Converting 110 outlets for home charging ?

[eprosenx]

Of course, but you also supposedly aren't supposed to let it sit at 100% so i charge to 90 overnight then bump it shortly before departure. Every little bit helps

I got lucky with my install; the solar installers forgot to charge me for the HPWC install, got a free HPWC from a Tesla referral, and got $500 back from PG&E. So I'm in the black on that one.

On the car, maybe in 20 years

Yeah, my common "leaving town" strategy is the following:

I normally only charge to 80% every night for my daily commute. If going on a trip, I will charge to 90% the night before. Then I do my 30 mile commute, come home, and while packing up the family I see how much range I can regenerate while packing (normally I don't make it back to 100%, but if I can get back to 90% I am doing well).

If I *really* need the range I can pay to use a Chargepoint charger in my garage at work and take it to 90% or even 100% at work, and then plug back in at home to top it up from the 15 mile journey home...

I am a "Boy Scout". I love having the maximum possible options for charging. ;-)

 

[Lschreib]

For some reason, I feel weird having my car charge for that long all night long. I have no reason to feel this way. I’ve been quoted about $950 as the cheapest to get a a 240 install. It’s abour 50 feet of wiring. I’ve been wanting to use the $950 towards PPF

I’ve had my Model 3 about a month and was wondering the same thing. Upgrading to 240 would be quite expensive in my situation, so thinking about skipping it. Does anyone here really know if charging over the long term at 110 will end up being more expensive (in terms of electricity cost) than faster charging at 240? Please don’t reply saying “well the total amount of current consumed is the same”, unless you really know. Many thanks.....

 

[miimura]

I’ve had my Model 3 about a month and was wondering the same thing. Upgrading to 240 would be quite expensive in my situation, so thinking about skipping it. Does anyone here really know if charging over the long term at 110 will end up being more expensive (in terms of electricity cost) than faster charging at 240? Please don’t reply saying “well the total amount of current consumed is the same”, unless you really know. Many thanks.....

Charging at 120V takes longer, so there is more energy consumption from running the overhead items like coolant pumps for more hours. Other than that, it's the same. So, maybe 80% of the wall energy goes into the battery instead of 87%.

 

[Runebane]

One thing to also check is with your electric company. Some are offering rebates if you install a charging station for your EV. I know all the ones in CA are. I would think others would have some sort of incentives as well. That may take some of the sting out of a more expensive install.

 

[n2mb_racing]

I’ve had my Model 3 about a month and was wondering the same thing. Upgrading to 240 would be quite expensive in my situation, so thinking about skipping it. Does anyone here really know if charging over the long term at 110 will end up being more expensive (in terms of electricity cost) than faster charging at 240? Please don’t reply saying “well the total amount of current consumed is the same”, unless you really know. Many thanks.....

Yes, 240 is over 90 percent efficient. 120v is less than 70 percent.

 

[Reid]

One thing to also check is with your electric company. Some are offering rebates if you install a charging station for your EV. I know all the ones in CA are. I would think others would have some sort of incentives as well. That may take some of the sting out of a more expensive install.

PG&E gave us $500 but they just wanted to see that we had an EV. You get it whether or not you install a charging station. (I've got a HPWC on 60a for what it's worth)

 

[Kirby64]

Yes, 240 is over 90 percent efficient. 120v is less than 70 percent.

Model S estimates are 240V charging is closer to 85% efficiency actually.
See:
Measuring EV charging efficiency - Tesla Living

I've heard 120V is around 70% on the nose... I'm certain I've had a source, but can't find it as of right now. The delta isn't that much in terms of actual cost of electricity. Payback time for installing a 220V outlet is usually not actually worth it unless the time scale is many years (>5 yrs) or someone wants the faster charging. Usually the faster charging is the real reason to install one.

If you're a converting an outlet to 220V (to say, a 6-20 outlet), then it probably makes sense because the actual cost is very low. Just an outlet.

 

[miimura]

If you have Time of Use electric rates, the upgrade to 240V charging will definitely pay off. Especially in California where the price differentials are very high.

 

[TexasEV]

If you're a converting an outlet to 220V (to say, a 6-20 outlet), then it probably makes sense because the actual cost is very low. Just an outlet.

220V hasn't been a thing since radio was AM and television was black and white. It's 240V. Also beware that you can only convert a 120V outlet to a 240V one if it's the only one on a circuit, which isn't found often.

Really people should just consider installing a new 240V circuit (NEMA 14-50 outlet unless the house can't handle the load) as part of the price of buying the car.

 

[Kirby64]

220V hasn't been a thing since radio was AM and television was black and white. It's 240V. Also beware that you can only convert a 120V outlet to a 240V one if it's the only one on a circuit, which isn't found often.

Really people should just consider installing a new 240V circuit (NEMA 14-50 outlet unless the house can't handle the load) as part of the price of buying the car.

You're assuming people own a house or are in a place where they plan on living for a long time. Anyone renting is going to be throwing away a considerable amount of money if they pay for an electrician to install a 14-50, since usually renters leave after a couple of years.

Also, if you have a garage, it's possible that there may be only a few outlets in there that are on one circuit. Some might only have one. If you're only losing one outlet, it might be worth it to switch it over to a 6-15 or 6-20.

 

[miimura]

You're assuming people own a house or are in a place where they plan on living for a long time. Anyone renting is going to be throwing away a considerable amount of money if they pay for an electrician to install a 14-50, since usually renters leave after a couple of years.

Also, if you have a garage, it's possible that there may be only a few outlets in there that are on one circuit. Some might only have one. If you're only losing one outlet, it might be worth it to switch it over to a 6-15 or 6-20.

All other 120V outlets on a circuit converted to 240V should be removed and blanked over.

 

[Kirby64]

All other 120V outlets on a circuit converted to 240V should be removed and blanked over.

Obviously the 120V outlets would need to be removed. That being said, is there a NEC code against having 240V outlets daisy chained together? Obviously you shouldn't run both at the same time, but from a usability standpoint (e.g., you want your UMC to reach from both sides of the garage and maybe you don't always use the same side), it could be useful to replace both outlets with 6-15 or 6-20's purely from a flexibility perspective.

 

[Cosmacelf]

Obviously the 120V outlets would need to be removed. That being said, is there a NEC code against having 240V outlets daisy chained together? Obviously you shouldn't run both at the same time, but from a usability standpoint (e.g., you want your UMC to reach from both sides of the garage and maybe you don't always use the same side), it could be useful to replace both outlets with 6-15 or 6-20's purely from a flexibility perspective.

I believe 240v outlets need to be on dedicated breakers (circuits) by code. You can’t daisy chain them together like you do for 120v outlets.

 

[GPinzone]

I believe 240v outlets need to be on dedicated breakers (circuits) by code. You can’t daisy chain them together like you do for 120v outlets.

Yes, but... I have a 14-50 in my garage and directly on the outside to the same line. Yes, I must NOT connect two cars at the same time, but that's okay as I only have the one Tesla.

 

[davewill]

Yes, but... I have a 14-50 in my garage and directly on the outside to the same line. Yes, I must NOT connect two cars at the same time, but that's okay as I only have the one Tesla.

I thought it was finally figured out that it was allowable to have more than one outlet on a 240v circuit. I could be wrong, though.

 

[Rocky_H]

I believe 240v outlets need to be on dedicated breakers (circuits) by code. You can’t daisy chain them together like you do for 120v outlets.

I thought it was finally figured out that it was allowable to have more than one outlet on a 240v circuit. I could be wrong, though.

You're both getting half the story right. The old version of the code for general purpose 240V circuits did allow for multiple outlets on the same circuit. With the 2017 addition of the 625 section that was all about EV charging, it got very specific, and it forbid that. It says that any outlet installed for the purpose of EV charging must be the only outlet on that circuit. Some states have adopted the 2017 NEC version and some haven't, and some have modified it a bit for the version they are adopting.

 

[derotam]

You're both getting half the story right. The old version of the code for general purpose 240V circuits did allow for multiple outlets on the same circuit. With the 2017 addition of the 625 section that was all about EV charging, it got very specific, and it forbid that. It says that any outlet installed for the purpose of EV charging must be the only outlet on that circuit. Some states have adopted the 2017 NEC version and some haven't, and some have modified it a bit for the version they are adopting.

I love the loophole in there though... I just won't install that outlet "for the purpose", it will be another purpose and then later I will decide that hey I should use one of those outlets to charge my car! haha

 

[Kirby64]

You're both getting half the story right. The old version of the code for general purpose 240V circuits did allow for multiple outlets on the same circuit. With the 2017 addition of the 625 section that was all about EV charging, it got very specific, and it forbid that. It says that any outlet installed for the purpose of EV charging must be the only outlet on that circuit. Some states have adopted the 2017 NEC version and some haven't, and some have modified it a bit for the version they are adopting.

Sounds to me like an outlet that is a NEMA 14-50 would by definition fall under 'general purpose' outlet. If I installed a circuit with a wall connector on it, then it's now explicitly for EV charging. So, don't have 2 wall connectors (or a Tesla UMC and some J1772 EVSE) connected without a way to limit current between the two of them.

I found the Article 625 stuff and I don't see anything there that seems to forbid a standard outlet from serving double duty...the wording all seems to apply to stuff like the EV chargers (EVgo, chargepoint, etc etc) since it's all hardwired.

 

[Rocky_H]

Sounds to me like an outlet that is a NEMA 14-50 would by definition fall under 'general purpose' outlet.

No--not by definition. People install outlets for different purposes, so you do have an intention for it when you are installing it, so they aren't always general purpose. However, having a code requirement that depends on the owner's "intention" is just generally flaky. How do you really enforce code on what someone's thoughts are? It's like in Utah, where you can't just order alcohol by itself; you have to have the "intention" to order food also. Mmmmkay. I was "intending" to get some cheese sticks, but I changed my mind.

I found the Article 625 stuff and I don't see anything there that seems to forbid a standard outlet from serving double duty...the wording all seems to apply to stuff like the EV chargers (EVgo, chargepoint, etc etc) since it's all hardwired.

Here you go--the exact citation is 625.40, and it is really crystal clear on this:

"625.40 - Electric Vehicle Branch Circuit. Each outlet installed for the purpose of charging electric vehicles shall be supplied by an individual branch circuit. Each circuit shall have no other outlets."

Charging 2 Teslas in a sequence

 

[Kirby64]

No--not by definition. People install outlets for different purposes, so you do have an intention for it when you are installing it, so they aren't always general purpose. However, having a code requirement that depends on the owner's "intention" is just generally flaky. How do you really enforce code on what someone's thoughts are? It's like in Utah, where you can't just order alcohol by itself; you have to have the "intention" to order food also. Mmmmkay. I was "intending" to get some cheese sticks, but I changed my mind.


Here you go--the exact citation is 625.40, and it is really crystal clear on this:

"625.40 - Electric Vehicle Branch Circuit. Each outlet installed for the purpose of charging electric vehicles shall be supplied by an individual branch circuit. Each circuit shall have no other outlets."

Charging 2 Teslas in a sequence

Ah, there it is. Somehow I managed to overlook the 'no other outlets' part. Still, sounds to me that I could need a 14-50 for powering a compressor... a welder... who knows how many things I might need connected to it. Just so many power tools that need lots of juice besides my car.