DC Charger Max A” is the same as Rick’s ChgOA”.

I’ll be leaving work in the morning at 100% so I’ll be able to bypass this station and try one closer to home tomorrow. Fingers crossed I don’t see the same limit.

 

[RickMachE]

Thanks Rick. Glad you spoke up to help an OG out here. So I’ll monitor ChgOA and ChgOAR tomorrow. My screenshot from Saturday has ChgOAR but didn’t capture ChgOA. So I guess I don’t have what I need to see if the offered and requested matched For Saturday. I’ll make a screen like yours and see what I can learn.

If you're using the Mach-E profile, and your sessions are saved, you can pull it up and page through the screens until you see it. HV Charger Current Requested and HV Charger Output Current Measured. I just did for a session last February.

 

[kodiakng]

Thanks so much Kodiak. so you’re saying my “DC Charger Max A” is the same as Rick’s ChgOA”.

rick's ChgOA is the same as your "Charger Output Current" - that's the amount of current that is flowing from the charger at that time. you'll need to look at “DC Charger Max A” to know what it is telling your car is the max it can provide.

 

[Murse-In-Airy]

If you're using the Mach-E profile, and your sessions are saved, you can pull it up and page through the screens until you see it. HV Charger Current Requested and HV Charger Output Current Measured. I just did for a session last February.

so this is what was recorded on Saturday. I guess my main question is, is the charger only offering what is requested? Or is the car only requesting what the charger is offering?

 

[Murse-In-Airy]

rick's ChgOA is the same as your "Charger Output Current" - that's the amount of current that is flowing from the charger at that time. you'll need to look at “DC Charger Max A” to know what it is telling your car is the max it can provide.

Alright. Looking back “DC CHG MAX A” is also 90. So that would mean the charger said “thats it for you.” For some reason. That gives me more hope that I won’t be someplace for 2+ hours charging at 30KW tomorrow. Thank You.

 

[RickMachE]

so this is what was recorded on Saturday. I guess my main question is, is the charger only offering what is requested? Or is the car only requesting what the charger is offering?

I am not an engineer, didn't stay in a Holiday Inn Express last night...

Requested is what the vehicle wants. I am looking through my screenshots, hold on. 396 requested, 353 offered.

.

 

[kodiakng]

Alright. Looking back “DC CHG MAX A” is also 90. So that would mean the charger said “thats it for you.” For some reason. That gives me more hope that I won’t be someplace for 2+ hours charging at 30KW tomorrow. Thank You.

so to get back to your main question at the top of the thread: if the “DC CHG MAX A” value (top line in the carscanner dashboard image you posted) isn't in the 400-500A range you won't have a great charging session. if the car is requesting (third line on your dashboard) significantly less current than the top line, the car will be the limiting factor.

our cars have a 400V class battery - they range from ~321V near zero % capacity to ~388V at 100%.

so, when you are in the bottom of the battery, say 5% at 323.5V and charging at 400A you'd get 129.4kW. if you were limited to 90A you'd only get ~29.1kW. as your battery fills the voltage will rise so the it takes less current. unfortunately, our cars derate the current below 400A pretty quickly due to temperature concerns so we spend a lot of time at ~100kW or less.

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