Charging rates - Why 48A is 2x 30A ?

[Jlindo]

Simple question that I know folks here can answer. On my X 100D, why is charging at a 30A Chargepoint charger adding 16 miles/hour, while charging at my home at 48A is 32 miles/hour.

If I’m not mistaken:

Chargepoint
30A x 240v = 7.2Kw

Home
48A x 240v = 9.6Kw (33% increase)

I'm unclear on why the miles/hour charge rate is 2x?

 

[ilyak]

Most charge point chargers I’ve used delivered 30A@200V, so 6kW. That’s close to half of the 11.5kW charge rate delivered by HPWC running at 48A@240V.

 

[SSedan]

As support to the above statement. I have found ChargePoint to often delivery under 200 volts down to mid 190s on 208 volt feed due to distance from the electrical room.

By contrast my home charger being on a 240volt feed and close to the breaker box can charge at 242volts.
That voltage difference alone accounts for better than 20% difference on the same amperage.

Another angle can be if sitting in the car HVAC uses some power that isn't reaching the pack.

 

[AAARSINIC]

Most commercial areas actually have 200V lines and not 240V. That’s why you see this at a lot of charge point or other charges at store parking lots with lower than expected rates.

 

[Jlindo]

Thanks, I think that answers it.

30A x 200v = 6kw

vs.

48A x 240v = 11.5kw

Accounting for ~2x the charge rate.

Math!

 

[SSedan]

Commercial is usually 208volt but the long run to the parking lot causes voltage to sag below that.