(US) Home charging: outside? Multiple? (lemmy.world)

submitted 1 year ago* (last edited 1 year ago) by AA5B@lemmy.world to c/tesla@lemmy.world

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I’m considering installing home charging (ok, I’m considering a Tesla so formulating my requirements for charging) so wanted to ask your experience for things that aren’t clear to me

the idea of multiple chargers appeals to me since there’s usually more than one car in my driveway. I like how the home charger has power sharing and I certainly don’t need concurrent max charging, but ……

— my panel is crowded. It’s unclear whether multiple chargers need to be on separate circuits or can share one? If can share, are there size requirements? One option is to put in a “big enough” circuit as the biggest expense but not worry about a second charger when I need it. But can they share a circuit? How big does it need to be? Or would I need a sub-panel in the garage? I don’t like all the extra connections for such a high draw circuit, but it would add flexibility

— anyone with experience having the charger outside? Would I regret it? I have a one car garage but have realistically never use it for a car. If I install the charger inside the garage, I’d generally snake the cable under the door

— for the universal charger, does it also have along cable or are there any placement limits? My driveway is one car wide by two long. If I park one in front of the other as usual, would I have any problems charging two cars at once? 24’ cable seems like it ought to be enough?

—-

Edit: I ended up installing only the one charger, and it’s outside. I verified I can park my ICE car up by the garage, and the cable is long enough to stretch the length of that to charge the Tesla in front.

Tesla’s list of certified installers was not helpful. Most wouldn’t even call back and the one that did said i was out of his area. However when I called my usual electrician, he was very familiar with installing Tesla chargers.

To move one circuit from my main to a sub panel, string a cable across my open basement ceiling and out a small hole in front of my chimney ended up costing $2,400. However I live in a high cost of living area and a new stove circuit had cost $2,600, so I guess it’s a fair price

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[-] ch00f@lemmy.world 4 points 1 year ago

Tesla’s hpwc communicate wirelessly to share a single breaker. I have three wired to a single 60A breaker in my home.

You just fork the wires using Polaris connectors, and make sure to buy a torque driver to be sure you’re applying the right amount of torque to the screw terminals.

[-] AA5B@lemmy.world 1 points 1 year ago

Great! That seems like the simplest approach, with room for convenience.

Is the power sharing flexible, so it can use any combination between a single charger taking the full load to all sharing equally, to random balances?

[-] ch00f@lemmy.world 2 points 1 year ago

I’m not sure exactly how it decides, but yeah. It’s basically that. I usually see it split 50/50 between two cars, but if one can’t take the full 24A, I’m not sure how it handles the split.

I do know if they lose communication, they each reduce to 1/3, so there’s never a risk of blowing the circuit.

But again, if you plan on doing this yourself, buy a torque driver and pay attention to the specs. I had an install that worked fine for two years before spontaneously exploding. It was all contained inside a flame retardant junction box, but sparks still shot out the drain hole and nearly caught my yard on fire.

The recommended torque is more than anybody can do with a standard screwdriver. Torque drivers come with t-grips.

[-] Steev@lemmy.world 2 points 1 year ago

The only place I could install my wall connector last year was outside. It has been great and I’ve had no issues with weather for it.

[-] blueeggsandyam@lemmy.world 0 points 1 year ago

In theory they could share a breaker circuit. The problem is for them not to constantly trip the breaker you will have to limit the charging by half the total amps. So if you current circuit is 60A you want to keep it around 50A. That would make it 25A per car. This would work but would cut the charging speed of each car in half. How big is dependent on how fast you want to charge each car.

When I got my charger installed, I was limited by my breaker box. The total amps going to the breaker box is limited by the electrical ordinances in your area. The second box and line would have cost me $6000 more so it wasn’t worth it for me.

I don’t have experience with outside chargers but I had seen options for weather proof boxes for them. I stayed at a hotel several weeks ago that had the tesla consumer chargers outside without any additional weatherproof around them. I guess it is technically possible. The main problem is going to be the electrical connection. Outside lines require trenching and often additional permits. It is probably feasible just not cheap.

[-] AA5B@lemmy.world 1 points 1 year ago

if you current circuit is 60A you want to keep it around 50A. That would make it 25A per car

Is it not flexible? If you have one car charging, shouldn’t it take the whole amount? I’m fine with one car charging at max, or two charging overnight

Outside lines require trenching

In this case, it would be attached to the side of my garage either way, so no trenching. If I usually park my car in the driveway, is it more convenient to have the charger attached to the outside of the garage, or safer and more reliable to attach it inside and have to snake the cable under the door to charge?

[-] blueeggsandyam@lemmy.world 1 points 1 year ago

Yes, but it would require changing the limit for the car. There is no way for the cars to know the limit of the circuit. If one cars is pulling 50A and you plug in the second, it will try to pull the max also. That will trip the breaker. Teslas limits can be set in the software and the Tesla charger itself. They can also be set on a schedule.

It should be safe to have it attached to your garage. The new Tesla chargers can also be set to only allow your cars to charge. The garage door may not close with the cable there. Most newer doors have a senor to make sure it doesn’t crush you. Any resistance and the door reverses.