How fast can an R1T charge?

[SeaGeo]

Folks put way too much emphasis on the peak of the charging curve and on the curve itself. What matters is the average C rate for it is that which determines how long it takes to charge.

I'm specifically saying to increase the average below 50% by maintaining near 500A longer.

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[bhopkins]

Folks put way too much emphasis on the peak of the charging curve and on the curve itself. What matters is the average C rate for it is that which determines how long it takes to charge.

Ok, for us non-electricAl engineers, what is the “C rate”?

 

[mindstormsguy]

Ok, for us non-electricAl engineers, what is the “C rate”?

1 C is the power equal to the capacity of a battery (divided by 1 hour).

1C has been the most common “full speed charging rate” for batteries for a long time. Though now many batteries can be charged faster than that.

For example. Charging a 135kWh battery at 135kW is charging at 1C. Charging the same battery at 2C would mean charging at 270kW, and would charge twice as fast.

There’s more to charging than just that, but that’s what “C” is.

 

[bhopkins]

1 C is the power equal to the capacity of a battery (divided by 1 hour).

1C has been the most common “full speed charging rate” for batteries for a long time. Though now many batteries can be charged faster than that.

For example. Charging a 135kWh battery at 135kW is charging at 1C. Charging the same battery at 2C would mean charging at 270kW, and would charge twice as fast.

There’s more to charging than just that, but that’s what “C” is.

Thank you for the explanation!

 

[ajdelange]

C rate is the rate at which the battery is being charged or discharged relative to its capacity. Thus if a battery is rated 100 ampere hours and is being charged at ,8C that means it is being charged at 80 Amperes. A 200 Ah hour battery charging at 0.8C would be taking 160A.

As the voltages of these (Li ion) batteries don't change that much over the discharge cycle we can be (and most frequently are) a little sloppy and normalize by the the capacity expressed in terms of energy. Then we would say a 100 kWh battery being charged at 0.8C is being charged at 80 kW.

It is sometimes more convenient to represent 0.8C as C/1.25 because in that form the denominator is the number of hours it would take to charge it from empty to full if the rate is held constant. Thus a battery charged at 0.8C will charge fully in an hour and a quarter (if the rate were maintained throughout the charge).

As many BEV charge at about 1C (C/1) it would take an hour to fully charge one of them WERE THE RATE HELD CONSTANT OVER THE WHOLE CHARGE. But we know it isn't. It's tapered as the SoC increases. Thus we note that the charge rate for the R1T appears to be right around 1C below 70% SoC and can figure that to take on a 50% charge increment below 70% ought to require about half an hour.

 

[zefram47]

New article on InsideEVs from State of Charge. Tom does a good job of testing the latest on a 350kw charger. Headline data: it takes 42 minutes to get a 10%-80% (~220 EPA miles) charge. Not great.

https://insideevs.com/news/586886/how-long-to-charge-rivian-r1t/

It's important to recognize the difference between what Tom did in this video and the way Kyle at Out of Spec tests. Tom shows a single charging session from 0-100% completion, meaning he shows one of an infinite number of potential charging curves that depend on a ton of factors to include battery and atmospheric temperature as well as initial SoC, etc. Kyle attempted to show the best theoretical charging performance by unplugging when it appeared to be thermal limiting, cool/warm the system, and then plug back in repeatedly to get the maximum charge rate at every SoC level. Kyle's curve is purely theoretical and will basically never be possible in reality, but it gives a good idea of what the truck *could* be capable of with better thermal management of the charging session.

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