How long to charge from 85 to 100% using portable charger?

[Joe schmoe]

Title says it all.

Leaving on a trip about 1 PM
tomorrow, first leg is through a charging desert (258 miles) with a headwind.

I want to leave at 100% around 1 PM, but don't want the pack sitting at the voltage any longer than necessary.

My plan is to charge to 85% tonight, then put the Rivian on the charger in the morning before I go to work for half a day.

How much tapering at high states of charge on the portable EVSE running from a NEMA 14-50?

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[jjswan33]

Assuming 15% of the battery is ~20kWh then you would need ~2.5-3 hours to charge at 7.6kW.

 

[Joe schmoe]

Wow, quick response. Thanks

I know the math, but what I'm wondering is if there is any tapering from the already slowish charge rate. I've never charged the truck this high before, but my Tesla slowed significantly above about 95% the handful of times I charged it that high.

 

[Thedude]

It will charge at full rate until 100%.

 

[jjswan33]

Wow, quick response. Thanks

I know the math, but what I'm wondering is if there is any tapering from the already slowish charge rate. I've never charged the truck this high before, but my Tesla slowed significantly above about 95% the handful of times I charged it that high.

Maybe this will help you. This is an older charging curve but it doesn't drop below 19kW at high SOC according to this. You shouldn't see any throttling on a L2 charger.

https://insideevs.com/news/575986/rivian-r1t-charging-analysis/

 

[Joe schmoe]

Thanks.

 

[Hankenstein]

Wow, quick response. Thanks

I know the math, but what I'm wondering is if there is any tapering from the already slowish charge rate. I've never charged the truck this high before, but my Tesla slowed significantly above about 95% the handful of times I charged it that high.

Yep, what TheDude said. 7.6 kW IS the tapering.

 

[WSea]

Assuming 15% of the battery is ~20kWh then you would need ~2.5-3 hours to charge at 7.6kW.

Or about 15-16 miles/hr

 

[stynes]

Also, I would worry about the impact of repeatedly charging to 100% over an extended period of ime, but not sitting there for a few hours.

 

[Joe schmoe]

Also, I would worry about the impact of repeatedly charging to 100% over an extended period of ime, but not sitting there for a few hours.

yep, thanks for the "heads-up." I self-identify as a nerd, and have been driving a Tesla Model S for 8 years (with only about 5% degradation last time I checked)

Every couple of years I'll run it up to 98% or so and then immediately drive it. I'm told it's good for it to balance the pack and keep the numbers calibrated (also supposed to go deep occasionally for the same reason but not leave it there)

Apart from that I don't think it's been outside of the 25-78% state of charge range. I used 100% for some road trips in the 2015-16 time frame before the superchargers got built out, and ran it down to 6-9% maybe 3-4 times.

With the superchargers now my maximum necessary leg is rarely more than 150 miles or so, usually less so I can skip at least every other one.

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