Rapidgate Firsthand last Weekend

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martyscholes

Well-known member
Joined
Dec 12, 2018
Messages
52
Location
Colorado Springs
I had read quite a bit about the back-to-back DC fast-charging problems, but did not experience it until yesterday. I intentionally took a 400-mile road trip from Colorado Springs to Flagler CO, to Colby KS, then back. The first charge in Flagler started at 43 kW, taking about an hour to get to 94%. In Colby, the charge started at 24 kW (roughly half) and took about two hours to get to 94%. Back in Flagler, the third charge started at 16 kW, taking about three hours to get to 94%. I noticed that the battery after the first charge was quite hot with the gauge showing the temperature right up to the red line, but showing no red. Ambient temperature was about 35 degrees F.

Since I had plenty of time during the third charge, I did a little bit of reading. It seems that Nissan engineered enough cooling to remove the thermal energy generated during driving. Even though driving consumed about 25 kW on the open road, the air flow underneath the car was enough to remove the heat. Nissan also engineered enough cooling for 6.6 kW overnight charging even in still air. Nissan even engineered enough heat capacity to absorb the thermal energy generated in a single rapid charge while the car is sitting still (no airflow). It seems that Nissan did not engineer for still air while rapid charging a hot battery, made hot by the previous charge. Rapidgate is still a thing, at least in my 2019 SL 40 kWh.

A part of me understands why Nissan did this. The cost and complexity of active thermal management would be a benefit only in multiple rapid charging trips. Honestly, those types of trips are relatively rare. Even so, this is not a car for road trips.
 
His post says "2019 SL 40 kWh" so that's not a Plus.

Was there a reason to go all the way to 94%? Isn't charging quite slow well before that point?

Bolts will do repeated charges at up to 55 kW (w/a sufficiently powerful DC FC) over and over until you hit ~50 to 55% SoC or so and then will start ramping down (to ~37 kW for the first drop). And, it might start out slow if the battery's too cold.
 
cwerdna said:
His post says "2019 SL 40 kWh" so that's not a Plus.

Was there a reason to go all the way to 94%? Isn't charging quite slow well before that point?

It is a regular SL. I was getting nervous about having enough charge to make it to the next Electrify America charger. Out of caution, I charged to 94% at each stop. The whole point of this trip was to see what would happen on a longer road trip. Charging a little too long was a price I was willing to pay to give myself more confidence in the next leg of the journey.
 
martyscholes said:
I had read quite a bit about the back-to-back DC fast-charging problems, but did not experience it until yesterday. I intentionally took a 400-mile road trip from Colorado Springs to Flagler CO, to Colby KS, then back. The first charge in Flagler started at 43 kW, taking about an hour to get to 94%. In Colby, the charge started at 24 kW (roughly half) and took about two hours to get to 94%. Back in Flagler, the third charge started at 16 kW, taking about three hours to get to 94%. I noticed that the battery after the first charge was quite hot with the gauge showing the temperature right up to the red line, but showing no red. Ambient temperature was about 35 degrees F.

Since I had plenty of time during the third charge, I did a little bit of reading. It seems that Nissan engineered enough cooling to remove the thermal energy generated during driving. Even though driving consumed about 25 kW on the open road, the air flow underneath the car was enough to remove the heat. Nissan also engineered enough cooling for 6.6 kW overnight charging even in still air. Nissan even engineered enough heat capacity to absorb the thermal energy generated in a single rapid charge while the car is sitting still (no airflow). It seems that Nissan did not engineer for still air while rapid charging a hot battery, made hot by the previous charge. Rapidgate is still a thing, at least in my 2019 SL 40 kWh.

A part of me understands why Nissan did this. The cost and complexity of active thermal management would be a benefit only in multiple rapid charging trips. Honestly, those types of trips are relatively rare. Even so, this is not a car for road trips.

Did you have the service bulletin completed that is supposed to address this issue? You have to request the service bulletin when you take your car in for service, otherwise they will not complete it.
 
16 kWh charge rate is a pain. The lowest I had heard before (where not station limited) was 20. Even at 10 and 11 bars on my Plus I could get 50 kWh. (I haven’t seen 12 bars)
 
DougWantsALeaf said:
16 kWh charge rate is a pain. The lowest I had heard before (where not station limited) was 20. Even at 10 and 11 bars on my Plus I could get 50 kWh. (I haven’t seen 12 bars)

With my former 40kWh Leaf I would routinely see 16-18kW charging for the third charging stop, but that was before the fix came out.
 
Astros said:
DougWantsALeaf said:
16 kWh charge rate is a pain. The lowest I had heard before (where not station limited) was 20. Even at 10 and 11 bars on my Plus I could get 50 kWh. (I haven’t seen 12 bars)

With my former 40kWh Leaf I would routinely see 16-18kW charging for the third charging stop, but that was before the fix came out.

That's like turbo charged L2 ;)

For anyone that owns a 40 kWh LEAF and has had the rapidgate software fix installed, please share your feedback!
 
alozzy said:
That's like turbo charged L2 ;)

For anyone that owns a 40 kWh LEAF and has had the rapidgate software fix installed, please share your feedback!

@DaveinOlyWA did a good comparison trip last summer, with a write up on his blog: http://daveinolywa.blogspot.com/2019/08/

The key takeaway for me was that a rapidgate charge that used to be only 16kW was 29kW at the same battery temperature after the update had been applied.
 
DougWantsALeaf said:
16 kWh charge rate is a pain. The lowest I had heard before (where not station limited) was 20. Even at 10 and 11 bars on my Plus I could get 50 kWh. (I haven’t seen 12 bars)

Your 62kWh battery is 52% more capacity & therefore heats up quite a bit less than the 40kWh at the same freeway speed because the additional capacity largely through additional cells are discharging at a lower C rate so the heat given off during that discharge process is lower.

And when charging you again have 52% more capacity so your 50KW charge rate is equivalent to a 33KW charge rate in a 40kWh car.
 
I guess some improvement is better than none. In a few years time, if I still can't afford a used Bolt then I would consider a 40 kWh LEAF if the price is right.
 
The road trip experience does have me rethinking my next vehicle when my lease is up next year. Mach-E? I might consider the Ariya if it is a thing and can handle multiple fast charges.
 
I have found that for the 2nd and 3rd charge of the day with a 40kWh car, letting the car sit idle for about 10 minutes makes a real difference in how much power the car will take. Another observation is that slowing down for the last 10-15 miles before a 2nd-3rd quick charge speeds things up too. And lastly keeping the car in the 20-85% range gives the best overall charging speeds.

Running the battery down below 20% and charging above 85% will stretch charging sessions out.
 
I think I understand why charging over 85% would extend the time but why does starting below 20% make a difference? Just curious as I've only needed 1 QC in 3 years of Leaf ownership.
 
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