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DCFC and battery temps + deeply mediocre efficiency - Gen2

mikehmb

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My name is Mike, and I have a (car) problem
Just got back from a road trip from the Bay Area up to Ashland, OR for some mountain biking, which was awesome.

TL;DR - efficiency on the new R1S Gen2 with 22" brights was not great, though I did have a bike rack and 2 MTBs back there. And battery preconditioning doesn't seem to work. Also, the battery seems to have heated to the point of error while on DCFC. If you've had any weirdness with the cooling circuit, preconditioning, or battery temps on a Gen 2, I'd like to hear about it.

Note: vehicle charges fine to 100% on L2. Also, app & truck set to 100% so this problem did not exist between keyboard and chair. And yes, I had to repeat this about 9 times to the Rivian person who took the service ticket.

Ok, not quite sure where to start, so in order of discovered events:

1) Thursday afternoon, at the Shasta RAN, DCFC after 300 miles on the road. Wanted to bring the charge up to 100% (or near it). At around 85%, got "vehicle error, unplug and try again." Charge wasn't needed so I just left. Battery was at 122 degrees F which seemed high.
2) Sunday returning, planned to hit same RAN (the restaurant at the hotel there is actually pretty good for a roadside stop). Got there with around 35%, planned to let it ramp as high as we could get it so we could make it as far as possible home. Truck tripped the same error around 85%.
3) This time, tried again. Took about 2kWh, then stopped. One more time - about 1.5 more kWh. So got up to about 88% before setting off.
4) On the road, the battery was very hot - stayed up around 115 degrees, until it suddenly dropped to 74, then back up to 90, then back to the 70s. So clearly the cooling was working - ish.
5) Now comes the fun. Same speeds as on the way up, no headwinds - 30% lower efficiency, under 2 mi/kWh. Means I'm not getting home without another charge.
6) Throw it again on a DCFC, this time a gen4 Supercharger. Worked fine, and we left with 50% and 110 miles to go - should be plenty ... ha.
7) Battery is again at 124 degrees after DCFC session. This time, it doesn't go down, so I do a manual battery precondition -limited efficacy after 20 miles, decrease of maybe 5 degrees. Turned it off, 20 more miles, 5 more degrees.

Made it home with 6% to spare, which is way closer than I would have expected, especially with the slow speeds in the east bay and over the bridge.

Anyway, I'm a big proponent of "let the truck do its job" but clearly something is borked, and I suspect it's in the cooling circuit, so off it goes in August to the SC to diagnose.
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Riviot

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It's the ghost of your Gen1 clogging the coolant lines, whispering "You shouldn't have left me, Michael... I'll always be with you, Michael..."

Rivian R1T R1S DCFC and battery temps + deeply mediocre efficiency - Gen2 1000004920
 

SeaGeo

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Gen2 owner here, most of that isn't normal.

120+degrees isn't unusual while DCFC, and Rivian seems to let it sit in the 110 to 120F range after fast charging for a while for some reason, but the rest of that does not match my experience. Submit a ticket with the description above as well as the times and dates of what happened.
 

LeeD804

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Feels like a battery fault. I had mine replaced when it stopped being able to charge past 75%. Rivian actually called me to schedule the appointment before I had a chance to call them - remote diagnostics threw a flag.
 
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mikehmb

mikehmb

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My name is Mike, and I have a (car) problem
Minor update - I tried preconditioning last night while the truck was at home, off, and in the garage. Dropped 22 degrees in 10 minutes.

@LeeD804 - interesting you mention that. When I was trying to use the remote app to submit the ticket, it managed to pick up that the truck threw a fault during the Thursday session and asked if this was what I was inquiring about. We'll see ...
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