Correcting the record

[bwilson4web]

After benchmarking CHAdeMO charging of my Std. Range Plus Model 3, there was an understandable, flat curve that slightly increase with the state of charge. About two months ago, Audi did an e-tron press day and their charge curve had a flat line similar to the CHAdeMO graph.

Then about 8 months ago, the e-tron press announcement claimed it could handle a 700-800 VDC charge. I wasn't the only one confused by these strange charging graphs especially considering neither the BMW i3 nor the e-tron can plug in the Y-Axis, SuperCharger:
https://cleantechnica.com/2019/05/1...charges-over-2-times-faster-than-audi-e-tron/

Matthew Mostafaei, Audi’s manager for e-tron, presented data taken from Twitter during the New York Auto Show without naming the source. (That’s plagiarism.) The data was misrepresented by plotting it on a different axis. (That’s a falsification.) He then used the data to show the e-tron’s charging superiority over the Model 3, when it actually proves the opposite. (That’s deception.) You may call this good marketing. I call it a brazen lie. At best, it is a highly misleading accident.
. . .​

So this is what the authors used to accurately plot e-tron charging:


Absent a more recent, time lapse, charge session of an e-tron, the only data we have is pretty weak. More importantly, one wonders if there are any USA based, fast DC chargers that have a 700-800 VDC capability: https://electricrevs.com/2018/04/16/porsche-gives-new-details-on-us-charging-network/.

Now if we can just find someone to make a 'time lapse' video of charging an e-tron at one of these 800 VDC, Porsche chargers.

Bob Wilson

 

[bwilson4web]

So I took the Youtube video, entered the data, and plotted the values:

• Current limited - could be charger, likely, but could be the battery management system protecting internal wiring.
• Charger kW - 150 kW when the battery voltage and current matched the charger capacity.
• Battery taper - ordinary current fall-off as the battery approaches peak charge.

There was an earlier Audi release claiming it has an 800 VDC battery. To charge this battery from a lower voltage charger, the car would need a boost DC-to-DC converter to step up the voltage. But these are notorious for being current limited and this could be going on. Regardless, both the charger and e-tron wires are not allowed to overheat and melt which is achieved by limiting the current.

In contrast, this is what my Standard Range Plus Model 3 Tesla does:

It will take a little time but I'll try to combine the time vs battery range curves into one chart:

• Tesla Standard Range Plus Model 3 charging 15-25 minutes - this gives a faster trip time than the e-tron. The Tesla used a 120 kW SuperCharger while the e-tron used a 150 kW charger.

Bob Wilson