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2024 Rivian R1S Dual-Motor — need advice: Fast charging slows down earlier than it used to

JDMHunterCommunity StarterFeb 5, 20262024 Rivian R1S Dual-MotorCentral Florida
On road trips the car used to hold a higher charge rate longer. Now it starts tapering sooner even when the pack is warm. Could this be charger-side variation, battery temperature, software, or an actual battery-health issue? If I fix it I'll come back and update the thread.
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6 replies

TireRider24Community StarterCommunity StarterFeb 5, 2026permalink
Don't clear the alert just to make the screen pretty. Leave the alerts on the 2024 Rivian R1S so service can see what you saw. That's where I'd start. Keep sale price, fees, and rate as three different conversations. Only after sitting overnight so far.
GarageRoadie4Community StarterCommunity StarterFeb 5, 2026permalink
Charge curves lie if you don't match starting SOC and temp. Match starting SOC and battery temp if you're comparing 2024 Rivian R1S charge sessions. I'd do that before spending real money. Stop there until you know. A day of patience here is cheaper than a wrong part. Heat soak after errands is the other window.
SmoothTechCommunity StarterCommunity StarterFeb 5, 2026permalink
I'd treat 12V warnings as a no-ignore. On the 2024 Rivian R1S, I'd get the 12V/DC-DC side checked even if the traction pack looks fine. That's where I'd start. On “motor — need advice: fast charging slows,” that was the fork that mattered for me. Just my two cents from doing this recently. I'm in no rush to be a hero on it.
TireDriverCommunity StarterCommunity StarterFeb 6, 2026permalink
Don't clear the alert just to make the screen pretty. Leave the alerts on the 2024 Rivian R1S so service can see what you saw. Then you'll know the next fork. A shop burned me once by skipping that step. Not trying to scare you — just skip the expensive first guess. Only after sitting overnight so far.
TireDriverCommunity StarterCommunity StarterFeb 6, 2026permalink
That's a good start, but I wouldn't stop there. Try a second charger before blaming the 2024 Rivian R1S — site sharing and pack temp change the curve a lot. Then you'll know the next fork. This is from a 2024 Rivian R1S in Central Florida. A shop burned me once by skipping that step. I keep a notes app thread for this now.
SmoothTechCommunity StarterCommunity StarterFeb 7, 2026permalink
Asking because it changes the advice: Match starting SOC and battery temp if you're comparing 2024 Rivian R1S charge sessions. That's where I'd start. Take it or leave it — that's what I'd do. This is the version I'd tell a friend.
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