The charger is rarely the expensive part of an EV install. The circuit is. Understanding what drives the price makes it much easier to compare quotes honestly.
The three things that set the price
First, distance from the panel to where the car parks. Every extra foot is conduit, cable and labour, and long runs need larger conductors to control voltage drop. A charger 15 feet from the panel and one 90 feet away in a detached carport are completely different jobs.
Second, spare capacity in your panel. If there is room and the load calculation supports it, the circuit is straightforward. If there is not, you are looking at a sub panel, a load management device, or a service upgrade.
Third, the route. A clean surface-mounted conduit run along a garage wall is quick. Fishing cable through finished walls, crossing a crawl space, or trenching under a driveway is not.
Hardwired or plug-in
A hardwired charger can be set to higher continuous current and is the better choice outdoors, where a receptacle and plug are just two more things for salt air to attack. A NEMA 14-50 receptacle is more flexible if you rent, if you might move, or if you want to use a portable unit.
For most Hawaii installs where the charger lives outside or in an open carport, hardwired wins on longevity alone.
Sizing the circuit
A continuous load is calculated at 125 percent. A 40 amp charger therefore needs a 50 amp circuit, and a 48 amp charger needs a 60. Cable size follows from that and from the length of the run.
Most households do not need the maximum. Overnight charging at 32 amps adds well over 200 miles for most vehicles, which is more than almost anyone drives in a day on any island. Choosing a realistic current can be the difference between needing a panel upgrade and not.
Weather, salt and mounting
Outdoor units need proper weather-rated enclosures and correctly oriented drip loops, not a cable stapled to a post. Stainless hardware matters within a mile or two of the shore. So does keeping the connector holster out of direct salt spray.
We mount at a height that keeps the cable off the ground, because a charging cable dragged across concrete every night fails at the strain relief long before the electronics do.
Two cars, one panel
You can run two independent circuits if capacity allows, or use load-sharing units that split one circuit between two vehicles. Sharing is slower per car but both are full by morning, and it often removes the need for a service upgrade entirely.