No one seems to be installing 16 AMP Charger

A 100 Amp EVSE is overkill for most people. A 40A EVSE charges a Model 3 37 miles per hour and 25 miles per hour for a Model X. Most charging is done overnight so this is sufficient for most people. You probably don't need anything faster than a 40A unless you drive more than 200 miles each and every day.

 

Would definitely agree with that for families with only one plug in. For two I would definitely recommend a 100 amp subpanel.

 

I wasn't talking about the subpanel, I was talking about the EVSE itself.

 

Regardless of your opinion of what we need, a Tesla HPWC specifies a 100A-rated circuit. We were preparing the wiring to support such.

 

Well ya, that should go without saying. No vehicle can take up to 100 amps AC. So...it's overkill for everyone.

 

A few things:

1. Electrical circuits are qualified to run constantly at 80% of rated load. This is the case in the US and Canada(IIRC), and likely much of the rest of the world. That means a 100A curcuit can support a car charger running at 80A.

2. A Tesla with dual chargers can accept power from a Tesla HPWC charger at 80A (remember that 80% number?). This has been the case since at least 2013 when we purchased our car.

 

Yes...I understand that first part....not sure where you are getting your info, but per Tesla's own site the P100D's only have an onboard charger rated for 48 amps.

 

That's why I wrote for "most people". I specifically didn't quote you when I commented because I knew you were an outlier and didn't want you to feel I was directing the comment at you.

Gray has an older Model S which I think came with a 40A onboard charger or pay more for dual 40A chargers. They stopped making that and now only have 48A onboard charger. I saw a post mentioning a 72A charger as well. Based on the info on Tesla's site, the current Tesla's will charge at a max of 48A.

 

Interesting, didn't know that about old Tesla's.

 

The primary reason for large charging current capacities is the speed of charging. If your EVSE can provide 20 amps @ 240 volts, it provides 4.8 kWh in an hour. Increase the current to 100 amps and that same 4.8 kWh can be delivered in only 12 minutes.

However, in addition to needing to have a vehicle with an internal charging circuit designed for that much current, you also need much larger wiring (conductor diameter) both in your walls and in that heavy cable that you plug into your car. And this is even a bigger problem for utility companies because they have to size their equipment to deliver that higher current on demand, even if the customer is only going to be using it for a few minutes.

One alternative strategy being developed by Tesla and others is to place a high-capacity rechargeable battery in your garage to supply your EVSE. The battery charges at a much lower current 24/7 and then delivers that energy quickly to your vehicle. And, this can happen at a higher voltage so that the cable you plug into your vehicle can be physically lighter in weight.

There have been various technical reports looking at this problem of providing sufficient energy for rapid charging, especially at highway charging stations where many vehicles may be charging simultaneously and the capacity of the local electric grid is limited.

Watch this excellent 3-minute video which explains the concept.

You can also read "How Batteries Can Bridge the EV Infrastructure Gap" and McKinsey Consulting's more detailed reports "The Potential Impact of Electric Vehicles on Global Energy Systems" and "How Battery Storage Can Help Charge the Electric Vehicle Market."