Emporia 48A vs Emporia Pro: Is Load Management Worth 150 Dollars?

Through a load calculation performed to the electrical code in force where you live, which an electrician does as part of quoting the job. It accounts for the service size, the existing connected load and the demand factors the code allows. The panel load calculator on this site gives you a rough picture for planning; it is not a substitute for the calculation your electrician and your inspector rely on.

Only when the rest of the house is drawing heavily, and usually at times you are not watching. Most overnight charging happens when household load is at its lowest, so in practice a managed charger delivers full output for most of the session. It is trading a small amount of speed for a very large amount of money not spent on a service upgrade.

In most jurisdictions this is licensed electrician work and it requires a permit and an inspection. It involves a new circuit in your service panel, correct wire sizing, correct breaker selection and code compliant terminations, and getting any of those wrong creates a fire risk in a circuit that runs at full load for hours at a time. Have it installed by a licensed electrician and inspected.

Only if your car can accept it and your panel supports it. Most electric cars sold have an onboard AC charger that tops out at 11.5 kW or below, and many stop at 7.7 kW, in which case a 48 amp unit delivers no more than a 40 amp one. Check your car's onboard charger rating before paying for the extra amperage or the heavier circuit.