Least expensive charging option better than 110

[bwilliams]

What might the least expensive option be for charging my MY that's better than 110V, 15A? I'm likely selling my home and had planned to use local plugshare options but I've decided riding my bike back and forth is unreasonable - especially in the rain (the closest plugshare is 15 miles; no superchargers within reason). I have an electric dryer outlet that I can give up (I have a gas dryer available) but the distance to the car is 60 feet. The distance from the closest side-of-house is 30 feet. If it's possible to run a line below the deck then 15 feet. There is no garage and I don't want to pay for trenching to the driveway for sure. Obviously I am not an electrician. Ideas?

 

[dhrivnak]

A NEMA 5-20, needs a dedicated 20A breaker and 20A rated outlet gives me about 7 miles/hour, or a good 70 miles overnight. Many outlets are wired with the required 12 gauge wire.

 

[exxxviii]

Well, anything 240V is better than anything 110V. And anything you already have is better than anything you might install.

The dryer outlet is probably your best bet. But, I think extension cords are a no-no for stead EV charging. One option... you could install a hardwire extension run from that dryer outlet to the garage and then mount another 14-50 outlet in the garage. You would just need to get approved wire and conduit (if needed).

 

[Sophias_dad]

You could maybe upgrade the 120V outlet to 240V, but you'd have to be sure there were no other outlets on that circuit. As was mentioned, you might also have the ability to install a 20A outlet on the current 120V line(in fact it may already be 20A, check if one of the two spade holes is actually T shaped, which indicates its 20A).

 

[ATPMSD]

IF the 120v outlet is dedicated, and there is nothing else on the circuit, you can convert it to 240v. You will need to replace the outlet with a NEMA 6-15 outlet, purhcase the Tesla 6-15 adapter and replace the single-pole breaker with a dual-pole 15A GFIC breaker. This wiill more than double the charging speed.

If the existing breaker is 20A instead of 15A, just use a 6-20 outlet, adapter and 20A GFIC breaker.

 

[thefrog1394]

50 amp extension cord. You'll need a 6-50 adapter on the car side and a dryer outlet (14-30 or 10-30) to 6-50 adapter on the dryer side. Dryer outlets are typically 30 amps, so you'll want to crank the amperage on the car side down to 24 amps maximum.

You could also use a 30 amp rated extension cord, but it's harder to find those with compatible plug ends. something along these lines. Then you'd use the 10-30 adapter on the Tesla side as well. This is a little bit safer because the car won't physically let you select more than 24 amps.

Just keep an eye on the dryer-outlet side for any signs of failure (melting). It would typically be the dryer plug itself that would fail. To be extra safe, charge at 20 amps instead of the full 24.

Extension cords aren't recommended for permanent use, but if this is a few months to a year while you sell your house, it shouldn't be a problem if you keep an eye on it. Careful about damaging the cord (eg repeated slamming of a door on it), and pull the dryer outlet side and look for signs of failure every so often.

 

[ATPMSD]

install a hardwire extension run from that dryer outlet to the garage and then mount another 14-50 outlet in the garage

If you do this, which I would not recommend, you will need a 14-30 outlet, not a 14-50, Dryers use a 30A circuit.

 

[exxxviii]

If you do this, which I would not recommend, you will need a 14-30 outlet, not a 14-50, Dryers use a 30A circuit.

Good point. For some reason, I just had 15-30 on my brain when I wrote that.

But, why wouldn't you recommend it, if you put a proper junction box at the current outlet and properly routed the cabling to the new location?

I also like the idea of converting the existing 120V to 240V, assuming no other outlets are on the circuit.

 

[ATPMSD]

Good point. For some reason, I just had 15-30 on my brain when I wrote that.

But, why wouldn't you recommend it, if you put a proper junction box at the current outlet and properly routed the cabling to the new location?

I also like the idea of converting the existing 120V to 240V, assuming no other outlets are on the circuit.

You used the term “extension” which is a red flag. If you want to hardwire from the outlet (better yet from the breaker box) to a permanent exterior outlet, that will work. Keep in mind the mobile connector is not rated for wet environments, so you will also need some sort of box for it. I suggest this is not a DIY project and that you should engage a electrician. You will also need a GFIC breaker if one is not already installed for the dryer.

 

[jcanoe]

If the current 5-15 receptacle that you are using to charge your Tesla Model Y is the only receptacle on that 15 amp circuit (no other lights or receptacles) on the circuit then an electrician can easily rewire the circuit to be 240V and 15 amps. The receptacle would be changed to a 6-15R. Changing to 240V from 120V would double the available power from 1.4kW to 2.8kW and halve the charging time.

Although extension cords are not recommended and should only be considered a temporary solution you could purchase a 50 foot length 10 gauge extension cord with either the older spec 10-30 dryer plug or the newer spec 14-30 dryer plug, up to 50 foot length, on Amazon. The Tesla Mobile Connector charging cord plus Mobile Connector plug adapter and chassis is ~20 feet in total length. The total length of ~70 feet might be long enough to enable you to charge your Tesla Model Y.

 

[thefrog1394]

You used the term “extension” which is a red flag. If you want to hardwire from the outlet (better yet from the breaker box) to a permanent exterior outlet, that will work. Keep in mind the mobile connector is not rated for wet environments, so you will also need some sort of box for it. I suggest this is not a DIY project and that you should engage a electrician. You will also need a GFIC breaker if one is not already installed for the dryer.

GFCI may not be required on an outdoor 250v receptacle. That was added to NEC in 2020, so depends which version your locality is using.

From a practical perspective, the mobile connector has GFCI built in, so as long as you aren't plugging/unplugging the mobile connector itself, it's not a shock hazard.

I've heard GFCI in front of the wall connector can cause nusiance trips. I pulled mine from my outdoor 50 amp GFCI and replaced with a regular 50 amp breaker because of that (although it was an Amazon return, so might have been a faulty breaker). Another option would be hardwiring a wall connector on a 4x4 post which would not require GFCI.

This is all getting much more involved than a temporary install though, at which point just doing it right and trenching to the driveway and installing on a pedestal would make the most sense.

 

[ATPMSD]

GFCI may not be required on an outdoor 250v receptacle. That was added to NEC in 2020, so depends which version your locality is using

Not entirely true. Before the 2020 Edition the code required GFIC for all EV charging. The 2020 change made that part of the code moot.

From a practical perspective, the mobile connector has GFCI built in, so as long as you aren't plugging/unplugging the mobile connector itself, it's not a shock hazard.

Disagree. The GFIC in the mobile connector protects the connection from the connector to the car. The one required by code protects the outlet.

I've heard GFCI in front of the wall connector can cause nusiance trips.

Such trips indicate a problem with the GFIC breaker or there is a leak somewhere in the wiring. Replacing it with a standard breaker does not fix the underlying problem. Of course, this is the owner’s decision.

 

[davewill]

Have you gotten any quotes? How much do you drive on a daily basis? How soon are you planning to sell?

If you're not there long and the 120v outlet meets your daily needs, you might want to just keep using that.

If the time is short, but 120v ISN'T adequate, then I'd say you want 240v/30a at a minimum. Anything less should only be because more would be cost prohibitive. Speaking of costs, also get quotes for doing a full 50a or 60 circuit. The price may not be all that different if the run ends up short enough.

Here's the deal, 240v 20a charges about 3 times faster than your current 120v/15a plug. You can look at the following table to help you make up your mind (I added the 120v 15a row for comparison):

Charge Speed
Max miles of range per hour of charge

Circuit breaker (amps)	Outlets	Maximum output (amps)	Power (kilowatt)	Model S (mph)	Model 3 (mph)	Model X (mph)	Model Y (mph)
60		48	11.5 kW	41	44	35	44
50	6-50, 14-50	40	9.6 kW	34	37	29	37
40	6-50, 14-50	32	7.7 kW	27	30	23	30
30	6-30, 14-30	24	5.7 kW	21	22	17	22
20	6-20	16	3.8 kW	14	15	12	15
15	6-15	12	2.8 kW	10	11	9	11
20 (120v)	5-20	16	1.9 kW	7	7	6	7
15 (120v)	5-15	12	1.4 kW (120v)	5	6	4	5

 

[bwilliams]

Thanks for all the input everyone. I need to take notes to see what might work best for me. I will be hiring an electrician - no wiring for me. Too much at risk for that. I don't have a garage, fwiw. Living here in the NH woods means lots of driving to get to just about anywhere - at least by my standard where in CA grocery etc is 2 miles away. It does seem the 14-30 would be adequate though.

 

[Level8Drummer]

At home I have a wall connector that is wired to do 48a 240v, with 6 gauge wires and a 60a breaker. Even though I have all of that juice, when charging overnight I limit my charge speed to 15a 240v, which is about 3.6kw. It's plenty for us as long as we plan ahead a little...like don't run it down to 10%, start charging at midnight and hope to have it charged up to 90% for a road trip at 8am lol. You may do just fine converting to 15a at 240v. Would be a cheap and likely satisfactory option, considering the price of copper right now...

Wouldn't you want a 20a breaker to charge at 15a?

L8d

 

[ATPMSD]

At home I have a wall connector that is wired to do 48a 240v, with 6 gauge wires and a 60a breaker

If the #6 wire happens to be Romex, you cannot charge at 48A, you should reconfigure the wall connector to a 50A circuit. Romex is rated at 55A and can support a continuous load of only 44A.

I limit my charge speed to 15a 240v

It is more efficient to charge at the maximum speed availably, so it is costing you more money to charge in this way, and using the maximum rate eliminates having to “plan ahead.” Also, limiting the rate using the setting in the car is not recommended except as a temporary solution. There is no guarantee the car will not forget the setting and revert to the maximum setting in the wall connector. In the case of a wall connector set to 60A and Romex wire, it will exceed the wire’s rating.

 

[Level8Drummer]

Thanks for the info, it's 6g copper wire as Tesla specifies.

 

[Sophias_dad]

Thanks for the info, it's 6g copper wire as Tesla specifies.

I think you are missing the point. 6 gauge copper in conduit is fine for 48 amps continuously. 6 gauge copper in NM cable(aka Romex) is not okay, since the NEC says it can only be used up to the 60C rating(55 amps, times 0.8 for continuous(EV) use, which gets you to 44 amps)

 

[Level8Drummer]

Yep! I gotcha. I'm good then. Thanks!

 

[Level8Drummer]

I don't know why you both got on a Romex kick. I was just saying that home charging at 3.6 kw (15a/240v) works well under normal circumstances for me.