Stupid Home Charging Questions

[DB-Cooper]

You adjust it, then plug it in. That would be silly to have to plug it in, then run around and figure out how to adjust it before it tripped the breaker. The adjustment is only grayed out if you are Supercharging.

You don't need to worry about adjusting it anyway. Using the UMC's NEMA 14-50 adapter will automagically set it for you, unless you want set it below 32 amps.

And no, you shouldn't use a 50A breaker in a 50A subpanel.

My electrician advised me accordingly and said since I might run power from the main one day, it wouldn't hurt to use the 14-50 now and bring in a new supply since the car maxes at 32A anyways. He advised that given that, it's totally fine to use the 14-50. I could've installed a different receptacle, but using anything but a 50A on a 14-50 is a code issue in itself, but for this use case, totally fine since it can be controlled. He also stated the wiring used is rated and designed for 50A continuous and closer to 60A for short periods of time, he also inspected the overall quality of the connections and said the breaker is in great shape. He also said I could consider putting a 60A breaker on the main to allow for temporary over-usage but he felt given 32A max and 18 left over, it'd be highly unlikely I'd ever trip with the loads I have. I may put a donut meter on it and see how things go. I appreciate all the arm-chair electrical feedback. I won't lose any sleep over it.

 

[JTwo]

I’m not sure of your daily usage but maybe you could schedule to charge your during the hours your appliances aren’t likely to be used? I have my charge schedule to begin at 12:00am which insures no appliances will be in service and the rates are cheaper.

 

[intelligator]

Glad you got it sorted out.

I have a question regarding the Gen 1,2 UMC. Our LR AWD 3 isn't here yet. My (mis)understanding was that the car could charge to 80% on a 14-50, at 40a with 6 gauge >>> with correct rating <<< but safer on 4 gauge. I don't want to go over the wire aspect of the puzzle, I'm not an electrician and have one to help with our charging setup when ready. ABout the kit, why is the Gen2 reduced to 32a from theoretical max of 40a on a 50a outlet? I'll go find the documetns that explain each - just learning of the Gen1/2 UMC now.

 

[BerTX]

My electrician advised me accordingly and said since I might run power from the main one day, it wouldn't hurt to use the 14-50 now and bring in a new supply since the car maxes at 32A anyways. He advised that given that, it's totally fine to use the 14-50. I could've installed a different receptacle, but using anything but a 50A on a 14-50 is a code issue in itself, but for this use case, totally fine since it can be controlled. He also stated the wiring used is rated and designed for 50A continuous and closer to 60A for short periods of time, he also inspected the overall quality of the connections and said the breaker is in great shape. He also said I could consider putting a 60A breaker on the main to allow for temporary over-usage but he felt given 32A max and 18 left over, it'd be highly unlikely I'd ever trip with the loads I have. I may put a donut meter on it and see how things go. I appreciate all the arm-chair electrical feedback. I won't lose any sleep over it.

We mean well

We had some electricians contributing here for a while, but they probably got frustrated and went silent.

And you could have led off with the fact that you had an electrician do the work and saved us all some time

 

[ai4px]

Thinking outside the box here... if you are DIY minded, get a Smart EVSE controller. It can certainly be wired to a Tesla plugend or you can use a J1772 adapter. Never the less, the Smart EVSE has an optiona current transformer available that will allow it to dynamically adjust charge current based on how much current something else is using. You could for example place the current sense transformer on the main feed into your house and if the current got above 100 amps, it would throttle back the car charging. In my application I’ve gutted a Siemens Versicharge used for my Bolt and have placed the current transformer on the Tesla charger’s feed. When wife’s car is charging, the Smart EVSE limits how much my Chevy Bolt can draw. It really works well. I used twisted pair wire to run the current transformer leads around 3 walls of my garage and it works great despite the distance.

 

[nvx1977]

wow such complicated responses from such a simple situation. As has been said, your gen 2 cable will have the car pull 32A. You're fine on sizing.

You might even intentionally set it to 24A for a bit more efficiency from the wall. You can set the amperage draw from the car any time. No need to plug in and then run in the car to do it before charging ramps up. Where does this misinformation even come from??? I can vouch this works for both S and 3.

If you do run into a situation where your subpanel trips, then schedule your charge to take place when you're unlikely to be drawing anywhere else in your house, like when you're asleep. Now that it's winter, I have my charging start at 5am, at 24A. That gets me full or near full by the time I'm ready to head out. Batteries are also warm, so I have full regen.

 

[DB-Cooper]

Thanks all, yeah I should've said electrician out the gate, I initially told him about the 50A on 50A and he said, "look, if you want the 14-50 because you have the connector and flexibility down the road, go for it. Your house won't burn down and you can adjust the charging rate at the wall charger or at the Tesla." I've used this guy for years, I own a lot of property and have used him, certain things I'll have him do by the books, others I ask, "How would you do it in your home." He's a master electrician, in his 60s and continually educates me on electricity and is well studied on the stuff. I had initially asked him to use a smaller breaker on the 14-50 and he adamantly said he won't do that for other now obvious reasons...

I am probably going to install a Sense system on my main soon, but debating whether to put it on my sub as it might give more insight to the car charging limitations, but at the risk of losing better insight as well as monitoring of the solar system (which SolarEdge does way better anyways). On the fence there, not sure how well Sense can see items downstream from the main through the sub. I doubt it can detect the sub itself and would blur the usage amongst a handful of things on my main like exterior lights. Most of my kitchen doesn't go through the sub, so I'd lose a lot of insight in addition to AC usage.

As far as scheduling the charge, our peak usage is 530-730pm when we're cooking, lots of lights on, etc. Given that we'll mostly charge for free at my wife's work, I'll probably charge if needed late at night (midnight to 6am) or during mid-day when actually usage is very low (no lights, no TVs, no dishwasher/microwave/etc. I work from home and could see the need for a quick top-off if we suddenly need to run to Houston, but honestly I bet we'll charge once or twice a month. We drive only 7,500 miles per year and my wife works 5 days a week at a place with free ChargePoint. Initially I was excited about the gas savings, but all that money is diverted to the insurance premiums, All State charges twice for this car as a late model M3 or my other current car a Cadillac ATS-V; now venting...