Charging Question

[TheNickGuy]

We moved into a new house in 2014 and the builder included a 240 volt outlet in the garage for a possible electric car. When I brought home the i3, I ordered in and have been using the TurboCord 240 volt, 16 amp cord.

Approximately how much faster could a wall unit 30 amp option charge my car? My TurboCord actually seems to do pretty well...

Thoughts? Has anyone owned or used both options?

Cheers!
Nick

 

[jadnashuanh]

First, you need to determine what the circuit breaker and wiring is to the current device to determine whether you could use a bigger device without upgrading the supply circuit. But, if you doubled the power available, you'd nearly halve the time it takes to fully charge the car. It isn't totally linear because faster charging creates more heat and it will begin to taper off to a slower rate when it gets near the end to finish topping it off. A smaller EVSE doesn't create as much heat in the vehicle's charging circuits, so might be able to run at full rate longer, but its peak is a function of the amount of amps available. The i3 can use up to about 7400W. Divide that by your supply voltage, and that would indicate the maximum amps it can take. For example, my local acv supply is often about 246vac, so 7400/246=30.08A.

FWIW, to use up to a 32A EVSE, you'd need at least a 40A circuit to account for the US code rule that limits continued use circuits to 80% (rather than the max, in this case 40A). Higher currents could be used when powering something that didn't run as long per the code, but not when using an EVSE.