Tesla’s promises don’t compute with current physics and economics of batteries

Re:Tesla’s promises don’t compute with current physics and e... by kumarvvr on Friday November 24, 2017 @11:32PM (#15774454)

Comparing on a percentage point basis, you have to ensure that the underlying physical system is equivalent, in this case, the capacity of the batteries.

Current superchargers charge at 2% / minute. I am assuming that's the maximum rate of charge, given the current supercharger infrastructure.

Lets assume that 2% / min is, say, at a 100 kW power level.

When charging a truck, assuming the supercharger technology isn't changed, the charging will still be at 100 kW power level.

So if the truck has 10 times the battery capacity, then the equivalent %age rate of charge will be 0.2%, not the same 2% as the capacity of the battery to be charged has changed.

Personally I think Elon is either going to add multiple charging inputs per truck and combine it with a special supercharger, or have some sort of port in the truck to which a special connector is connected to transfer huge amounts of power safely, not unlike a dock at the under side of the truck, or maybe the front.

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Re:Tesla’s promises don’t compute with current physics and e... by chrishacken on Friday November 24, 2017 @11:37PM (#15774465)

I'm no battery expert, but is it possible that they have several battery compartments that can all be charged simultaneously? Thus reducing charge time?

Edit:

Just read the latter part of your post after I wrote this. I think this is the most likely scenario. "Personally I think Elon is either going to add multiple charging inputs per truck and combine it with a special supercharger,"

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Re:Tesla’s promises don’t compute with current physics and e... by wlesieutre on Friday November 24, 2017 @11:43PM (#15774477)

They do call it a "megacharger," and the port appears to have multiple connections

https://www.teslarati.com/tesla-semi-megacharger-charging-po...

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Re:Tesla’s promises don’t compute with current physics and e... by kumarvvr on Friday November 24, 2017 @11:41PM (#15774472)

Yes it's possible. We could have a power port like a VGA cable with say 10 or 20 independent supplies, simultaneously charging the different battery units.

However those connectors will be very bulky and heavy. Maybe Elon is thinking of a mechanized system, say a power robotic arm sort of thing, or maybe tech similar to the instant battery changing station he demoed a few years back.

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