EV Charger Load Sharing Calculator

How to use this calculator

1. Enter the main fuse / service rating in amps and the supply.
2. Enter the other household load (the rest of the home, in amps) and the number of chargers to share the spare.
3. Click Calculate sharing for the current and power available to charging, and per charger.

How load sharing works

Dynamic load balancing gives EV charging whatever the main supply has spare after the rest of the house, then divides it between the chargers:

An EV charger (EVSE) cannot go below about 6 A per phase — under that, the car will not charge — so spreading too little capacity over too many chargers stops charging altogether.

Spare current to charging power

Load management lets you add a charger without upsizing the service — the charger simply throttles when the house load rises.

Frequently asked questions

How many EV chargers can my supply handle?

Subtract the household load from the main rating to get the spare current, then divide by the chargers. Each charger needs at least about 6 A to charge, so the spare limits how many can run at once.

What is dynamic load balancing?

A system that measures the total load and automatically reduces EV charging when the house draws more, keeping the main fuse from tripping while still charging when capacity is free.

Can I add a charger without upgrading my service?

Often yes, with load management: the charger throttles to use only the spare capacity. Without it, you must size the charger so the total never exceeds the main rating.