What kind of wiring for an electric car?

Factual Questions
21

Unless you have a car in mind or plan to buy one in the next year or two, I would hold off. It’s a rapidly changing field and you might find that anything you do is a waste of money.
For example, think about all the people that built houses in the 90’s and put one or two ethernet ports in every single room. Sure, it’s still nice to use wired instead of wireless when possible, but back in the 90’s, we had no idea how prevalent laptops would be or that tablets or cell phones (with no ethernet ports) would even exist. Those people that spent an extra few grand wiring up their entire house don’t use 90% of those ports.

So you’re planning to buy an EV in, say, 5 years. You’re not sure what you’re going to do so you just have the service up’d to 100 or 200amps and run what you think you might need over to where you think you’ll need it. Total cost, ~$1000. In 5 years CNG might be the way to go or Hydrogen Cell technology may become the norm.

My suggestion is to leave it alone for the moment. Go ahead a drywall the garage and when you get closer to buying an EV, then you can upgrade and run (and surface mount) the wiring.

22

I wouldn’t up the service until it’s needed, but wire is cheap. Run a couple of 6 gauge wires but don’t bother with outlets yet. Mark the wall to indicate the end of the 6 gauge. If you do end up getting an EV you can easily put an outlet in that matches whatever you need.

23

I agree completely. In the case of electric cars, there’s a similar “wireless” technology that may change things. That’s those inductive charging pads (barely worthy of the term wireless, the 2 sides of the circuit are inches apart). Big advantage of those is you don’t have to plug in. Those will probably only trickle charge, as inductive charging has losses and so many people may still have both kinds of charger. (you’d drive over the induction pad, get out, the car or the wall charger would softly chime to remind you that maybe you should plug in to save power, and you’d ignore it and go inside, knowing your car will be charged enough to use the next morning)

If things go well, apartment complex will have these for residents, and it will be all anyone there ever uses. Hopefully, Federal vouchers or tax credits will exist to encourage widespread installation of these things.

24

So running #10 wire for a charger probably wouldn’t be worthwhile?

Now that I think about it I need two outlets for my lights, and I probably won’t want to unplug any EV charger whenever I want to run the lights. So what I’ll do is just run #14 wire an put in a duplex 6-15, then think about what, if anything, I want to do for a future charger when it’s time to drywall. I have no shortage of breaker spots in the subpanel.

25

Yes, if your concern is planning for the future, pull the wires or whatever else you need to do before finishing the garage, and leave the actual hooking for when needed. If that means running TWO circuits for future charges, then do so.

(Of course, one of the questions to ask in future is what cars or chargers support scheduling - considering it’s likely that peak metering and time-dependent electrical costing will come to your locale if it’s not there already, taking turns charging is a good idea. Plus, you want to plug in when you get home, but don’t want to necessarily start charging until after the supper electrical peak is finished. )

I don’t think most people appreciate just how much power / current is required to charge (and then operate) an electric car. I would be scared of any wireless tech than can generate even a fraction of that. 40A at 240V is 96 100-watt bulbs, or 400 CFC equivalents. This ain’t your cellphone.

26

It’s not really “wireless”. As I said, the pads are very close together, even touching. (motors in the car may have to lower the pad in the car to touch the one on the ground. It would retract when it detects the key fob approaching the car.)

Think of it as 2 sides of a transformer, or 2 halves of an induction motor. That’s all it is. The big advantage is that both halves can be sealed and the pads on the ground can last for decades. There’s no pole or box impeding traffic in a parking lot. You don’t have to move a cable to the car. Just park, get out, and there would have to be some kind of automated payment negotiation where the car agrees to pay for the electricity so long as the rate is reasonable.

We absolutely have to have this on a wide scale, it makes electric cars feasible (that, and cheap long life lithium-iron batteries)

Why? The simple reason is that if widespread induction charging pads are everywhere, with an entire dedicated row of them at most stores, most places of employment, most apartment complexes, and in homeowner’s garages, it does several things.

It removes the problem of damage to the car’s batteries from rapid charging. It lets the car run climate control. It stops range loss in cold climates, because the car can keep the battery pack warm with heaters and charge the pack. It’s more convenient and saves people time, also eliminating reliability issues - most people, if the charge pads function, would never run out of power.

Finally, it works in conjunction with solar. Time of use metering means that mid-day power is probably going to ultimately be the cheapest power available because that’s when all the solar produces maximum power. People with jobs and who can afford electric cars won’t be home then, but they might be out shopping or at work. And it lets all the yuppie apartment and condo residents who don’t own garages also buy electric cars.

A logical thing to do would be to make the tax credit/voucher require the inductive charge pad installations be in the next most favorable spot in a parking lot to the handicapped spots. Parking there if you don’t have an EV would be the same tow away/big fine as taking a handicapped spot.

I don’t have an EV yet myself, but I see the necessity of doing this. They are unlikely to be competitive with gas cars on a dollar for dollar basis for another 10-20 years because the batteries in them are so pricey.

27

I’d mostly agree.

in the likely places where you’d eventually plug in a charger (middle of either side of the garage, and centered in front of each parking space) put a 4-inch square electrical box. Then run a 3/4" or 1" conduit up to the ceiling level, above where your drywall ends.

Then just leave the boxes & conduit empty for now, and install your drywall on the walls.

When the time comes that you need to install wiring for this, technology will have changed (as people have said) – but not the technology of empty, accessible electrical conduit. Those will still be usable, for whatever type of wire or charger that’s needed. And the installer will be quite happy to see these available, and you won’t have to worry about re-doing the walls.

28

Very good point and idea.

29

My point was, just run the wires you need to run. They don’t need to be connected at the electrical panel or in the garage. (as mentioned, just leave them in an electrical box, ready for the appropriate hook-up). That’s even easier than running conduit and pulling wire later.

I assume that, unless you want to get an electric SUV or Hummer, the proper gauge cables for today will be correct for tomorrow. You can’t go wrong with bigger (thicker) than necessary cable.

I also assume charging pads that require you to jackhammer the floor of your garage to install, will have limited acceptance.

30

The ones I’ve seen described install by a few lag bolts around the periphery driven into the floor. Surface mount the wiring in a conduit sized to be drive-overable and you’re done.