Home Charging Setup

[bakerboy]

It's going to be another 4-5 weeks before I get my 2013 MS P85 CPO, so I'm weighing all of my options for home charging now. I've been doing a lot of reading on here and think I know what direction I'm gonna go in, but could still use some insight. So I'm not to keen on "electrical" lingo but I will describe my current setup at home and see what everyone thinks. I have an electrician coming to my house on Monday so I would like to give him as much info as possible.


Here is a very quick graph of my garage, where I will be parking the car, where my main and sub panel in my garage are. I have also pointed out where my 14-30 dryer connection is just in case.




Here is my main panel (notice the 220 breakers for the dryer connection that is not being used and the pool pumps):



Here is the sub panel in the garage:







The sub panel is in the corner of the garage:




Here is the area between my garage doors:





So my plan is to put a 14-50 plug on the wall in between the garage doors because as you can see from the quick drawing the Tesla will be parked reversed in so the access port will be close. I do plan on getting an HPWC within a year, once I get that I can just plug the HPWC directly into the 14-50, also once my wife's lease on her Infinity is up (3 years, just got it) we will be getting another EV. I will be asking the electrician to run wires from the sub panel in the garage up over the 2 car garage door and drop down in between the 2 doors, does this sound realistic? What info should I tell him? I was thinking about a 50 Amp breaker, is that right?

Thanks!

 

[CalBlue 85D]

50 amps is fine for one car overnight. Since you are looking at two EV's in the near future, I'd recommend running a 100 amp service to give you more options for faster charging / two cars. Depends on if your garage panel can support it.

 

[ColdRauv]

Looks like you only have a 100 service. Might not be possible to add a 50A circuit.

 

[bakerboy]

Looks like you only have a 100 service. Might not be possible to add a 50A circuit.

You're talking about the sub panel in the garage?

 

[gregd]

I think he's referring to the main panel, which appears to be only 100 amps total. Adding yet more load to that will likely be a problem. I had a 125A service, all slots full, and needed to upgrade to 200 amps when I added a 14-50 in the garage. In addition to the main panel, I can't make out what the subpanel is wired for. The wire gauge between the two might be your limiting factor, even if the main panel isn't.

Also, what brand is the main panel? If it's a Zensco or similar, you should upgrade it in any case, as it's considered a fire hazard.

All that said, the easiest solution in the short term would be to use the unused 14-30 dryer outlet, and dial down the charging to 24 amps. I did this for several years, before opting to do the 14-50 plus panel upgrade in order to take advantage of the tax credit that expired at the end of last year. (My panel was a Zensco, which offered an increased sense of urgency once I found out what the issue was.)

 

[bakerboy]

Oh ok! I'll get the detailed info tonight, how did you use the unused 14-30 and dial it down?

 

[bakerboy]

By zooming in on my main panel, there is a sticker next to the 100 breaker for "service disconnect" so I assume I do have a 100 Amp service. A little background: I moved into this house about 1yr 4months ago, it was built in 89, 2 story, we have a gas dryer and a built in swimming pool w/ 2 pumps and central AC and heat.

We currently do not have solar panels, I'm really considering going solar, when we go solar, do they install a new panel?

 

[gregd]

Oh ok! I'll get the detailed info tonight, how did you use the unused 14-30 and dial it down?

There are several ways to do this. If you are going to be using a Tesla wall charger, there are settings inside that tell the unit what sort of circuit it's connected to. Be sure not to get confused between the Breaker value (30 amps) and the resulting charge value (80% of 30 amps, which is 24 amps). Car charging (any continuous load, for that matter) is limited to 80% of the breaker value by the National Electric Code. I think the Tesla unit is configured for the breaker, but check first. If you are using the UMC (the "mobile adapter"), try to get the 14-30 pigtail for it. That will automatically set the UMC to 24 amp charging.

The other way is to tell the car what the maximum charge rate is, and the car should remember it for your location. Software updates to the car can reset this, so be careful.

My own situation was actually the older 10-30 style dryer outlet, and I purchased the 10-30 UMC pigtail. I also used a home-built extension cord in order to reach the outlet, and told the car (a Roadster in my case) to limit to 24 amps. Belt and suspenders; worked perfectly every time.

 

[bakerboy]

Ok, my 10-30 outlet is about 40' total from where its at to where I would need it to be.

(I don't know why I put 14-30 on my diagram)

Here is the plug located behind my dryer:

 

[DarkMatter]

If you don't mind running between there and the car location, you could build a 10-30 extension cord and buy an adapter. More realistically you probably need to talk to an electrician. Your garage sub panel does not have enough room for another 220 breaker but your main panel will after pulling that 10-30 outlet.

 

[bakerboy]

Ok!

I have a co-worker that has 2 EV's and thats what he told me, that I should be able to "cancel" the 10-30 dryer plug and use that?

 

[gregd]

Ok!

I have a co-worker that has 2 EV's and thats what he told me, that I should be able to "cancel" the 10-30 dryer plug and use that?

Essentially, yes. But it's still a 30 amp (24 amp charging) circuit since it's probably wired with #10. Tesla doesn't appear to sell a 10-30 adapter for the Model S/X, so you can't use the UMC without making or finding a custom 10-30 to 14-30 adapter. Best is to have an electrician wire the wall charger to the circuit, and set it for the 30 amp circuit. If he/she can verify that the wiring is good enough, you might be able to squeeze the extra 20 amps and upgrade to a 14-50. Really depends on what you have inside the walls, but regardless, you're pushing it with the 100amp overall service. That one car is a third to half the entire house. Air Conditioning is usually on a 50 amp circuit, so that's the other half. Then you want to fire up the microwave oven, toaster oven, or ...? 100 amps goes by really fast.

 

[DarkMatter]

And 100 amps isn't really 100 amps. If you have a 40 amp continuous load on it (like car charging) then that portion needs to be derated to 80%, meaning it actually allocates 50 amps.

 

[BerTX]

Sorry to say, but you need to have all that rats nest sorted out by an electrician. But lets try to figure out what you can do in the meantime.

So let's back up a bit about your current configuration.

The labeling is totally -um- unreadable. Somewhere you have a 240 breaker in the main panel that feeds the garage. You have labels in the main box that are labeled for the dryer as well as the same one for the pool. Then in the garage box, you have some labeled for the pool.

My guess is that the breaker labeled for the dryer/pool is actually feeding the garage sub-panel? I don't think you have a dryer outlet to steal for charging -- I think that is already stolen and running your pool. Can you identify which circuit is running the pool?

I see something in the main panel about the garage, but it looks to be a small 120v breaker.

My guess is that 1) this was all done by an amateur some time ago 2) the garage lights and outlets used to be wired directly from the main panel, 3) when the pool was put in, they took the breaker that was feeding the dryer outlet and took that to the garage sub-panel That would mean you just have 30A feeding the pool and whatever outlets and lights are in the garage.

I don't think your main panel has enough capacity for charging, the sub is not to code and will need replacement, and the best you can do is to charge your new car at 4 mph from a 120v outlet. Unless you want to give up the pool.

Sorry, but this is going to be expensive.

 

[SMAlset]

If you can swing it now, I'd say have your service upgraded so you can plan now for service for both cars and anything else you might add later. One less permit you'll need to pay for at some point in time. When our house was being built in the early 1990s the developer's standard was 200A service but they offered an upgrade to 300A. At the time hubby thought 200 would be fine even with computer equipment, tv, etc. Didn't plan a pool, hot tub or use of heavy equipment and we had a little space left in our panel. Since that time we ended up remodeling our kitchen with more appliances, added outdoor structures and electrical and a patio heater. Now that we have gone EV our Tesla on a 14-50 just made it but we'll have to do something should we replace my old ICE with an EV. In retrospect we should have gone 300A.

As for the electrical panel box, I remember hearing there was a brand that you definitely didn't want installed. Ask your electrician for his advice on what you have.

 

[Tam]

Ok, my 10-30 outlet is about 40' total from where its at to where I would need it to be.

There's a 50ft extension for $158.12

Steambrite Supply

 

[CmdrThor]

There's a 50ft extension for $158.12

Steambrite Supply

You wouldn't need a 50' extension. The UMC cable has a 20' cable. Basically he would need a 25' extension that has a 10-30 plug and a 14-30 receptacle. It would need to be marked Tesla Charging Only. I bought this cable to make a 25' 14-30 extension for $30, but it isn't available at Home Depot anymore.

Cerrowire 25 ft. 10/3 600-Volt Black SOOW Cord-283-3803A - The Home Depot

It has an extra wire he doesn't need, but could easily be wired with the proper plug and receptacle. With only 100A service for the house and the fact he has pool pumps, 24 amps is the max I would be comfortable charging at anyways. The Mobile Connector 14-30 adapter was just made available again so I think that is the way to go.

 

[bob_p]

In the 4 years we've had our S P85, I've lived in 2 houses and a townhouse. Most of the time I used an HPWC on a 100A circuit with the dual chargers in the P85. And for short periods, I was using a 14-50 outlet with the UMC.

Our current house has a 100A HPWC on one wall and a 14-50 outlet on the other wall.

When our S 100D arrived last week (with only the standard 48A charger), we moved the S P85 over to the side of the garage with the 14-50 outlet and instead of ordering an HPWC, we ordered Tesla's 14-50 charging cable. An HPWC is overkill on a 50A circuit - the 14-50 cable is slightly cheaper to purchase from Tesla and much easier to install (just plug it in).

The S 100D will use the HPWC, but only draw 48A.

When ordering the S 100D, I reviewed our charging of the S P85, and decided there wasn't any need to order the 72A charger upgrade - and really no need to have the S P85 charging at 80A. Because in 4 years, I can only recall needing to do a fast charge once - and that was after commuting to/from work during the day before heading out on a road trip in the evening - and that was before there were any superchargers. After superchargers were installed on the major highways - there hasn't been any need to charge quickly at home - so really no need to charge at more than 40 or 48A at home, when charging is usually done overnight.

If we move again (which I hope won't be for a long time), I'd probably stick with 14-50 outlets - for each garage parking spot, and not bother with the more complicated installation of an HPWC on the walls.

 

[bakerboy]

Thank you everyone for your input, I really appreciate it!!!

If I was to get solar for my house, do they still use my existing panel or do they bypass the panel, or do they install a new panel?

 

[miimura]

Thank you everyone for your input, I really appreciate it!!!

If I was to get solar for my house, do they still use my existing panel or do they bypass the panel, or do they install a new panel?

If you're going to get solar I would have the main service and panel upgraded and all the wiring completely straightened out in the same job. That way you can take the 30% ITC on the upgrade cost.