Lowering charge amps for Supercharging

[tga]

If the other car is low in the taper (ie, low SOC/high charge rate), you will steal power from the other car doing that.

Not sure why that warrants a disagree. When you plug in, you're guaranteed at least 30kW. If the car in 1A is pulling 120kW, the SC doesn't have 30kW in reserve to give to a new arrival at 1B without stealing some from 1A. Yes, it's an edge case, but not impossible.

 

[TexasEV]

Not sure why that warrants a disagree. When you plug in, you're guaranteed at least 30kW. If the car in 1A is pulling 120kW, the SC doesn't have 30kW in reserve to give to a new arrival at 1B without stealing some from 1A. Yes, it's an edge case, but not impossible.

One, it’s not “stealing”. Two, the effect is so small as to not be noticeable. The superchargers are 135kw, so with minimum 30 kW to the second car, the first gets 105 kW. I’ve never drawn more than 117 kW at a low SOC, and the difference between that and 105 kW for a few minutes is so small it’s not meaningful.

 

[Rocky_H]

The superchargers are 135kw, so with minimum 30 kW to the second car, the first gets 105 kW

Some of them are 135kW. There are still very many that are 120kW. Yes, the effect is relatively small, but it still could be intentionally taking power away from the primary car.

 

[MaryAnning3]

Thanks.

 

[tga]

One, it’s not “stealing”.

OK, "misappropriation"? "illicit borrowing"? Whatever you want to call it, it's a jerk maneuver. Just say no.

Two, the effect is so small as to not be noticeable. The superchargers are 135kw, so with minimum 30 kW to the second car, the first gets 105 kW. I’ve never drawn more than 117 kW at a low SOC, and the difference between that and 105 kW for a few minutes is so small it’s not meaningful.

It's been documented somewhere on TMC that the SC's are built with 12 original 40A chargers. 3 are wired to each phase (277V line-to-neutral), giving 4 groups of 3. The chargers are switched 3 at a time between A and B (again, documented here somewhere) - that makes sense, since (a) you want each group of 3 driving the same output to keep the phases balanced, and (b) you couldn't feed two cars from one set unless both cars were at the same SOC, had identical batteries with identical degradation, etc, or they'd diverge in the CC/CV charge curve.

So a new car shows up and plugs in at your pair. They get (at least) one bank of 3 chargers, you get (at most) the other 9. They get (at least) 3 * 40A * 277V = 33.2kW, you get (at most) 99.7kW. My 85 with 67k miles can hold 99kW or better to at least 33% SOC. The net difference in charge time is probably minimal, but if you're sitting in the car waiting to charge, it's annoying and obnoxious. And, as I said, you're not saving your battery by doing it to artificially lower the SC rate.