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50kwH is a huge charger. You wouldn't need many of such feeds even with hundreds of cars. How long do cars sit in the lot? Do you need to send cars out at 10

by cduzz 3y ago

50kwH is a huge charger. You wouldn't need many of such feeds even with hundreds of cars. How long do cars sit in the lot? Do you need to send cars out at 100% full? Is it good enough to make sure the cars leave the lot with 50-80% full? They're returned, inspected, cleaned, put in the "outgoing" queue. I suspect having DCFC for just the cleaning area and then 16 or 20 or 24a /240v posts for L2 charging the cars as they sit waiting to be rented would more than suffice. Other big issues would be around having to have dedicated parking for EVs and also having charging posts sticking out of the ground all over.

masklinn 3y ago
> 50kwH is a huge charger. 50kWh is not the charger, half the battery capacity for the cars (as decided by GP). And 50kW would not be a huge charger, or even a large one, it's the bottom end of DC charging. > I suspect having DCFC for just the cleaning area and then 16 or 20 or 24a /240v posts for L2 charging the cars as they sit waiting to be rented would more than suffice. Aside from not being very efficient, 24@240 is not really a thing that's used. 32@240 is relatively standard but it's 7.2kW and generally considered a residential AC charger, acceptable when 3-phase is not available (or too expensive). It needs 7 hours to half-charge a 100kWh battery.
- cduzz 3y ago
  I'd suggest that 50kw/h is way too small and way too large. A car rental setup would benefit from having a couple big DCFC setups where cars are inspected / cleaned. EVs charge fast if the battery is empty (and warm) -- so the car comes in, is inspected and cleaned and put on a fast charger, and in 20 minutes will get to ~50% charge (regardless of battery size). As far as "not efficient" or "nobody uses" well, 240 (or 208 if you're in a commercial setup with 2 legs of a 3 phase) is "normal" and a 16a / 20a / 24a AC charger will put reasonable charge on the car while it's just sitting there waiting to be rented again. EV's don't need to be fully charged to be useful so you don't need to put the battery back to 100% before sending it out again. "your car is at 60% charge and has 180 miles of range right now; your car's nav will tell you where to charge if you need more range to get to where you're going. We'll bill for the power if you bring it back to us at less that 60% full. Have a nice day!" I'm not sure what the turnover is for a rental lot -- I suspect "it depends" but I suspect it's not unusual to have cars on the lot for 6-12 hours before they're sent out again. IMO As long as the car has 60% or better charge (or, 150-180 miles of range) it's "good to go". At least for most "airport rental in a major metro area" situation. As far as charging efficiency -- anything charging at 240/208v is "good enough" -- the differences between 16a or 20a or 24a or whatever are minor relative to the bump from 120v to 240v.
deleted 3y ago
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by cduzz 3y ago

masklinn 3y ago

> 50kwH is a huge charger. 50kWh is not the charger, half the battery capacity for the cars (as decided by GP). And 50kW would not be a huge charger, or even a large one, it's the bottom end of DC charging. > I suspect having DCFC for just the cleaning area and then 16 or 20 or 24a /240v posts for L2 charging the cars as they sit waiting to be rented would more than suffice. Aside from not being very efficient, 24@240 is not really a thing that's used. 32@240 is relatively standard but it's 7.2kW and generally considered a residential AC charger, acceptable when 3-phase is not available (or too expensive). It needs 7 hours to half-charge a 100kWh battery.

cduzz 3y ago
I'd suggest that 50kw/h is way too small and way too large. A car rental setup would benefit from having a couple big DCFC setups where cars are inspected / cleaned. EVs charge fast if the battery is empty (and warm) -- so the car comes in, is inspected and cleaned and put on a fast charger, and in 20 minutes will get to ~50% charge (regardless of battery size). As far as "not efficient" or "nobody uses" well, 240 (or 208 if you're in a commercial setup with 2 legs of a 3 phase) is "normal" and a 16a / 20a / 24a AC charger will put reasonable charge on the car while it's just sitting there waiting to be rented again. EV's don't need to be fully charged to be useful so you don't need to put the battery back to 100% before sending it out again. "your car is at 60% charge and has 180 miles of range right now; your car's nav will tell you where to charge if you need more range to get to where you're going. We'll bill for the power if you bring it back to us at less that 60% full. Have a nice day!" I'm not sure what the turnover is for a rental lot -- I suspect "it depends" but I suspect it's not unusual to have cars on the lot for 6-12 hours before they're sent out again. IMO As long as the car has 60% or better charge (or, 150-180 miles of range) it's "good to go". At least for most "airport rental in a major metro area" situation. As far as charging efficiency -- anything charging at 240/208v is "good enough" -- the differences between 16a or 20a or 24a or whatever are minor relative to the bump from 120v to 240v.

deleted 3y ago

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