Electric car question.

[just Warren]

Don't know if this has been asked here before and not sure what search terms to use to find out so I'll just go ahead:

Why is there only one charging port on these cars?

Wouldn't it make sense to have multiple ports leading to multiple battery packs and the charging stations multiple cables to service those ports in order to reduce the time needed to charge?

Because isn't part of the time needed to charge a battery pack related to how much capacity you're trying to charge?

So that if you're trying to fill up one big pack doesn't that take you longer than trying to fill up multiple smaller packs?

Would it make the design of the car (or charging station) too complex and therefore too expensive?

Would it be asking too much of consumers to plug in four cables instead of one?

[lee n. field]

Might have to do with power capacity of the charging station.

[dogmush]

Short answer:  It doesn't look like the plug and single on board charger is the limiting factor for charging, so why add more?

Longer answer:
My understanding of current battery chemistry is that the charge controller and power balancing across cells is the most important part of fast charging, battery longevity, and limiting the rapid oxidation of the cells.  That chunk of hardware is pretty expensive and would make duplicating charge ports pretty expensive.  Not to mention the added weight and complexity of the car's system.

From a quick google it looks like in home Tesla chargers are 240V and 80A.  Which probably means they are running on a 100A circuit, which is pretty close to maxxing out most residential power panels.  My panel is 300A total, and that is considered kinda large in my area.

AC Superchargers run at 480V and 300A, and apparently push that through the same single plug and on board controller.  I'm not sure how much more power you want to try and feed an EV, especially in a residential setting.

[Fly320s]

Why is there only one charging port on these cars?

  For the amount of time it takes to charge the car to a sufficient level, one charge port is enough.  Adding a second or third charge port will only slightly reduce the fill-up time.  The cost, complexity, etc. outweigh the small time savings.

Wouldn't it make sense to have multiple ports leading to multiple battery packs and the charging stations multiple cables to service those ports in order to reduce the time needed to charge?

  Why not do the same for ICE cars?  Fill your gas tank in 6 minutes instead of 7.

Because isn't part of the time needed to charge a battery pack related to how much capacity you're trying to charge?

  Yes, but also how well the battery management system can handle the current, the temperature of the batteries, and the ability of the car to regulate that temperature,  and how "full" you want to charge the batteries.  Tesla recommends charging the batteries to 80% capacity for maximum battery life.  I can charge my car from 10% to 80% in about 15 minutes at a supercharger.  And that is plenty for everyday driving.  When using a supercharger, the last 10% takes the longest to complete.

So that if you're trying to fill up one big pack doesn't that take you longer than trying to fill up multiple smaller packs?

  All electric cars use many smaller packs, not one big battery.  Tesla batteries look like AA batteries (18650 cells), but there are thousands of them.  They are all monitored and controlled by the BMS.  If I understand it correctly, not all of the batteries are getting charged each time.  Some get charged more than others, but the 80% capacity is still reached.

Would it make the design of the car (or charging station) too complex and therefore too expensive?

  Yes.

Would it be asking too much of consumers to plug in four cables instead of one?

  Also yes.  I rarely have to charge away from my house.  I've used the supercharger only twice, I think.  Saving 5 minutes of charging time just isn't a factor for me. 

[just Warren]

All right. Thank you.