RV & Off the Beaten Track Charging

Jan King

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#1
I have learned the following in preparation for a trip to Newfoundland in our Model 3 long range. We need to be able to charge from as many sources as possible, but want to keep the number of cables and adapters down. The long range car can take 48A at 240V, the UMC gen 2 can charge at 32A. The UMC uses resistors in the supplied adapters to set the charging rate so its not easy to make an adapter on your own to fit the UMC socket, so its easier to set the charge rate limit on the car screen.

I have chosen to use a 30A, 50 foot RV extension cord. A 50Amp cord would be heavier and more expensive. With the Gen2 UMC the car can only take 32A max anyway. If you do buy a 30A cords or adapters, do not get ones with lights as they will be designed only for 120V not 240V. RV parks have 50A outlets (240VAC) of which only about 40A should be used and 30A outlets (120VAC) of which only about 24A should be used.

If you buy a normal 50A male to 30A female RV adapter you will only get 120VAC (one hot and one neutral) and the car will not charge with the Tesla supplied 50A UMC adapter (as the hot and neutral are not connected to the 2 hot pins on the 50A connector that the 14-50UMC is looking for). If you buy a special 50A male to 30A female adapter marked for Tesla (amazon or EVSE chargers) it will work as they will be wired to the 2 hot pins but this adapter can't be used for RVs as it will be twice the voltage the RV is expecting.

Oven outlets (NEMA 14-50) and dryer outlets (NEMA 14-30) are the same shape and size except for the neutral pin (flat blade in the centre). To save on connectors since the 14-50 UMC adapter does not use the neutral pin, removing it allows a male plug 50A to fit in both Oven and Dryer sockets.

Lowes sells the male 14-50 replacement head plug which has two different neutral pins which can be switched for ovens (straight neutral) or dryers (L shape neutral) or left off for less than $20.

I will be setting 24A max charge rate using the extension cord which should give about 37km/hour or 23 miles/hour at 240VAC and half this at 120VAC.

Here are two non standard adapters. The first converts the 240VAC from a oven or dryer to NEMA 14-30, for attachment to a 14-30 extension cord. The second converts it back to 14-50 for the UMC.
img_0303-jpg.11307

Then also regular adapters can be purchased for use with 120VAC. So only one extension cord can be carried.
img_0304-jpg.11308

I hope this information helps.

On Amazon
Conntek 14364 RV 30-Amp STW 10/3 Durable Extension Cord with Straight Blade, 50-Feet
Camco 55353 50 AMP Female Replacement Receptacle
Camco 55175 RV 18-Inch Power Grip Dogbone Electrical Adapter with Handle
 
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garsh

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#2
I have chosen to use a 30A, 50 foot RV extension cord as a 50Amp cord would be heavier, more expensive as the car can only take 32A max anyway.
Just to clarify: The car itself is capable of accepting 48 amps.
The Mobile Connector that's included with the car can only supply 32 amps max.
The older Corded Mobile Connector is capable of delivering 40 amps.
 

belanger

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#4
Tesla charger w/ 14-50 adapter will use up to 32A from the circuit, on a 30A 50' cable and adapter. You should put a disclaimer in case someone follows your suggestion and cause a fire.
 

garsh

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#6
Tesla charger w/ 14-50 adapter will use up to 32A from the circuit, on a 30A 50' cable and adapter. You should put a disclaimer in case someone follows your suggestion and cause a fire.
It won't cause a fire. It will just cause a breaker to trip.
 

garsh

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#9
True if the breaker isn't faulty. Just like there are recalls on cars, etc - there are recalls on breakers as well so I have to repeat fires could happen.
LOL, ok, if you have a bad breaker, then a fire could happen. But that's easy enough to test - try pulling 32 amps on the circuit and confirm that the breaker trips within a reasonable amount of time. If it doesn't, then replace the breaker.
 

Jan King

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#10
About pulling too much current. I suggest in the article that you should only pull 24A from a 30A outlet which you need to do by lowering the current in the car before plugging in. About pulling 32A from a 50A outlet, the 10AWG wire from the extension cord seems to be thicker than the wire in the mobile UMC (I do not have any data on the size of the UMC wire). I have noticed that the UMC wire is warmer than the 30A extension cord wire so in my opinion the UMC is the weakest link. I did not rate it to 32A Tesla did. I understand your concern but in practice it is not an issue in this case.
 

Jeffoag

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#11
I have learned the following in preparation for a trip to Newfoundland in our Model 3 long range. We need to be able to charge from as many sources as possible, but want to keep the number of cables and adapters down. The long range car can take 48A at 240V, the UMC gen 2 can charge at 32A. The UMC uses resistors in the supplied adapters to set the charging rate so its not easy to make an adapter on your own to fit the UMC socket, so its easier to set the charge rate limit on the car screen.

I have chosen to use a 30A, 50 foot RV extension cord. A 50Amp cord would be heavier and more expensive. With the Gen2 UMC the car can only take 32A max anyway. If you do buy a 30A cords or adapters, do not get ones with lights as they will be designed only for 120V not 240V. RV parks have 50A outlets (240VAC) of which only about 40A should be used and 30A outlets (120VAC) of which only about 24A should be used.

If you buy a normal 50A male to 30A female RV adapter you will only get 120VAC (one hot and one neutral) and the car will not charge with the Tesla supplied 50A UMC adapter (as the hot and neutral are not connected to the 2 hot pins on the 50A connector that the 14-50UMC is looking for). If you buy a special 50A male to 30A female adapter marked for Tesla (amazon or EVSE chargers) it will work as they will be wired to the 2 hot pins but this adapter can't be used for RVs as it will be twice the voltage the RV is expecting.

Oven outlets (NEMA 14-50) and dryer outlets (NEMA 14-30) are the same shape and size except for the neutral pin (flat blade in the centre). To save on connectors since the 14-50 UMC adapter does not use the neutral pin, removing it allows a male plug 50A to fit in both Oven and Dryer sockets.

Lowes sells the male 14-50 replacement head plug which has two different neutral pins which can be switched for ovens (straight neutral) or dryers (L shape neutral) or left off for less than $20.

I will be setting 24A max charge rate using the extension cord which should give about 37km/hour or 23 miles/hour at 240VAC and half this at 120VAC.

Here are two non standard adapters. The first converts the 240VAC from a oven or dryer to NEMA 14-30, for attachment to a 14-30 extension cord. The second converts it back to 14-50 for the UMC.
View attachment 11307
Then also regular adapters can be purchased for use with 120VAC. So only one extension cord can be carried.
View attachment 11308
I hope this information helps.

On Amazon
Conntek 14364 RV 30-Amp STW 10/3 Durable Extension Cord with Straight Blade, 50-Feet
Camco 55353 50 AMP Female Replacement Receptacle
Camco 55175 RV 18-Inch Power Grip Dogbone Electrical Adapter with Handle
Hi, I really like you set up: one extension cord with few adapters. Questions:
1. Where did you get the 2 non-standard adapters: 240v dryer to NEMA 14-30, and 14-30 to 14-50?
2. Is the other adapter NEMA 5-15 (regular home outlet) to 14-30? Where did you get it? (On amazon, lots of NEMA 5-15 to 14-50, but no 5-15 to 14-30).
3. What's the Camco 55353 50 AMP Female Replacement Receptacle for? (I guess you can cut one end of the 14-30 cable and wire it to this 14-50 receptacle? But I am not so sure..)
4. The cable you listed at the end (Conntek 14364 RV 30-Amp) has TT-30 plug, not 10-30, and it is only for 120V, not 240. But you said you want to cable for 240V. Am I confused?
 
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Bibs

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#12
On a non-electrical side note...

A lot of RV parks have cabins for rent, as well. We grabbed 32A overnight and rented a cabin at an RV spot in Upper Michigan... definitely easier than getting two dogs (and us) into the 2nd or 3rd story of a hotel. Nice serene evening sitting on the cabin porch looking at the stars. And we started the next morning with the car ready to roll.
 
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#13
I’m a bit confused. Wouldn’t it be simpler just to get a 50-amp extension (14-50) along with a 15-amp Female/50-amp Male adapter? Would this not work?

 

garsh

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#14
I’m a bit confused. Wouldn’t it be simpler just to get a 50-amp extension (14-50) along with a 15-amp Female/50-amp Male adapter? Would this not work?
Yes, it would work, but Jan explains why he didn't go that route:
A 50Amp cord would be heavier and more expensive. With the Gen2 UMC the car can only take 32A max anyway.
50ft-long 14-50 extension cords can get expensive. And they weigh 35-40 lbs, and they're a bit of a pain to roll up and store. Going with a lighter-gauge cable makes a lot of sense given the UMC's inability to charge beyond 32 amps anyhow.

 

garsh

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#15
50ft 30 amp extension cords only weigh about 14 lbs. They're much easier to deal with.

 

Feathermerchant

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#16
And if you're buying a Nema 14-50, you're wasting about 25% weight and $ because Tesla does not use the neutral for anything.
Probably not kosher to make up a Nema 14-50 with no neutral. Would probably be OK to make a 6-50 cord and adapters.
 

Jan King

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#17
Hi, I really like you set up: one extension cord with few adapters. Questions:
1. Where did you get the 2 non-standard adapters: 240v dryer to NEMA 14-30, and 14-30 to 14-50?
2. Is the other adapter NEMA 5-15 (regular home outlet) to 14-30? Where did you get it? (On amazon, lots of NEMA 5-15 to 14-50, but no 5-15 to 14-30).
3. What's the Camco 55353 50 AMP Female Replacement Receptacle for? (I guess you can cut one end of the 14-30 cable and wire it to this 14-50 receptacle? But I am not so sure..)
4. The cable you listed at the end (Conntek 14364 RV 30-Amp) has TT-30 plug, not 10-30, and it is only for 120V, not 240. But you said you want to cable for 240V. Am I confused?
Hi,
1. I made two of the non standard adapters myself. One of them in the photo said it would work for Tesla charging but it was not correctly wired and I had to return it and make it myself. I got one plug from Lowes and put a 30A outlet connector on the other end, but you can also buy them online if you are not familiar with wiring. The main point in wiring is that the neutral wire is not used by the UMC, but the ground and two hots are used.
2. I bought the regular outlet to 30A connector (I think I bought it at Canadian Tire in the RV section of the store) about $20
3. The Camco 55353 outlet was used to convert the connection back from 30A to the 50A connection for the UMC, however you could just cut off the end of the 30A extension cord and install the outlet on the extension cord. I was going to need a 30A to 50A adapter anyway so I did not do this so I would not have to carry the extension cord all the time and could just carry the adapters for more flexibility.
4. The Conntek 14364 RV 30-Amp is rated for 30 Amps, but I run both 240V and 120V through it. Wire is normally rated by amps, the extra volts will not hurt it in this case but you must be careful not to get ones with indicator lights as they would be only able to handle 120VAC. This is the trick I used to save weight and money, to use the same extension cord for both 120VAC and 240VAC compared to the 50A extension cord would also have an extra wire in it that is not used and would be an additional waste of money and weight.
 
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garsh

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#18
Wire is normally rated by amps, the extra volts will not hurt it
Further FYI - the insulation on the wires will have a voltage rating. If you go above that voltage, then it can short/spark from one connector to another, and you'll have a bad day. The voltage rating tends to be much higher than what it will normally be used for.

As an example, here's a regular 120v extension cord. If you go to the page and magnify the image, you'll see that the insulated cable is rated for 300v.
 

Jeffoag

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#19
Hi,
1. I made two of the non standard adapters myself. One of them in the photo said it would work for Tesla charging but it was not correctly wired and I had to return it and make it myself. I got one plug from Lowes and put a 30A outlet connector on the other end, but you can also buy them online if you are not familiar with wiring. The main point in wiring is that the neutral wire is not used by the UMC, but the ground and two hots are used.
2. I bought the regular outlet to 30A connector (I think I bought it at Canadian Tire in the RV section of the store) about $20
3. The Camco 55353 outlet was used to convert the connection back from 30A to the 50A connection for the UMC, however you could just cut off the end of the 30A extension cord and install the outlet on the extension cord. I was going to need a 30A to 50A adapter anyway so I did not do this so I would not have to carry the extension cord all the time and could just carry the adapters for more flexibility.
4. The Conntek 14364 RV 30-Amp is rated for 30 Amps, but I run both 240V and 120V through it. Wire is normally rated by amps, the extra volts will not hurt it in this case but you must be careful not to get ones with indicator lights as they would be only able to handle 120VAC. This is the trick I used to save weight and money, to use the same extension cord for both 120VAC and 240VAC compared to the 50A extension cord would also have an extra wire in it that is not used and would be an additional waste of money and weight.
Thanks for the detailed reply. One more question: it seems that you are treating NEMA 10-30 and TT-30 as the same plug/receptacle. E g., The cable in 4 is actually TT-30, but you are using it as 10-30. Other than the volt difference (120v can 240v), are they physically compatible? That is, can a 10-30P plugs/fits in a TT-30R? And vice versa: can a TT-30P plugs in a 10+30P?
 
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