Charging Annoyances - Light Bar and Estimated Charging End Time

[Flyinryan]

A couple Gen 2 questions on charging...
1) has anyone noticed the estimated charging duration on the screen is inaccurate? My actual charging takes way longer than reported.
2) while charging, isn't the light bar supposed to stay on if the car is unlocked? Mine turns off after few minutes.

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[SPITmadFIRE]

My actual charging takes way longer than reported.

I've never once had a charge take the estimated amount of time. It's always more. The estimates don't accurately take the charging curve into account.

 

[NTinkle]

I've never once had a charge take the estimated amount of time. It's always more. The estimates don't accurately take the charging curve into account.

If you're talking DCFC, yes, it's a little off up to about 70%; more off if going higher.

There's not much charging curve on L2, and it's still quite a lot off if you're very low. If you're up around 35-40% or higher, it seems more accurate. I just know that I'll add about 7.5% per hour on 48 amp, and pretty easy to have an estimate based off that.

 

[SPITmadFIRE]

If you're talking DCFC, yes, it's a little off up to about 70%; more off if going higher.

There's not much charging curve on L2, and it's still quite a lot off if you're very low. If you're up around 35-40% or higher, it seems more accurate. I just know that I'll add about 7.5% per hour on 48 amp, and pretty easy to have an estimate based off that.

I'm assuming it's a battery calibration issue if you're noticing your L2 charging times are way off. A calibration discrepancy of +/- 2% could show as a difference of an hour or more of charging, depending on your L2 speed

 

[NTinkle]

I'm assuming it's a battery calibration issue if you're noticing your L2 charging times are way off. A calibration discrepancy of +/- 2% could show as a difference of an hour or more of charging, depending on your L2 speed

It's not. It charges at a hair over 7.5% per hour - about 11 kW. It's consistent. The percentage is correct. But the TIME it says it will take is off by quite a lot, if it's around 5-10% SOC when starting.

 

[SPITmadFIRE]

It's not. It charges at a hair over 7.5% per hour - about 11 kW. It's consistent. The percentage is correct. But the TIME it says it will take is off by quite a lot, if it's around 5-10% SOC when starting.

I'm saying it's possible the percentages you see are not calibrated correctly. Lithium batteries with many cells need to be charged full to balance and calibrate them. If it were always as easy as hours = kWh remaining / kW then you'd always have accurate results. It's also possible the vehicle is adding quite a bit of padding early in the charge to make sure the charge rate holds consistently before giving a more accurate estimate.

 

[Flyinryan]

I'm starting at about 20% SOC. If the charging rate is accurate why can't the estimated time be more accurate? If I do my own calculation based on 11 kW (22 miles/hr in my case), I get a pretty accurate estimate. Just wish the car could do this calculation for me. I'm sure I'll get a better feel for it over time, just trying to learn the nuances of owning an EV.

 

[NTinkle]

I'm saying it's possible the percentages you see are not calibrated correctly. Lithium batteries with many cells need to be charged full to balance and calibrate them. If it were always as easy as hours = kWh remaining / kW then you'd always have accurate results. It's also possible the vehicle is adding quite a bit of padding early in the charge to make sure the charge rate holds consistently before giving a more accurate estimate.

Last try to get across it's not that: The time doesn't move for some time. it's not counting down like it would be if it was a calibration issue. Don't think a calibration issue would be inconsistent in time, anyway. I've driven from 95 to 3%. kWh matched expected. It sits at the same time to completion for some time, until it reaches a point it becomes accurate. I've only had the truck for 5 weeks and 3k miles, so not a lot of experience with this issue, but have driven Teslas about 40k miles a year for some time. Several have mentioned the same issue in other threads with the Rivian.

To be clear, it's showing about 143 kWh (plus a few 1/10's usually) in capacity, and the % is changing with the amount of kWh's going in, minus a small loss - typically 94-95% efficiency.

One of the recent updates said that the update included a fix for this problem. I can't remember if I've been that low since then. I drive over 100 miles per day and could easily try it except... it's in the shop.

 

[Flyinryan]

I'm saying it's possible the percentages you see are not calibrated correctly. Lithium batteries with many cells need to be charged full to balance and calibrate them. If it were always as easy as hours = kWh remaining / kW then you'd always have accurate results. It's also possible the vehicle is adding quite a bit of padding early in the charge to make sure the charge rate holds consistently before giving a more accurate estimate.

My car's estimate are always way faster than actuals. For example, I plugged my car in last night at 5:30pm and my car said it would be done by 10:30 to get to 70%. The actual time was after 12:00.

 

[NTinkle]

I'm starting at about 20% SOC. If the charging rate is accurate why can't the estimated time be more accurate? If I do my own calculation based on 11 kW (22 miles/hr in my case), I get a pretty accurate estimate. Just wish the car could do this calculation for me. I'm sure I'll get a better feel for it over time, just trying to learn the nuances of owning an EV.

Same experience. It's not really a nuance of owning an EV - just the Rivian. For now. They'll get it fixed in an update. Just figure % needed and how much 11 kW per hour get you - about 7.6% per hour, for the Max Pack. Still - you're right - should be simple for the app to get it right.

 

[SPITmadFIRE]

My car's estimate are always way faster than actuals. For example, I plugged my car in last night at 5:30pm and my car said it would be done by 10:30 to get to 70%. The actual time was after 12:00.

This is how my DCFC estimates have always been. I never pay attention to the L2 estimates because I haven't really cared when they finish.

 

[Manalishi]

A couple Gen 2 questions on charging...
1) has anyone noticed the estimated charging duration on the screen is inaccurate? My actual charging takes way longer than reported.
2) while charging, isn't the light bar supposed to stay on if the car is unlocked? Mine turns off after few minutes.

Regarding the light bar charging status... I see the same, it turns off a minute or two after being locked on any of L1, L2 and DCFC. I would at least like to have it stay on for DCFC, so that I and others can see from a distance how soon I might be done.

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