Comparing SR+ to LR

bwilson4web

bwilson4web

Well-Known Member
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Source:

  • Both charged at the same SOC % rate - good
  • 136 mi in 20 minutes - SR+, mine show 140-150 mi
  • 181 mi in 20 minutes - LR
The difference is I start my time AFTER the car starts charging. Their benchmark includes the ramp-up time, ~2.5 seconds.

Bob Wilson
 
I meant 2.5 minutes, not seconds.

When you first plug-in, the car and SuperCharger negotiate for nearly a minute before charging 'ramps up.' I suspect both are checking temperatures and other metrics. A slow ramp-up allows careful monitoring the modules to make sure there won't be an overcharge risk to one of the modules.

My interest is in the full-speed charge and eventual ramp-down. Yes, there is an initial negotiation and ramp-up but very little charge goes into the car.

Bob Wilson
 
bwilson4web said:
I meant 2.5 minutes, not seconds.
Click to expand...

Oh, so I did not see what you did there. ;) I thought you were making a joking analogy with the controversy over using a 1-foot "rollout", or not, when testing 0-60 MPH times.

I wouldn't think that any "negotiation" between the Supercharger and the battery pack's BMS would take that long, since it's happening at electronic speed. A data "handshake" shouldn't take more than a very few seconds. I suspect a two-minute-plus delay would have more to do with the car reconfiguring how the heat exchangers are routing the coolant fluids. In other words, a mechanical change rather than an electronic change.
 
I used the 'time-lapse' option on an iPhone to make a video recording. It include the HH:MM clock from the car which is what I use for my time base. But between the 'time-lapse' recording and coarse clock, errors can be made.

A better approach is an independent clock with HH:MM:SS which I get with my dash cam video. Although the 24 frames/min works, it is broken up into ~3 min, large files that I have to video process. This part takes time and each file is processed individually:
  1. Load each, ~900 MB file and crop and sub-sample 24-to-1. My software requires three passes:
  • 6-to-1
  • crop to screen size (sometimes requires two passes)
  • 4-to-1
With the recent MacOS and video application updates, I may be able to combine these steps and improve processing speed.

SUCESS:

I was able to reduce a ~900 MB file to ~10 MB (~2 orders of magnitude) in one pass by combining both crop and a 12-to-1 frame reduction (Nyquist limit for 1 second resolution.) Combined with a well placed dash cam, we should get more space reduction with 1 second resolution.

I have the most recent firmware update from Sunday afternoon, 2019-32-11, and have plans to take the 1000 km challenge. I'll end it with a full, SuperCharge, session to refine my charging curve. I'm not expecting a great change as much as more precision.

Bob Wilson
 
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