Our Splitvolt Portable EV charger with standard NEMA 14-50 plug charges at a rate up to 40Amps, and approximately 37mph. (We we also offer a 24amp charger which charges at 21mph.)
If the car is able to support 40amp charging and has 240v, the time it takes to charge, is the vehicle battery range, divided that by 37mph.
However, if the vehicle itself has a lower maximum charging rate, which is the case of the i3, then our charger will match that automatically.
charging cables with NEMA 14-30 and NEMA 10-30.
According to the Car and Driver website, the 2021 BMW i3 specifications state:
“ Lithium Ion Traction Battery w/7.4 kW Onboard Charger, 7 Hrs Charge Time @ 220/240V...“
So, to estimate your amperage, maximum charging rate in Amps, and charge time, taking 7.4kW divided by 240 volts will give you a fairly accurate estimate of the charging rate…
7400 / 240 = ~ 31 amps or roughly 26 miles per hour charging.
(This should be very close, but your exact rate will depend upon your actual voltage--since there is a standard range commonly from 220-240v.)
So if totally empty battery, the charge time would be the maximum range of your vehicle divided by 26 mph .