Electric Car Charging Service size

[augustine23]

Hi All,
I don't have an electric car, but I wanted my garage to be ready for one. If I put in a 240V 60 amp breaker, will I be reasonably future proof? It is an attached garage. I was going to run an 80 amp service to the garage.

 

[kd3pc]

60 amp "should be" fine, unless the manufacturers change between now and then. Each has it's own perspective on how these should be installed, rated and used and what the current requirements are. I would not install until you actually need it. But that is just me. You could contact the maker for the car you might want down the line and install that, knowing you may have to change it later.

 

[augustine23]

I agree, but I wanted the service to the garage to be big enough.

 

[u2slow]

#2 aluminum is a good value ($/amp) and gives you 90A to a sub-panel. That would let you run a charger and have some extra leftover for other tools/equipment/heat.

 

[cybrdyke]

Some of the big luxury EV's can charge at 80A, but the majority of EV's cant (and wont) need anything that high. The bulk of EV's that are out and that will come out in the next few years will charge at 48A, so your 60A circuit will be fine.
Good luck,
CD

 

[acer66]

#2 aluminum is a good value ($/amp) and gives you 90A to a sub-panel. That would let you run a charger and have some extra leftover for other tools/equipment/heat.

That is what I would do too.

 

[Noltz]

I ran 6ga to the garage for 60A service just for the charger. Three other 120v circuits for lighting, tools and small compressor.

Run the 90A service.

 

[justsam]

Early Teslas could charge at 72 Amps using a 90 Amp circuit. It was an option, and few went for it. Today 48 Amp on a 60 Amp circuit seems to be the norm. The NEMA 14/50 seems to be the defacto receptacle, if you are not direct hardwire. If 14/50 is used, breaker at 50 Amps since it is a 50 Amp rated receptacle. In my case I do charge at a 48 Amp max, which requires a 60 Amp circuit. Just to future proof a bit, I used 80 Amp capable wire. Nothing else is on the circuit and no sub panel.

 

[dcg9381]

The "standard" around here is 60A circuit with a continuous 48A charge. As mentioned, some EVs have the ability to charge with more, but 60A will get your EV recharged overnight. I've seen a few Tesla owners install 100A.

I agree with others that the best value is probably 90A in terms of wire, but you're not going to do that with an outlet. It'd have to be directly wired.

 

[mm08822]

The "standard" around here is 60A circuit with a continuous 48A charge. As mentioned, some EVs have the ability to charge with more, but 60A will get your EV recharged overnight. I've seen a few Tesla owners install 100A.

I agree with others that the best value is probably 90A in terms of wire, but you're not going to do that with an outlet. It'd have to be directly wired.

Tesla Gen3 terminals only accept up to #4 Copper conductors.

Installing a subpanel in the garage fed with a 4-wire AL cable would be cheaper than a 2-wire CU feed all the from the main panel. The local Sub-panel provides a great transition option from AL to CU as well. It's also local if a 2nd charger is needed (stagger charger on-times) and can easily add other ckts for garage.

 

[dcg9381]

Tesla Gen3 terminals only accept up to #4 Copper conductors.

thanks for that.

 

[inphx]

...Installing a subpanel in the garage ...

Also if you mcguyver any off grid solar feed with generator relay switch over that panel will afford you a location to splice that in.

 

[wssix99]

If I put in a 240V 60 amp breaker, will I be reasonably future proof?

None of us can tell the future, but 60A will not (as mentioned below) cover the top-of-the-line chargers currently out on the market. Your future self may want a charger with two ports, which would require even more power.

Running large conduit from your panel to your charger location and/or subpanels will give you the most flexibility. You may change chargers and have different needs over time.

My recommendation would be to run the conduit now and leave it empty. When you get the car and the charger, pull the appropriate wire, pop in the correct breaker and go. (Avoid spending money on the big wire today, which may not be exactly what you need in the future.)

 

[wyliesdiesels]

None of us can tell the future, but 60A will not (as mentioned below) cover the top-of-the-line chargers currently out on the market. Your future self may want a charger with two ports, which would require even more power.

Running large conduit from your panel to your charger location and/or subpanels will give you the most flexibility. You may change chargers and have different needs over time.

My recommendation would be to run the conduit now and leave it empty. When you get the car and the charger, pull the appropriate wire, pop in the correct breaker and go. (Avoid spending money on the big wire today, which may not be exactly what you need in the future.)

Bingo

 

[duneslider]

IF electric cars really take off and it becomes the norm to have 1-2 electric cars, solar panels, and back up power since the grid can't handle the load, all you electricians are gonna be very busy. I would venture that a huge percentage of homes in america can't handle 2 60amp chargers. I think most houses in my area only have 100-125amp service, some areas have 200amps.

Either way, the outlook for electricians is looking good.

I am getting ready to put my subpanel in and I am going for the 90amp sub but will keep it in a utility room that touches a garage wall.

 

[Denwood]

The need for 60 amps at the garage really is a factor of your use case for the car. I charge 16 amps@240V and it is more than we need.

You can play around here with charge current/voltage vs range added to various EV cars: https://evcompare.io/charging-calculator/

For example, a Model 3 charging 20 amps @ 240 Volts will gain ~ 19-20 miles of range/hour. Having 50 amps available will likely be just fine for the majority of drivers with 2 EVs. You'll also likely be scheduling charging during off peak times. That model 3 charging at 20 amps@240V would pick up 160 miles of range in 8 hours. Google says the average US commute is 41 miles/day.

 

[jeepxj]

IF electric cars really take off and it becomes the norm to have 1-2 electric cars, solar panels, and back up power since the grid can't handle the load, all you electricians are gonna be very busy. I would venture that a huge percentage of homes in america can't handle 2 60amp chargers. I think most houses in my area only have 100-125amp service, some areas have 200amps.

Either way, the outlook for electricians is looking good.

I am getting ready to put my subpanel in and I am going for the 90amp sub but will keep it in a utility room that touches a garage wall.

these dual port single circuit units are going to become more popular I think.




a 60a, 48a delivered circuit can do 140KWH in half a day roughly to both plugs. that fills up 2 tesla model Ys or mustang machEs, etc from totally empty to 90%.

 

[cybrdyke]

these dual port single circuit units are going to become more popular I think.




a 60a, 48a delivered circuit can do 140KWH in half a day roughly to both plugs. that fills up 2 tesla model Ys or mustang machEs, etc from totally empty to 90%.

Some folks will buy them, but if you're charging two vehicles at the same time, it cuts the power to each car in half, so it takes a really long time for both of them to charge. It probably has an auto feature so that when one car becomes fully charged, it will shift all the power back to the car that needs more charging.
CD

 

[Denwood]

In practice, (if you want the pack to last), pretty much every manufacturer will advise charging to 80% max, unless max range is needed. They also advise fast charging only when needed. I charge based on expected use (using the timer in the car) so that we're generally at 80% when charging stops at 7 am, and no less than 40% in a given day. That's why I mentioned the whole range vs charging thing. Current lithium pack tech dictates that 50% is the "ideal" target to keep a pack at, so you'll likely want to charge appropriately depending on your needs. In other words, you may just keep the car in the 40% to 60% range if that suits your range needs and only do a full charge every now and then to re calibrate the BMS.

If you're planning for EV charging in cold climates (as in -20 C lows), it's important to note that your charging levels will increase by 30-40% in winter vs summer, and you'll want 20-30 amps available per EV for preconditioning if you're heating the car before departure. In summer we charge maybe every 2-3 days (for 4-5 hours), but in winter, it is nightly for 2-3 hours.

We only charge to 100% when heading to camp for the weekend in summer.

All things to consider if you're planning ahead for 2 EVs.

 

[jeepxj]

Some folks will buy them, but if you're charging two vehicles at the same time, it cuts the power to each car in half, so it takes a really long time for both of them to charge. It probably has an auto feature so that when one car becomes fully charged, it will shift all the power back to the car that needs more charging.
CD

yup it does divide. but still able to deliver 2 full car charges in a single 12 hour cycle. when one car drops their power demand down at the end of the cycle they shift back to full power to the remaining vehicle.

140kwh from that unit per 12 hour night. 140kwh in my car would be roughly 375-400 miles of range. so figure that going into 2 cars you're getting 175-200 miles of range per night. assuming a 1.25 hour commute each way of 80 miles. work for 8 hours. still home for 12 hours to charge up again. but that is a hell of a life. the avg us drives 14000 miles a year. or about 40 miles a day. so rough math that duo charger can handle 4x the amount of avg miles driven per day for 2 vehicles. basically covering a huge chunk of the populations needs.

ALL that said I will have a 60a charger per vehicle. going to a 400a service.

 

[Denwood]

Running empty conduit (largest you can accommodate) is one of the best pieces of advice I read here. For my theater project, I wired everything conventionally in the floor joists and walls, but installed empty conduit going from my equipment rack to both ends of the theater. Needless to say, even a year later I was using the empty conduit!