EA DC charge session data points

[fastwheels]

This morning I did a second DC charge at the EA station (8 plugs 350 KWh) in Cadillac MI. I drove 50 miles to get there so the truck was warm. Air temp was 34 degrees. No other vehicles were at the station while I was charging.

Starting SOC: 15% - 44 miles of range predicted in All Purpose mode. Charging set to go to 85%.
Starting charge rate: 133 KW
20% SOC after 7 min, 170 KW rate
30% SOC after 11 min, 171 KW rate
40% SOC after 16 min, 195 KW rate
45% SOC after 18 min, 197 KW rate. <This is the highest rate I observed for the session>
- at 49% charge rate began to drop quickly
50% SOC after 20 min, 164 KW rate. <At this point 103 miles of range had been added>
55% SOC after 22 min, 154 KW rate
60% SOC after 25 min, 143 KW rate
- fast taper point occurred around 62% - rate dropped to 103 KW, then to 57 KW by 63%.
65% SOC after 28 min, 46 KW rate
- at the 30 minute point 146 miles had been added. Charge rate had dramatically decreased. I was hoping for more added miles by the 30 min point.
70% SOC after 39 minutes, 35 KW
75% SOC after 50 min, 35 KW
80% SOC after 62 min, 38 KW
- at 80% SOC, the charge rate began to ramp UP, eventually peaking at 59 KW at 84% SOC
85% SOC after 72 minutes.

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[zefram47]

Boy I hope they're able to do something about that 50-80% part of the curve. An hour to go 15-80% really sucks.

 

[manitou202]

Glad to see 150kW+ for most of the charging between 15%-60%. That seems better than some of the other reports.

Still a problem that it tapers so fast 65%-80%. If this can be improved to around 100kW average for that range it will be much quicker.

62 minutes is too long to go from 15%-80%. Needs to be 45 minutes or less. Ideally less than 30 minutes. That would require an average of 162kW for the entire 15%-80% with no charging loses. So really about 180-190kW average.

A 150kW average with no charging loses would be 32.5 minutes 15%-80% assuming the 125kWh capacity (which was reported by Kyle). This would be acceptable.

 

[fastwheels]

Glad to see 150kW+ for most of the charging between 15%-60%. That seems better than some of the other reports.

Still a problem that it tapers so fast 65%-80%. If this can be improved to around 100kW average for that range it will be much quicker.

62 minutes is too long to go from 15%-80%. Needs to be 45 minutes or less. Ideally less than 30 minutes. That would require an average of 162kW for the entire 15%-80% with no charging loses. So really about 180-190kW average.

yup, my feelings exactly. I would really like to see 10/15% to 75/80% in 30 minutes or less for road trips...

 

[Jarico75]

I wonder if the system interprets 85% as 100% and uses that to do a typical taper when fully charging?

 

[Andystroh]

Anyone smarter than me have thoughts on “I drove 50 miles to get there so the truck was warm. Air temp was 34 degrees”? Is that actually enough to warm the battery?

I don’t know what else goes into it but this winter (albeit in temps colder than 34) I have driven at 80mph in my ID.4 for an hour and still seen severely reduced charging rates (60kW max across several charging sessions over a 1000 mile trip) when I hit a fast charger. Is there a rule of thumb for “warm enough”? Can it only be verified by a battery pack measurement? Should this be enough driving to warm the pack?

 

[skyote]

I wonder if the system interprets 85% as 100% and uses that to do a typical taper when fully charging?

Interesting question. Maybe set the charge level to 100%/Trip to see whether rates improve later in the curve, then just stop the charging "manually".

 

[rraj2k81]

@fastwheels Thanks for the info.
Small correction, the charging rate is KW, the total energy delivered is kWh.

This whole 60% drop-off is really baffling me! 143KW to 43KW is a big drop off !

As @SeaGeo is theorizing looks like someone have fat fingered a configuration in the BMS to cause this.

 

[Trekkie]

Anyone smarter than me have thoughts on “I drove 50 miles to get there so the truck was warm. Air temp was 34 degrees”? Is that actually enough to warm the battery?

I don’t know what else goes into it but this winter (albeit in temps colder than 34) I have driven at 80mph in my ID.4 for an hour and still seen severely reduced charging rates (60kW max across several charging sessions over a 1000 mile trip) when I hit a fast charger. Is there a rule of thumb for “warm enough”? Can it only be verified by a battery pack measurement? Should this be enough driving to warm the pack?

Depends on the design of the battery thermal management system, really.

Tesla Raven model (2019 refresh) has a heater in the pack that if you have fast charging spot in your nav it kicks on and warms the batteries up. The Model 3/Y the thermal is run through the motors cooling system and they use that to heat up the batteries 'some'.

Other cars don't have a thermal heating system at all, so you either need to do 0-60 and brake hard over and over and try and heat things up, or, you get slow charge.

Not completely sure I understand the Rivian system to konw what's going on thermally, but based on those numbers it was 'warmed up' well, the 60% drop off part based on everything I've seen so far is a Rivian thing. So they can 'adjust' it, but yeah those aren't promising right now for long road trips.

I will say that's why I'm looking forward to the OOS review from Kyle & Team, he seems to get all the details of the systems and can explain it a lot better than I just did.

 

[COdogman]

Great info. Thanks @fastwheels

Hopefully they have a solution for this sooner vs later.

 

[SeaGeo]

@OutofSpecKyle another charging section with 195+kw, followed by the really hard taper at 65%.

 

[fastwheels]

Anyone smarter than me have thoughts on “I drove 50 miles to get there so the truck was warm. Air temp was 34 degrees”? Is that actually enough to warm the battery?

I don’t know what else goes into it but this winter (albeit in temps colder than 34) I have driven at 80mph in my ID.4 for an hour and still seen severely reduced charging rates (60kW max across several charging sessions over a 1000 mile trip) when I hit a fast charger. Is there a rule of thumb for “warm enough”? Can it only be verified by a battery pack measurement? Should this be enough driving to warm the pack?

Warm is, I suppose, relative. The battery was certainly warmer than it was when I pulled it out of the garage earlier, and as I plugged in at EA I could hear the Rivian's BMS fans running. How warm it was, who knows?

 

[ADVNOW]

it appears for long travel distance the sweet spot for now is 15% to 65% due to charging time. You'll get to your destination sooner even with more frequent stops.

 

[Scoiatael]

This morning I did a second DC charge at the EA station (8 plugs 350 KWh) in Cadillac MI. I drove 50 miles to get there so the truck was warm. Air temp was 34 degrees. No other vehicles were at the station while I was charging.

Starting SOC: 15% - 44 miles of range predicted in All Purpose mode. Charging set to go to 85%.
Starting charge rate: 133 kWh
20% SOC after 7 min, 170kWh rate
30% SOC after 11 min, 171 kWh rate
40% SOC after 16 min, 195 kWh rate
45% SOC after 18 min, 197 kWh rate. <This is the highest rate I observed for the session>
- at 49% charge rate began to drop quickly
50% SOC after 20 min, 164 kWh rate. <At this point 103 miles of range had been added>
55% SOC after 22 min, 154 kWh rate
60% SOC after 25 min, 143 kWh rate
- fast taper point occurred around 62% - rate dropped to 103 kWh, then to 57 kWh by 63%.
65% SOC after 28 min, 46 kWh rate
- at the 30 minute point 146 miles had been added. Charge rate had dramatically decreased. I was hoping for more added miles by the 30 min point.
70% SOC after 39 minutes, 35 kWh
75% SOC after 50 min, 35 kWh
80% SOC after 62 min, 38 kWh
- at 80% SOC, the charge rate began to ramp UP, eventually peaking at 59 kWh at 84% SOC
85% SOC after 72 minutes.

Thats pretty disappointing. It really shouldn't be falling off the cliff until 80%. At least the first 60% looks good. Hopefully they can improve 65% - 80%.

 

[Aardvark]

Great data. Thank you for posting.
I'm most perplexed by the ramp UP starting at 80%. In 3 EVs that we've owned, and over 200 fast charge sessions, I've never seen a ramp up so late in the charge cycle. There are so many variables, it difficult to speculate a cause.

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