48A vs 40A wall charger in residential home

[jk0291]

I'm talking to my electrician about setting up 48A vs 40A in my home. He's someone I trust to make a fiduciary decision and tells me what I choose won't make any difference in price of set up, but I want to know which is better.
He tells me that the difference in charge rate is 1hr, but 48A is continuous (what does continuous mean? is 40A not continuous?) so if i plan on charging during the day 40A is more desirable. He said I can 'load up my service if I use a lot of power hungry stuff.'

What should I do? I'm completely oblivious to electric jargon, but all I know I love that juicy power so I assumed I was going for 48A, but my electrician got me thinking twice.

Thanks!

 

[WindPower]

You need a 60 amp connection to get 48 amp charging (the 80% rule).
You need a 50 amp connection to get 40 amp charging.
Both are continuous, so you might have misheard your electrician.

Since most homeowners can charge over night and many electrical service providers offer lower rates when charging off peak (I have PSEG which gives a 25% reduction in cost when charging midnight to 6am), it doesn’t matter which you get. Overnight charging will work with either 48 amp or 40 amp rates. If you were charging during the day because you were driving a lot, then of course go with 48 amp charging as long as your current electric service could handle 60amps for dedicated charging.

Personally, I’d advocate for the 60 amp circuit in any case for the future where you might have more than 1 EV. Modern EVSEs can have the charging rate dialed down so even if you had a 60amp circuit, you could charge at 40 amps if your current electrical service doesn’t have enough spare capacity. But if somewhere down the line you upgrade your electrical service, having a 60 amp connection to your EVSE might save you from running new wires to the EVSE.

 

[jcanoe]

When charging at home using Level 2 (240 volts AC) these are the estimated miles that are added to your Tesla Model Y's range, per hour, while charging:

48 amps, up to 42 miles
40 amps, up to 36 miles
32 amps, up to 29 miles
24 amps, up to 21 miles
16 amps, up to 14 miles
12 amps, up to 10 miles

As you can see there is a difference of just 6 miles per hour added when comparing charging at 48 amps and charging at 40 amps. Most people drive an average of 30 miles per day. When you charge at home, overnight, charging at 240V any of these options would be enough to top up the battery pack to 70%/80%/90% (however you have the charging limit set for daily charging.)

If you ever add a second EV then installing the 60 amp circuit (capable of charging at 48 amps) would enable you to add a second charging station to the circuit. Depending on the type of vehicle (Tesla, other) your would be able to use the Tesla Wall Connector's automatic load balancing option when more than one Wall Connector is installed on a circuit.

 

[ATPMSD]

If your panel has the capacity then I suggest you run a 60-amp circuit, upgrading later can be expensive. If you run a 60-amp circuit make sure the wire is rated at 60-amps. A common mistake made is to run #6 romex which is rated at 55-amps, this is not 60-amp wire and cannot be used on a 60-amp circuit.

Also, if you are thinking of adding a 2nd EVSE later then, unless your breaker box is in the garage, you should install a sub-panel and then run the connection from the sub-pannel to the wall connector. Ideally you should run a 100-amp circuit to the sub-panel to suport running two wall connectors at nearly full throttle, which would equal 40-amps each, but a 60-amp circuit is fine and will give you 24-amps each. Doing this now will save you money later.

 

[Art84]

I have set up my equipment to support a maximum of 48A. But I changed the current in the car settings to 24A for overnight charging, because this speed of charging is more than enough for overnight charging. But my equipment has room for faster charging at 48A if/when I need it.

If you do a 48A setup, make sure that you'll use the right wire for the 60A breaker. The #6 ROMEX is not really the right type of wire, as mentioned above, but unfortunately very often used. It would work for 40A setup (50A breaker) but not really for 48A setup (60A breaker)

 

[ATPMSD]

I have set up my equipment to support a maximum of 48A. But I changed the current in the car settings to 24A for overnight charging, because this speed of charging is more than enough for overnight charging. But my equipment has room for faster charging at 48A if/when I need it.

If you do a 48A setup, make sure that you'll use the right wire for the 60A breaker. The #6 ROMEX is not really the right type of wire, as mentioned above, but unfortunately very often used. It would work for 40A setup (50A breaker) but not really for 48A setup (60A breaker)

FYI it is less efficient to change at 24A than at 48A. Not much of a difference, but some.

 

[Art84]

FYI it is less efficient to change at 24A than at 48A. Not much of a difference, but some.

I know, but this "less efficiency" is not a big deal at all...

 

[240vPlug]

Your paying for it and if there is no cost difference then I would surely go with a 60 amp circuit for 48 amp charging. This will future proof your setup. Also may make an even bigger difference if you get a vehicle with a larger battery pack in the future. Your getting a 17% increase in charging rate for no extra cost.