>20% efficiency loss after fast charging

[boardthatpowder]

Noticed this for the first time today as had the efficiency graph showing…

Was traveling at 80mph in conserve for about 50 miles achieving approx 2.2kwh. Had map set to stop at an Electrify America charger just off the highway so battery was preconditioned. Charged from 15 SoC to 50 then continued on with the journey which was another long stretch of road at 80mph in conserve with no change in terrain, weather, or any other conditions. Truck was achieving <1.8kwh. Took about 30mins of 80mph in conserve before it hit the green again.

Anyone else experienced this?

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[crashmtb]

How hot is it outside?

couldbeee cooling the battery after charging

 

[Revelation]

Could be a couple of things:

1.) BMS is still using energy to manage battery temp post-dcfc charging, thus using more energy.

2.) There was more of an elevation change than you are aware of.

3.) You were using more energy to control temperatures for the passenger cabin.

 

[boardthatpowder]

Was 90 degrees outside. Had the air con set to 71 both before, during, and after charging. No significant change in elevation.

I guess this is down to post charging battery management. That’s a significant hit if that’s the case.

 

[SANZC02]

Was 90 degrees outside. Had the air con set to 71 both before, during, and after charging. No significant change in elevation.

I guess this is down to post charging battery management. That’s a significant hit if that’s the case.

Could be BMS but at 80 mph it does not take much of a change in headwind to drop efficiency. My money would be a combo of battery cooling and an increase in headwind.

When I travel, I usually keep an eye on efficiency numbers and if bad drop speed 5 mph at a time to get it higher.

 

[zymolysis]

Was 90 degrees outside. Had the air con set to 71 both before, during, and after charging. No significant change in elevation.

I guess this is down to post charging battery management. That’s a significant hit if that’s the case.

Maybe it is factoring in the energy used to condition the cabin and the battery while you were stopped (getting zero miles per kWh), thereby reducing the 15 minute average when you started traveling again.

 

[boardthatpowder]

Could be BMS but at 80 mph it does not take much of a change in headwind to drop efficiency. My money would be a combo of battery cooling and an increase in headwind.

I hear what you're saying about the headwind, but looking at the weather forecast for that day it was a steady 5mph N / NE wind with 12mph gusts for the entirety of that journey, and I was traveling SW.

Maybe it is factoring in the energy used to condition the cabin and the battery while you were stopped (getting zero miles per kWh), thereby reducing the 15 minute average when you started traveling again.

Yep that makes sense in driving the 15 min average down, but the realtime values were also down compared to prior stopping to charge until about 30mins later they started to recover.

This one's a mystery. I hardly ever charge at public chargers, but out of curiosity I'm going to start checking the efficiency graph before/after charging at them in the future.

 

[zymolysis]

I hear what you're saying about the headwind, but looking at the weather forecast for that day it was a steady 5mph N / NE wind with 12mph gusts for the entirety of that journey, and I was traveling SW.



Yep that makes sense in driving the 15 min average down, but the realtime values were also down compared to prior stopping to charge until about 30mins later they started to recover.

This one's a mystery. I hardly ever charge at public chargers, but out of curiosity I'm going to start checking the efficiency graph before/after charging at them in the future.

By "the realtime values" do you mean the graph? If so, I really don't have any idea what formula Rivian uses to create that graph, but I think that it must involve a lot of averaging, too.

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