NEMA14-50 question

[relaxjim]

Aloha, I'm offgrid 6.1 KW array capable of 25 amps max. 3 questions: I'm having a Nema14-50 outlet installed, will the cable that comes with model 3 connect to that?
the other question is that I'm being told I must limit the draw on my system to 20 amps max. can you set the model 3 to only draw 20amp max? Trying to get this dialed in before the M3 arrives next month. Also wondering if an EVDuty Smart Current sensor would help
Mahalo!!

 

[Gauss Guzzler]

Yes, you can limit the charge rate thru the app or touchscreen and the car will permanently remember that setting at that location, but the setting can easily be undone by people, software updates, hardware replacements, etc.

Consider a cheaper/smaller/easier 6-20 outlet instead of 14-50 since you're limited to 20A anyway. Then the hardware will set your charge limit and you needn't mess with anything.

Most cars don't come with a charger anymore. So if you end up buying the charger separately, consider the wall charger instead. It's a better system and ends up being nearly the same price in the end. The wall charger can do 48A but can be hardware-configured all the way down to 12A if you need.

 

[3sr+buyer]

Recent Model 3 may not come with the mobile connector. If your car came with a mobile connector, a 14-50 plug adapter (or any of several other plug adapters) costs about $45 each. If your car did not come with a mobile connector, it is $200 (and may or may not include a 14-50 plug adapter).

By default the mobile connector with 14-50 plug will tell the car that it can draw 32A (different plugs may cause the mobile connector to tell the car different amperages). You can tell the car to limit the charge rate to a lower amperage (maximum 32A for standard range, 48A for long range).

If you do not want to depend on the setting in the car, you may want to consider other outlet and plug options with the mobile connector:
* 6-20 -> 16A
* 14-30 -> 24A

There are other EVSE options (e.g. Tesla wall connector (which is hardwired, no outlet needed), Grizzl-E) where you can set the maximum charge rate to 16A or 24A. There is also a Clipper Creek LCS-25 which is a hardwired EVSE that does 20A maximum.

 

[Rocky_H]

the other question is that I'm being told I must limit the draw on my system to 20 amps max.

Then you shouldn't be using a 14-50 outlet at all. You need to put in a lower level circuit that will force compliance with that 20A limit. That can be either with a wall connector or with an outlet, but you shouldn't be putting in something that is too high and relying on having the amps manually turned down on the charging screen in the car.

 

[threeputts]

Are you buying new? When did you order? Hopefully you are aware that no cable "comes with" a new model 3 now (you didn't say if you were buying new or not). If new you should have had the option to select a mobile connector or wall charger when you ordered the car if it wasn't included (cutoff order date for inclusion was late April IIRC).

If the 14-50 installation hasn't started I would change it to 6-20 as others have said. If you get the mobile connector the 6-20 adapter is $35. If the outlet is already there you can select a mobile connector that includes a 14-50 adapter or buy the $45 14-50 adapter seperately.

No matter what you do I would order your charging setup now as everthing has been going out of stock frequently.

 

[RayK]

Aloha, I'm offgrid 6.1 KW array capable of 25 amps max. 3 questions: I'm having a Nema14-50 outlet installed, will the cable that comes with model 3 connect to that?
the other question is that I'm being told I must limit the draw on my system to 20 amps max. can you set the model 3 to only draw 20amp max? Trying to get this dialed in before the M3 arrives next month. Also wondering if an EVDuty Smart Current sensor would help
Mahalo!!

Curious.... is the 20A maximum current during the day when the panels are near their maximum output, or is this at night when your (assumed) battery storage takes over?

I would also echo the previous advice you received here that you install a 6-20 (240V 20A) outlet. That forces you to use a Tesla NEMA 6-20 adapter for the mobile connector that will limit itself to 16A. You'll be getting a charge rate of about 15 miles per hour when using the 6-20 outlet.

 

[freeAgent]

Is your total draw on the system 20 amps, or is that 20 amps dedicated to your 14-50 outlet? If 20 amps is for your entire home, I'd be sure to subtract out your household use from that 20 amps. I'm able to use the mobile app to set my charging rate all the way down to 5 amps in 1 amp increments, so you should be ok. Charging is going to be slow, though!

As others have said, Tesla stopped including the mobile charger with their vehicles recently. It's very possible your car won't come with one, so will want to try and purchase one separately. If I was you, I'd confirm with Tesla whether you'll receive one with your car. The mobile connector is out of stock right now on Tesla's website (with a 14-50 plug adapter, it is in stock with a standard 5-15 adapter), so that could get tricky. If it was me, I would get the mobile connector with a 5-15 plug from Tesla and then pick up a 14-50 adapter for it from evseadapters.com (NEMA 14-50 Adapter for Tesla Model S/3/X/Y Gen 2 – EVSE Adapters) or somewhere else.

 

[ucmndd]

Agree with the recommendations to install a 6-20 instead of a 14-50. Don't trust the car's amperage setting to not do something stupid.

 

[relaxjim]

Curious.... is the 20A maximum current during the day when the panels are near their maximum output, or is this at night when your (assumed) battery storage takes over?

I would also echo the previous advice you received here that you install a 6-20 (240V 20A) outlet. That forces you to use a Tesla NEMA 6-20 adapter for the mobile connector that will limit itself to 16A. You'll be getting a charge rate of about 15 miles per hour when using the 6-20 outlet.

It's the max drawing from the batteries. I won't be trying to charge at night as the batteries will drain too far

 

[relaxjim]

Is your total draw on the system 20 amps, or is that 20 amps dedicated to your 14-50 outlet? If 20 amps is for your entire home, I'd be sure to subtract out your household use from that 20 amps. I'm able to use the mobile app to set my charging rate all the way down to 5 amps in 1 amp increments, so you should be ok. Charging is going to be slow, though!

As others have said, Tesla stopped including the mobile charger with their vehicles recently. It's very possible your car won't come with one, so will want to try and purchase one separately. If I was you, I'd confirm with Tesla whether you'll receive one with your car. The mobile connector is out of stock right now on Tesla's website (with a 14-50 plug adapter, it is in stock with a standard 5-15 adapter), so that could get tricky. If it was me, I would get the mobile connector with a 5-15 plug from Tesla and then pick up a 14-50 adapter for it from evseadapters.com (NEMA 14-50 Adapter for Tesla Model S/3/X/Y Gen 2 – EVSE Adapters) or somewhere else.

My electrician says the system is capable of 25 amps ( it's a 48v 6.1kw offered system feeding 4 Simpliphi 48v batteries). I think that's why he said the limit for the Tesla should be set at 20 amps. a friend is lending me her M3 while out of town so I plan to test it, but the electrician is coming Tuesday to install the 240v nema14-50 outlet . I just found out she doesn't have the adapter so I ordered one from Tesla just now.

 

[RayK]

If you are determined to install a 14-50 outlet and also use Tesla's NEMA 14-50 adapter for the mobile connector, you MUST manually adjust the charging current in the car. Supposedly, once you do that the car will remember that current setting. However, I would NOT rely on it to work each and every time. You know, s*** happens from time to time and if the car forgets to automatically change the charge current from the default current (at least 32A), that might overload your electrical system.

 

[ucmndd]

My electrician says the system is capable of 25 amps ( it's a 48v 6.1kw offered system feeding 4 Simpliphi 48v batteries). I think that's why he said the limit for the Tesla should be set at 20 amps. a friend is lending me her M3 while out of town so I plan to test it, but the electrician is coming Tuesday to install the 240v nema14-50 outlet . I just found out she doesn't have the adapter so I ordered one from Tesla just now.

Again, don’t do this. It’s a dumb idea.

If the max you can safely draw from your electrical system is 20 amps, install a 6-20 outlet or a wall connector configured to provide no more than 20 amps.

You don’t need a 14-50. All it does is introduce unnecessary liability.

 

[relaxjim]

My electrician says the system is capable of 25 amps ( it's a 48v 6.1kw offered system feeding 4 Simpliphi 48v batteries). I think that's why he said the limit for the Tesla should be set at 20 amps. a friend is lending me her M3 while out of town so I plan to test it, but the electrician is coming Tuesday to install the 240v nema14-50 outlet . I just found out she doesn't have the adapter so I ordered one from Tesla just now.

pS, the charging cable she's lending me has the 5'15plug, but that's not going to show me what my system is capable of ( I will try it but 3mph won't work. the distances here on Hawaii island are far. Mahalo for your input!!

If you are determined to install a 14-50 outlet and also use Tesla's NEMA 14-50 adapter for the mobile connector, you MUST manually adjust the charging current in the car. Supposedly, once you do that the car will remember that current setting. However, I would NOT rely on it to work each and every time. You know, s*** happens from time to time and if the car forgets to automatically change the charge current from the default current (at least 32A), that might overload your electrical system.

Mahalo Ray, I am planning g to manually adjust the charging rate on the car. Very helpful info to make sure it's set to 20 amp max every time I charge at home. with a total of 25amp headroom, if I set the Tesla to 20 amp max, hopefully it will work. if I get 15mph I'll be thrilled

 

[relaxjim]

Again, don’t do this. It’s a dumb idea.

If the max you can safely draw from your electrical system is 20 amps, install a 6-20 outlet or a wall connector configured to provide no more than 20 amps.

You don’t need a 14-50. All it does is introduce unnecessary liability.

I will definatl

Again, don’t do this. It’s a dumb idea.

If the max you can safely draw from your electrical system is 20 amps, install a 6-20 outlet or a wall connector configured to provide no more than 20 amps.

You don’t need a 14-50. All it does is introduce unnecessary liability.

I appreciate this, and will definitely ask the electrician about this!

 

[RayK]

From your description of your electrical system, putting in a 14-50 outlet is overkill. It doesn't seem like you will ever be able to output the 40A continuous that that socket implies. As previously recommended by others here, installing a 6-20 and using Tesla's 6-20 NEMA adapter will automatically limit the car's intake to 16A. That will get you about 15MPH. You won't have to fiddle around with adjusting the current limit in the car.

The only downside that I can see using a 6-20 outlet versus a 14-50 is that the 6-20 is not as popular. If you do need to plug in something that takes 240V at some "high" current, you may need to change the plug. The upside is that wiring it into your system should be cheaper since the wire gauge would be smaller and you can eliminate one wire that's used in the 14-50 that the 6-20 doesn't have.

edit: The only reason installing a 14-50 would make sense to me is IF you are planning to upgrade your solar system to provide about double the power you are now getting. Putting in a 14-50 now would be useful in that case as you are future-proofing your setup. BUT, you will still need to be very careful that you monitor your charging sessions and make sure the car never asks for more than 20A, each and every time.

 

[MLXXXp]

The only reason installing a 14-50 would make sense to me is IF you are planning to upgrade your solar system to provide about double the power you are now getting. Putting in a 14-50 now would be useful in that case as you are future-proofing your setup.

In that case, I would still install a 6-20 outlet but run 6 AWG wire. This way, the majority of the circuit is future proofed and you'll safely draw only 16A max. To upgrade in the future, only the outlet, and maybe the breaker, has to be changed.

 

[Rocky_H]

but the electrician is coming Tuesday to install the 240v nema14-50 outlet . I just found out she doesn't have the adapter so I ordered one from Tesla just now.

...after we all just told you that a 14-50 is a really bad idea for this?

I am planning g to manually adjust the charging rate on the car. Very helpful info to make sure it's set to 20 amp max every time I charge at home.

It is not that reliable. You should be enforcing this with the configuration of what you install, not with the car's dialed down setting.

My electrician says the system is capable of 25 amps ( it's a 48v 6.1kw offered system feeding 4 Simpliphi 48v batteries). I think that's why he said the limit for the Tesla should be set at 20 amps.

Then maybe a 30A circuit would be a decent idea for this. For car charging, the installations are set to draw no more than 80% of the circuit rating, so a 20A circuit will draw 16A, and 30A circuit will draw 24A. You can turn it down some below that if you want to, but at least setting it up properly will put that real top limit on it, and 24 sounds fairly good for this application.

 

[relaxjim]

...after we all just told you that a 14-50 is a really bad idea for this?

It is not that reliable. You should be enforcing this with the configuration of what you install, not with the car's dialed down setting.

Then maybe a 30A circuit would be a decent idea for this. For car charging, the installations are set to draw no more than 80% of the circuit rating, so a 20A circuit will draw 16A, and 30A circuit will draw 24A. You can turn it down some below that if you want to, but at least setting it up properly will put that real top limit on it, and 24 sounds fairly good for this application.

I'm going with the 14-50 socket. after talking to tech people at Tesla, they just advised to manually set the charge rate ( and check to make sure it's the same before each charging session). 14-50 adapter ordered and shipped. Hope the car has a cable when it arrives ( ordered feb10, supposed to arrive end of August. I'd order a cable but they're out of stock....

 

[Rocky_H]

after talking to tech people at Tesla, they just advised to manually set the charge rate

Under what possible rationale? Like seriously, I can't even fathom what reason they could have. If you have a limit of 20A that you need to stay within, it is crazy and irresponsible to put in a 40 or 50A circuit with a 14-50 receptacle, and I can't think of any reason they would have to recommend that. Seriously, Tesla personnel have given some really ridiculously wrong information in the past. And who are "tech people"? I wouldn't really take car salespeople's advice for home electrical wiring questions. You shouldn't necessarily take random internet strangers' advice either, but we have been doing this for a lot of years, and you will notice that we are all agreeing that this is definitely the wrong thing to do.

( and check to make sure it's the same before each charging session).

That is EXACTLY why it is not the right thing to do! It's not reliable, so it creates that questionable situation where you have to double check it every time to make sure it's not reverting back to some higher amount of amps you don't want. This needs to be a lower level circuit that's permanently configured that way, so you don't have to check it every time.

 

[relaxjim]

Under what possible rationale? Like seriously, I can't even fathom what reason they could have. If you have a limit of 20A that you need to stay within, it is crazy and irresponsible to put in a 40 or 50A circuit with a 14-50 receptacle, and I can't think of any reason they would have to recommend that. Seriously, Tesla personnel have given some really ridiculously wrong information in the past. And who are "tech people"? I wouldn't really take car salespeople's advice for home electrical wiring questions. You shouldn't necessarily take random internet strangers' advice either, but we have been doing this for a lot of years, and you will notice that we are all agreeing that this is definitely the wrong thing to do.


That is EXACTLY why it is not the right thing to do! It's not reliable, so it creates that questionable situation where you have to double check it every time to make sure it's not reverting back to some higher amount of amps you don't want. This needs to be a lower level circuit that's permanently configured that way, so you don't have to check it every time.

listen I really appreciate everyone's input. My electrician has dome multiple "off grid" Tesla hookups here on the big island. Living solar/battery has challenges and I've learned to be careful. In 10 years he hasn't steered me wrong . If I later upgrade with more batteries I won't need to upgrade the circuit/socket. I am going to double check it before each charging session. I'm retired, not a big deal . Mahalo everyone!