NEMA14-50: How much current can you pull?

[vfx]

By George, I believe you got it!
:tongue:


Here is another:
http://www.adventurerv.net/4prong-generator-adapter-p-7224.html
http://www.rvtoast.com/4prong-generator-adapter-p-7224.html

 

[Tdave]

If I have an electrician wire a 14-50 outlet in my garage such that I could safely draw up to 50 amps (let's say 48 amps) with the proper guage wire and a sufficiently high breaker at the panel, can I tell the Tesla to draw 48 amps from that outlet? (I'll be using a Foundry charge connector if that matters, but I'd hope it wouldn't matter).

 

[TEG]

I think the max you should ever draw from a NEMA14-50 is 40amps.
The "80% rule" says don't pull more than 80% of rated capacity continuously.

So, using the Roadster Foundry adapter's NEMA14-50 plug you should have a 50amp circuit breaker behind the NEMA14-50 and use at least 6 gauge copper wire in the panel. (For wire gauge, lower number means more current, so "at least" means #6 or lower #). Anyways, a licensed electrician should know what to do. I am not one, so I just offer suggestions based on personal observations.

 

[Tdave]

Would the Tesla even allow me to draw more than 40 amps? Could I even set it to draw 48 amps?

 

[TEG]

I am not totally sure about that, but I think the Roadster Foundry box would tell the Roadster "up to 40 amps". It could (in theory) be reprogrammed to permit higher, but that wouldn't be appropriate for a NEMA14-50.

If you want to charge with more than 40amps, I think the HPC is your only option.

 

[Tdave]

If you want to charge with more than 40amps, I think the HPC is your only option.

This is my working assumption. I was just wondering whether: Since there's that trick to get the car to draw 16 amps from a standard 12V outlet that's only rated for 15 amps, I thought something similar might exist for the 14-50 outlet.

 

[donauker]

This is my working assumption. I was just wondering whether: Since there's that trick to get the car to draw 16 amps from a standard 12V outlet that's only rated for 15 amps, I thought something similar might exist for the 14-50 outlet.

There is nothing available to the owner to go higher than the pilot signal from the connector. The car defaults to 12 amps and allows an override to 15 amps (by selecting 16 amps) when there is no pilot signal as with the MC120.

 

[Tdave]

There is nothing available to the owner to go higher than the pilot signal from the connector. The car defaults to 12 amps and allows an override to 15 amps (by selecting 16 amps) when there is no pilot signal as with the MC120.

Got it. That makes sense. Thanks.

 

[TEG]

This is my working assumption. I was just wondering whether: Since there's that trick to get the car to draw 16 amps from a standard 12V outlet that's only rated for 15 amps, I thought something similar might exist for the 14-50 outlet.

I think you meant 120V, not 12V... And no, you shouldn't try to get 16amps from a socket rated for 15. The 16amp setting would be for NEMA 5-20 that look like this:

So the MC120 doesn't come with a NEMA5-20 plug head like that, but can still plug into one of those 5-20 sockets (notice how the socket is T-shaped so it can accommodate either type of plug). So that 16amp setting would really only be if you plugged something like the MC120 into a proper NEMA5-20 socket.

There is nothing like that for the NEMA14-50.

There is such a thing as a NEMA14-60, but I haven't seen anyone use that for EV applications.

That NEMA 14-60 socket is unusual / rare enough that I don't think anyone is bothering to support it for EV charging.

 

[TEG]

If you plugged a MC120 into a NEMA 5-15 socket, and told the Roadster to pull 16 amps it might work (for a while at least). There might be a 20 amp breaker behind it, but the wiring and actual physical socket may not be rated for 15+ amps sustained, so technically I think you shouldn't use the 16amp setting unless you actually found a 5-20 socket. You don't want to start a fire, or burn out the wiring behind the plug.

 

[vfx]

If you plugged a MC120 into a NEMA 5-15 socket, and told the Roadster to pull 16 amps it might work (for a while at least). There might be a 20 amp breaker behind it, but the wiring and actual physical socket may not be rated for 15+ amps sustained, so technically I think you shouldn't use the 16amp setting unless you actually found a 5-20 socket. You don't want to start a fire, or burn out the wiring behind the plug.

Tried the VDS 16 amp setting to pull 15 amps instead of 12 amps at 120V trick last night.

At 10:30PM had 61 ideal miles. Then at 10:20 AM, 159 ideal miles but there was also an an error message about charging. The circuit was fine with no breaker blown, not even on the plug strip. The sprinkler system is on that line and kicks on at 11PM so at first I thought that might have done it but it's only on a 12V wall wart transformer. Besides, at 12amps we were getting 3.5 Miles Per Hour charge. Last night's 12 hours of charging and 98 mile gain makes 10 ish MPH so I figure the error must have just happened as I walked out.

 

[TEG]

In case anyone missed it, one of the big differences between NEMA 14-50s and NEMA 5-15s is that the 240V NEMA 14-50 tends to have one socket per breaker, but a household 120V NEMA 5-15 may have many outlets on the same breaker. In fact, a typical NEMA 5-15 has two sockets on the outlet so you are encouraged to plug multiple things into it. If you tell your MC120 to take 16amps from one socket you may already be pushing the wiring, and then if you fire up other things on the same circuit you could really get close to overloading things.

You can do the same thing with a vacuum and a microwave, or a hair dryer and an air conditioner. Multiple items that try to use the max rated capacity of one socket aren't meant to be run at the same time. So you are expected to know the capacity of your circuits and add up all the loads and make sure you don't overload. This is basic household wiring stuff, but people frequently plug in power strips and keep adding things until one day they find the limits of their wiring. Hopefully it is the circuit breaker that lets them know and not something else.

 

[vfx]

So you are expected to know the capacity of your circuits and add up all the loads and make sure you don't overload.

Just to clarify my setup. I know every plug on that circuit and the one that shares the plugstrip with the MC120 only has devices that are normally off -I just don't want to have to plug them in every time I want to use them.

Notably there is a small compressor, a tiny motor that runs at 6PM for 15 seconds and the aformentioned night sprinklers. I already know that the compressor is the only thing that can be running on the circuit at one time (it is switched off). Now that the car is on that line I know that nothing else can run on it but that. The first week was to test at 12A if the few solenoids in the sprinklers would be too much. And if the little motor would be OK as well. With the car at 15A the little motor ran a few minutes ago just fine. Will check again tonight on the sprinklers.

The math seems all wrong at this point. A 12 to 15 amp jump should not get a 3.5 to 10 MPHCharge increase.

 

[TEG]

The math seems all wrong at this point. A 12 to 15 amp jump should not get a 3.5 to 10 MPHCharge increase.

Yeah - whats up with that?

Perhaps this MC120 stuff should get moved to a different thread at some point?

 

[ChargeIt!]

The math seems all wrong at this point. A 12 to 15 amp jump should not get a 3.5 to 10 MPHCharge increase.

Yes, the math is wrong. What was the exact error message ... but you probably didn't write it down :frown:

Have you cycled the "ignition" yet ... and check again what is reported for range ?

 

[vfx]

Yes, the math is wrong. What was the exact error message ... but you probably didn't write it down :frown:

Have you cycled the "ignition" yet ... and check again what is reported for range ?

The message was quite short. Five words and two of them were charging error. I'll note it exactly if it happens again.

To clear the screen I pulled the connector and closed the charge door.

Last night's test was entirely successful. Charged from 3:00 PM yesterday though the little motor run at 6PM and I went out at 12:AM to see everything humming away while the sprinklers were running. This morning there was no Charge Error (yet).


At 3PM there were 103 Ideal miles.
At 12AM there were 144 Ideal miles
At 7AM there are 178 Ideal miles

That a 4.5 segment and a 4.8 MPHC segment. -better math there.

Nothing is hot to the touch and all seems well so I will gladly take the extra 10 to 20 miles per night.

(sorry to get so far off topic. I agree a "MC120 Connector" thread would be more appro)

 

[folsomev]

Hey, does anyone know the vendor for those yellow NEMA 14-50 plugs with the safety handle molded into the plug housing?

Thanks.

J.C. Whitney....

EVNut has a link to it at the top of this page. The link is labeled "Sweet 14-50 Plug with handle."
Charger Adapters

 

[TEG]

I think you missed the followup replies.
I bought one from Amazon.com (search on "Camco 55255").
Amazon.com: Camco 55255 RV 50 Amp PowerGrip Replacement Plug: Automotive

 

[ra-san]

Tried the VDS 16 amp setting to pull 15 amps instead of 12 amps at 120V trick last night.

At 10:30PM had 61 ideal miles. Then at 10:20 AM, 159 ideal miles but there was also an an error message about charging. The circuit was fine with no breaker blown, not even on the plug strip. The sprinkler system is on that line and kicks on at 11PM so at first I thought that might have done it but it's only on a 12V wall wart transformer. Besides, at 12amps we were getting 3.5 Miles Per Hour charge. Last night's 12 hours of charging and 98 mile gain makes 10 ish MPH so I figure the error must have just happened as I walked out.

I'll bet a miles worth of electricity that it was an error screen that said something to the effect of:
Charging Error
Check Supply Power
ID 1065 Data: 0x00000010

If so, my understanding is that it is a low voltage warning. Check the voltage readout on the VDC after it gets going, and with anything else running that may have been running when the error occurred. Far as I can tell, it's a somewhat innocuous error. At least Tesla didn't seem too concerned when I asked about it, in terms of damage to the car or anything. It'll still charge. I had the same issue with one circuit in my garage. It would pull from 110 ish V down to 99-101 under load, varying by whether I had it set to 12Amp or 15Amp. I had to search around for a different one, which reads 118V no load, and 110+ under 12 or 15 Amp load.

A separate MC120 thread would be great. I don't get that number of MPH charging from mine. I get more like 2.5 to 3.6 ideal range miles per hour of charging. I'm Keeping a log though to track it over time, since the ideal range number does vary - even had it go a couple miles down *while* charging between one hour mark and the next reading an hour or so later.

 

[vfx]

I'll bet a miles worth of electricity that it was an error screen that said...

If so, my understanding is that it is a low voltage warning. Check the voltage readout on the VDC after it gets going, and with anything else running that may have been running when the error occurred. Far as I can tell, it's a somewhat innocuous error. At least Tesla didn't seem too concerned when I asked about it, in terms of damage to the car or anything. It'll still charge. I had the same issue with one circuit in my garage. It would pull from 110 ish V down to 99-101 under load, varying by whether I had it set to 12Amp or 15Amp. I had to search around for a different one, which reads 118V no load, and 110+ under 12 or 15 Amp load.

A separate MC120 thread would be great. I don't get that number of MPH charging from mine. I get more like 2.5 to 3.6 ideal range miles per hour of charging. I'm Keeping a log though to track it over time, since the ideal range number does vary - even had it go a couple miles down *while* charging between one hour mark and the next reading an hour or so later.

Agreed on the MC120 thread.

Well I only got it that screen once. It's been fine since. Good thing because I've only got the one circuit to choose from. I've been logging as well.

This enlightening post appeared today on the TMO blog.

I have encountered some cases where the car showed a range of for example 240 miles and after driving 30 miles showed a range of only 150 miles. In another case the range showed over 200 miles and after sitting for 2 hours the range dropped by 60 miles. After sending my logs to Tesla they indicated that everything is normal, this is due to the nature of Lithium batteries. To get an accurate range before starting on a long trip the charging should be off for at least 10 minutes (either fully charged or unplugged) with the car off (key out). When the key is inserted the range displayed will be much more accurate. It also helps if the battery is fully charged because that is a reference point for calculating the range. Also the accuracy of the range if the battery doesn't reach full charge, is better at higher current i.e. the 240v at 30 amp is better then the 120V.
Posted ... Today at 10:57 AM.

I have been tangentelly aware of this but not been logging with the proper "scrubbing" of the readout and I realize I need a bigger sampling but in the end it is what it is. I just want to make sure there is no other problem like another owner had.