Which Home Charger Should I Buy?

[Jayfaz]

My wife and I are both considering getting Model 3s as our next cars. Is there a home charger that can charge two vehicles at once or do we need to purchase two chargers? What is the amperage requirements of a charger? The house we purchased is pre-wired for 30 amps, but can run more capacity if needed.

 

[Doctor X]

We have two Teslas and only one wall charger. We really only charge each car about once a week, maybe twice a week in the really cold winter months in Canada. So we have found no need for more than the one charger to fill our needs. Good luck with your purchase. We love our cars!

 

[brkaus]

The Tesla wall charger can be set to limit itself to the wiring size you have in place. The portable adaptors limit current use by the plug type. So you can safely use any of the Tesla options with a 30a circuit.

How many miles do you drive per day in each car?

We have a Model S and a Model 3 and share a single Wall Charger on a 50a breaker (40a charging).

I've been considering adding a second wall unit (technically it's called a "connector"). They have a feature that allow up to 4 to be wired together and not exceed a preset limit as a group. It's a pretty nice feature in that price range if you need it. It wouldn't charge two cars any faster, but it would avoid me occasionally having to go out and swap cables on the cars in the night. But, I've only had to do that once or twice so I haven't spent the extra money on it.

I limited myself to 50a due to a utility company plan here in Austin. Plus, most I could get was 60 per my electrician. Large house on 200a panel.

 

[jjrandorin]

My wife and I are both considering getting Model 3s as our next cars. Is there a home charger that can charge two vehicles at once or do we need to purchase two chargers? What is the amperage requirements of a charger? The house we purchased is pre-wired for 30 amps, but can run more capacity if needed.

The easiest way to charge 2 teslas at once (if you want to do have the capability to plug them both in) would be (2) tesla wall connectors ( the charger is actually in the car, its called a wall "connector".. mentioning it so that you dont get "corrected" too many times in a thread like this by others).

As mentioned, the tesla wall connectors can be wired to use one circuit and share the power intelligently between each other. Both cars can charge at the same time and not exceed the circuit charging capability. You might find you dont need to charge both cars at once, depending on your driving schedule... but it would be convenient to just "plug both cars in" and forget it when you get home.

The tesla wall connectors are also the least expensive "really good" charger for tesla's.

 

[srs5694]

There are EVSEs that can handle two cars, but AFAIK they're all very expensive commercial units, not something you'd buy for a home.

As others have said, Tesla's Wall Connector EVSE is capable of talking with others of the same model to share a single circuit, but I don't know much about this feature. Because Teslas use their own type of plug, if you're 100% sure you'll be a two-Tesla household, chances are this is your best bet. If you think there's a significant chance you might want one or both cars to be some other brand of EVSE, though, you might want to look into third-party EVSEs that have J1772 plugs, then use Tesla's J1772 adapter to charge the Tesla. Most EVSEs can't do the type of load sharing that Tesla's can, but IIRC, the eMotorWerks JuiceBox can do this. (Please research this further before buying; I may not be remembering the company correctly.)

One more point: A 30-amp circuit is a little on the weak side for charging a single Tesla, much less two of them. To be sure, it will get the job done in most cases, but if both cars return with low charge one night, it's possible that one or both cars won't be fully charged by the next morning. The Model 3 SR and SR+ can charge at up to 32 amps, which requires a 40a circuit (hence, 80a to charge both cars simultaneously at full speed), and the LR variants can charge at up to 48a, IIRC, which requires a 60a circuit for a single car. A 30a circuit can charge an EV at a maximum of 24a, so that's only half the Model 3 LR's capacity, or 1/4 that if you've got two cars that are charging simultaneously and splitting the current. To be sure, that may be adequate if neither car has been driven more than a few tens of miles and if they're charging overnight; but if they've been driven a collective total of hundreds of miles or if they must be charged more quickly, you may want more capacity. Thus, you may want to ask your electrician what it would cost to upgrade the existing 30a circuit to something bigger. This could get pricey if it entails upgrading your house's supply, though.

 

[ewoodrick]

Semantics.... You don't need chargers, they are built into the car. What you need are the cords and somewhere to plug them into. A cord, the UMC does come with the car.

How much charging you need depends on how much driving you do. My wife charges off of 120V 15A plug and that covers her needs. And she doesn't even plug in every day.
I charge off of a NEMA 14-50 with a UMC that I bought extra, jus to have one at home and in the car, so I don't have to plug and unplug.

The biggest issue with charging two cars is can the cable reach both cars and do you both need to charge each evening. For my wife and I, our charge ports are too far apart. Sure we could switch spots, but that it way too hard.

If you aren't going to buy at the same time, just solve the first problem and then you can have a better feel of just how much charging that you need and what your options are. For us, 2 120V plugs would probably work.

 

[Rocky_H]

A lot of this depends on how much driving you do with each car, which is what @ewoodrick was getting at. We currently have a 50A outlet for our one Tesla and don't have a second electric car yet. But we work at the same place, so we don't have "his car" and "her car". It's more like "primary car" and "secondary car", which only gets used a few times a week. So when we get a second electric car, we probably won't bother putting in a more expensive connector. The secondary car can probably just get by with using the 120V outlet.

The power sharing Tesla wall connectors would still be a pretty good solution to take advantage of that 30A circuit you have, though, because it can automatically shift amps to the other car when one finishes.

 

[davewill]

My wife and I are both considering getting Model 3s as our next cars. Is there a home charger that can charge two vehicles at once or do we need to purchase two chargers? What is the amperage requirements of a charger? The house we purchased is pre-wired for 30 amps, but can run more capacity if needed.

The Tesla wall connector can be set for different amperages with a switch internally. The mobile connector can be used at different amperages by buying the right adapter.
I'm going to give you low, middle, and high cost approaches.

Low: Put a 14-30 receptacle on the existing 30a circuit, and add a 14-50 receptacle on a new 50a circuit. Use the mobile connectors that come with the car with a 14-30 and 14-50 adapter respectively. That will let you freely charge both cars every night. A M3 SR+ will be able to charge at full speed on the 14-50.

Middle: Put a new wall connector on the existing 30a circuit, and add a second wall connector on a new 60a circuit. That will allow you to plug both cars in every night and wake up to full batteries. The 60a circuit is enough that an M3 LR could charge at full speed.

High: Ignore the existing 30a circuit, and put in a new 80-100a circuit. Connect two wall connectors to that circuit, connect a data cable between them, and set them to share the one big circuit. Any kind of M3 will be able to charge at full speed on either plug, but if both cars are charging at the same time, they will be limited to half of the size of the circuit you install.

You can also combine low and middle by using a mobile connector on the 30a circuit and a wall connector on a new 50a or 60a circuit.

 

[davewill]

...
The power sharing Tesla wall connectors would still be a pretty good solution to take advantage of that 30A circuit you have, though, because it can automatically shift amps to the other car when one finishes.

I have to disagree with this a bit. Unfortunately, in the sharing scenario, when one car finishes, but is still plugged in, it keeps 6a of the shared circuit in reserve. That means the other car would only charge at 18a. Yes it works, but not all that well.

 

[Rocky_H]

I have to disagree with this a bit. Unfortunately, in the sharing scenario, when one car finishes, but is still plugged in, it keeps 6a of the shared circuit in reserve. That means the other car would only charge at 18a. Yes it works, but not all that well.

Yes, I'm well aware of the 6A holding. I did overlook that he mentioned that more capacity with an extra run could be done apparently easily. I was thinking of making decent use of that 30A circuit that is already installed and not having to add another wire run.

Also, I guess my paradigm seems to be less miles than some of you seem to drive. Your description of "not all that well" seems pretty OK to me. For example:
Let's say it does get to run for 10 hours overnight as the lesser, or secondary charging car. Even if it's only running at 6A for the first 6 hours before it gets to ramp up to 18A for the last 4 hours, that is still about 25 kWh delivered. Model 3 getting about 4 rated miles per kWh, that's about 100 rated miles refilled every night, even in a slightly bad scenario while the primary car is getting even more than that. And if there's a day that one of the cars really does need to catch up a bit more, you could let that one take the whole 24A while the other car uses a normal wall outlet for that night. That seems pretty decent to me with the existing wire run, but if people drive a lot of miles with both cars, then that could be a struggle.

 

[eprosenx]

My wife and I are both considering getting Model 3s as our next cars. Is there a home charger that can charge two vehicles at once or do we need to purchase two chargers? What is the amperage requirements of a charger? The house we purchased is pre-wired for 30 amps, but can run more capacity if needed.

There has already been a lot of great information shared in this thread specific to your situation. Here is some background info that might also be a good read for you (I wrote these up after answering a lot of the same questions over and over again):

How Should I Charge My Tesla? – Article625.com
Tesla Mobile Connector Gen 2 vs Wall Connector – Article625.com

But your situation of two Teslas and an existing circuit is unique, so not meaning to kill the conversation!

I would add:

Can you post pictures of you main electrical panel, meter, etc...

I have not seen much discussion yet in my skim of this thread whether you have a lot of remaining "load capacity" of your main electrical service. That may greatly impact your installation choices. If you have lots of available capacity and moderate charging needs, just adding a second NEMA plug may be the way to go. If you are tighter on service capacity, the dual Wall Connector strategy (sharing a single circuit) may be advantageous as it can make the most effective use of whatever capacity you may have remaining.

 

[OCR1]

We have two model 3’s sharing a single wall connector with the 24’ cable. Since we both have LR RWD models and rarely drive more than 50 miles per day we never really need to charge both cars at once. But on occasion when we do, I plug one in at night before we go to sleep, and then I plug the second one in around 6am when we wake up. We have cheap electricity until 8am.

With a wall connector and the LR models you can charge at 44 miles/hr so even a two hour charge adds 88 miles to the car. I can’t imagine how many miles you would both need to drive to really need to separate chargers.

 

[RFernatt]

I share a JuiceBox Pro 40 between a Tesla and a Leaf and that works fine, but it's rare that they both need charged at the same time. Depends on your driving needs as to whether you really need two EVSEs or it's just a nice to have. You could use one and then pull the UMC out of the car if you need to charge both. Having another 240 outlet would be nice, but 120 might cut it in the occasional pinch, again depending on driving needs.

 

[Leafdriver333]

Tesla comes with plug in cable.
No purchase necessary.
You just need two 240v 50a outlets.
If you share one outlet you could protect the cable with something like this I bought from Amazon.

 

[F14Scott]

Yes, I'm well aware of the 6A holding. I did overlook that he mentioned that more capacity with an extra run could be done apparently easily. I was thinking of making decent use of that 30A circuit that is already installed and not having to add another wire run.

Also, I guess my paradigm seems to be less miles than some of you seem to drive. Your description of "not all that well" seems pretty OK to me. For example:
Let's say it does get to run for 10 hours overnight as the lesser, or secondary charging car. Even if it's only running at 6A for the first 6 hours before it gets to ramp up to 18A for the last 4 hours, that is still about 25 kWh delivered. Model 3 getting about 4 rated miles per kWh, that's about 100 rated miles refilled every night, even in a slightly bad scenario while the primary car is getting even more than that. And if there's a day that one of the cars really does need to catch up a bit more, you could let that one take the whole 24A while the other car uses a normal wall outlet for that night. That seems pretty decent to me with the existing wire run, but if people drive a lot of miles with both cars, then that could be a struggle.

I agree with this, and think two linked wall connectors would serve two M3s just fine.

30 amps at 240VAC gives the Model 3 22 MPH. Let's assume most people can charge (conservatively) for 12 hours per night. That means, at 240V/30A, a Model 3 would receive 264 miles of range (12x22). Two M3s would split those miles, in some proportion. If one runs a LR M3 from 80% (250 miles range) down to 20% (60 miles range), that is 190 miles. So, one car could arrive home at 20%, the other at 55%, and both would charge back to 80% in 12 hours.

It's hard to imagine a situation where both cars arrive home completely depleted and both must be completely charged in 12 hours or less. Even if each car drove 130 miles a day, this setup would be perfectly adequate.

50 feet of #6 wire, two wall connectors, and labor would probably be under $1500.

 

[lolder]

I'm not sure what you mean by "wired for 30 amps." What voltage? If they are NEMA (X)-30 clothes dryer or water heater outlets, the UMC-2 that comes with the car will charge about 24 miles/hr. (NEMA connector - Wikipedia)

The cheapest is a 230 v 50 A NEMA 14-50
You need $35 adapters from Tesla for both 230 v outlets now.

The UMC-2 that comes with the car is adequate. You can charge from 10% to 90% in less than 9 hours. That's about 240 miles.

 

[Rocky_H]

I'm not sure what you mean by "wired for 30 amps." What voltage?

I think this is one of those things with a lot of new house construction in several states. The builders pre-run a 240V circuit to a garage area for EV charging. Since there doesn't seem to be a very solid spec about how many amps it is required to be, it seems really common that they do a 30 or 40 amp circuit for that connection. It may have an outlet of some kind on the end of it, or sometimes just capped wires with a blank cover plate to let the owner install what they want on the end of it.

 

[azred]

One Tesla charger with the long cord has worked very well for the 16 months since we added our second car. However, when charging the 3, it means running the cable behind the S — and obviously that adds a very slight risk of forgetting and driving over it. But I can’t imagine messing with the needed electrical upgrade to alter our setup. We can add about 45 miles of range per hour to the 3 and 35 to the S, so not surprisingly we have never been short of charging capacity.

The best part is smiling at the line formed at the Costco pumps.