Question for the more knowledgeable electricity people!

[PeeCee]

So I'm taking my car to a friend's cottage who of course doesn't have an EV Charging Outlet.

However, he does have some RV Plugs.

So I googled around and I found this adapter:
Miady 30A Male to 50A Female 18" RV Dogbone Electrical Adapter with Easy Unplug Design (STW 10/3 Cord)

https://www.amazon.com/Miady-Female...jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==

So my intention was to basically use the Ford Charger that comes with the car, plug that into this extension and then plug the extension into the RV plug so I can at least charge at 30 Amps instead of a normal house plug which is closer to 15 amps.

Is this something that is doable? Someone told me to not do it, as the Ford Charger is made to take in 240v, not 110v and this could cause issues to either the charger or the car. I'd would like to get a second opinion.

In my mind, if I can plut it in a normal 110v with the other adapter that comes with the Ford Charger, I don't see why using the other plug would not work. And also in my mind, if I use something that can take 240v, but only 110v goes through, shouldn't it mean it would work?Just like when you charge your vehicle, if it cantake up 50 amps, but if I feed it only 10 amps, it won't break anything..

Anyways, yeah, looking for more opinions to know if I should avoid doing this or not if it should be fine.

Thanks!

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[macchiaz-o]

No this won't be safe and won't work.

When you use the mobile EVSE's 240V 50A connector, the vehicle will attempt to pull 32 amps of current through your 30 amp circuit.

This should cause your circuit breaker to trip and open the circuit.

If your breaker fails to do this, the circuit's wiring or outlet may overheat, melt, and potentially start a fire.

When you plug in the 120V 15 amp connector, the mobile EVSE reconfigures itself to report an 8-12A maximum to the vehicle instead of 32A.

To use your 30A circuit as is, you'll need a different EVSE with the correct plug and a safe limit of up to 24A of charging current.

 

[PeeCee]

No this won't be safe and won't work.

When you use the mobile EVSE's 240V 50A connector, the vehicle will attempt to pull 32 amps of current through your 30 amp circuit.

This should cause your circuit breaker to trip and open the circuit.

If your breaker fails to do this, the circuit's wiring or outlet may overheat, melt, and potentially start a fire.

When you plug in the 120V 15 amp connector, the mobile EVSE reconfigures itself to report an 8-12A maximum to the vehicle instead of 32A.

To use your 30A circuit as is, you'll need a different EVSE with the correct plug and a safe limit of up to 24A of charging current.

Okay! Thanks for the detailed explanation I will not do it.

 

[PeeCee]

No this won't be safe and won't work.

When you use the mobile EVSE's 240V 50A connector, the vehicle will attempt to pull 32 amps of current through your 30 amp circuit.

This should cause your circuit breaker to trip and open the circuit.

If your breaker fails to do this, the circuit's wiring or outlet may overheat, melt, and potentially start a fire.

When you plug in the 120V 15 amp connector, the mobile EVSE reconfigures itself to report an 8-12A maximum to the vehicle instead of 32A.

To use your 30A circuit as is, you'll need a different EVSE with the correct plug and a safe limit of up to 24A of charging current.

So just out of curiosity, would we know why some people have had success with Tesla's and Nissan Leaf's doing this?

https://www.evseadapters.com/produc...X7ksdNRcJT3V3FZzDArPLa9LfLu3oi3UUlv2FSUD_UXOw

Is there a way for us to tell the Ford EVSE to use less amps?

This guy did it with his Tesla:

 

[ocdxfv]

So just out of curiosity, would we know why some people have had success with Tesla's and Nissan Leaf's doing this?

https://www.evseadapters.com/produc...X7ksdNRcJT3V3FZzDArPLa9LfLu3oi3UUlv2FSUD_UXOw

Is there a way for us to tell the Ford EVSE to use less amps?

This guy did it with his Tesla:

One workaround (which is potentially dangerous but it works) is to make a cable using the appropriate 240v male plug on one end, and a 120v female on the other end. Wire the 240v ground to the 120v ground, one hot to the 120v hot and the other hot to the 120v neutral. You will have an outlet that looks like a standard 120v, but delivers 240 volts, which would be catastrophic if someone were to plug a 120v appliance into it! However, you can now plug the 120v Ford factory charger cable into it and it will charge your car at 240v, 12amps. I know some people will freakout at this suggestion, but it does work. I've used it with my Bolt EV and I tested it on the Ford charger and it does indeed work. If you want some photos, I'd be happy to post them.

 

[methorian]

So just out of curiosity, would we know why some people have had success with Tesla's and Nissan Leaf's doing this?

https://www.evseadapters.com/produc...X7ksdNRcJT3V3FZzDArPLa9LfLu3oi3UUlv2FSUD_UXOw

Is there a way for us to tell the Ford EVSE to use less amps?

This guy did it with his Tesla:

We cannot tell the Mach-E or the mobile EVSE to request less than Max amps for whatever plug you have inserted, so that won't work for us (yet, at least).

Your only option is to get a different EVSE that either allows configuring it's max amperage, or has a lower max amperage standard (if you want to use a 30A circuit).

 

[PeeCee]

So according to this article, the EVSE from Ford should be smart enough to know what Amps that's going through and adjust itself:

https://electrek.co/2019/11/18/ford-mustang-mach-e-home-charging-on-par-with-tesla/

Quote : "

• Supports everything from 120V-8A to 240V-32A and in between, just like Tesla’s UMC. It’s smart enough to detect whatever the outlet is offering.

So technically, even if I put it in a 240v -> 110v 30Amps, the EVSE just like Tesla's should be able to adjust the Amps use pull it only what is available and not necessarly force it to get 50 Amps through a 30amp connection.

 

[CHeil402]

So according to this article, the EVSE from Ford should be smart enough to know what Amps that's going through and adjust itself:

https://electrek.co/2019/11/18/ford-mustang-mach-e-home-charging-on-par-with-tesla/

Quote : "

• Supports everything from 120V-8A to 240V-32A and in between, just like Tesla’s UMC. It’s smart enough to detect whatever the outlet is offering.

So technically, even if I put it in a 240v -> 110v 30Amps, the EVSE just like Tesla's should be able to adjust the Amps use pull it only what is available and not necessarly force it to get 50 Amps through a 30amp connection.

I've answered some of your questions in another thread. But here's the long and short...

https://www.macheforum.com/site/threads/ask-an-electrical-engineer.4307/post-130088

The article you linked to is incorrect in how the Ford Mobile Charger works (at least from any Ford documentation that I've seen). The Ford Mobile Charger (the one that comes with the car) has two options which are automatically set based on which connector (that it comes with) you use. If you connect the NEMA 5-15 plug (120 V outlet), it will pull 120 V / 12 A (1.44 kW). If you connect the NEMA 14-50 plug (240 V outlet), it will pull 240 V / 30 A (7.2 kW).

Regarding the EVSE, the way that they work is that when connected, the EVSE tells the car what it's maximum current supported is. Then the car will ask for the maximum between what it can accept and what the EVSE can supply. The EVSE does not (and cannot) know what the circuit breaker behind it is rated for. If you use the adapter in your OP, it will be pulling 30 A in a 30 A rated circuit and either trip the breaker (best case scenario) or not trip the breaker but exceed the current carrying capacity of the wiring and cause an unsafe condition. Per the electrical code, you cannot pull more than 80% of what the rated circuit breaker is listed for.

Long story short, since the MME doesn't allow you to set the max charge rate, you'll need to purchase an EVSE that does. For example, the Grizzl-e has DIP switches to allow you to choose what the EVSE tells the car is it's maximum supported supply current. If you have a 30 A circuit breaker (regardless of what plug / adapter you're using, and assuming the cabling and outlet are actually rated for 30 A) then the most you can pull is 80% of that 30 A or 24 A.

UPDATE: Based on the video you posted about a Telsa UMC working on that plug is because the Tesla UMC comes with a kit for a multitude of plugs. Each plug (if installed to code) already contains enough information for the EVSE to know what it's max current is. So in the video, using the NEMA TT-30 plug, the UMC was able to know that the circuit was rated for 30 A and therefore could draw the 24 A you see in the video. Just like how the Ford Mobile Charger works with it's two plug options compared to Tesla's larger set. Hopefully Ford eventually offers more plug options.

Feel free to reach out with any follow up questions! And happy travels.

 

[CHeil402]

One workaround (which is potentially dangerous but it works) is to make a cable using the appropriate 240v male plug on one end, and a 120v female on the other end. Wire the 240v ground to the 120v ground, one hot to the 120v hot and the other hot to the 120v neutral. You will have an outlet that looks like a standard 120v, but delivers 240 volts, which would be catastrophic if someone were to plug a 120v appliance into it! However, you can now plug the 120v Ford factory charger cable into it and it will charge your car at 240v, 12amps. I know some people will freakout at this suggestion, but it does work. I've used it with my Bolt EV and I tested it on the Ford charger and it does indeed work. If you want some photos, I'd be happy to post them.

Works... yes.
Safe... no.
Waives your insurance rights if you start a fire... yes.

There are a lot ways to get things to work, but that doesn't mean you should. Safety requirements exist for a reason. I'd rather charge my car slower than burn my house down. If you're comfortable doing it knowing the risk, go ahead, but you should fully understand what you're doing and anyone considering following the suggestion should as well.

 

[PeeCee]

Works... yes.
Safe... no.
Waives your insurance rights if you start a fire... yes.

There are a lot ways to get things to work, but that doesn't mean you should. Safety requirements exist for a reason. I'd rather charge my car slower than burn my house down. If you're comfortable doing it knowing the risk, go ahead, but you should fully understand what you're doing and anyone considering following the suggestion should as well.

Oh yeah, same here! I'm definetly going to plug it in the 110v adapter at the cottage I'm going, not going to take chances with my car and my friend's cottage

However, I like to understand topics and dig deeper. I saw a video where the Tesla's UMC was able to auto adjust to 24A, I find it strange that Ford can't. I mean, I can understand if they decided to go a cheap way and just support 2 options - just a shame that Tesla's "portable" EVSE is capable of adapting to the Amps that's coming out and Ford cannot

 

[CHeil402]

Oh yeah, same here! I'm definetly going to plug it in the 110v adapter at the cottage I'm going, not going to take chances with my car and my friend's cottage

However, I like to understand topics and dig deeper. I saw a video where the Tesla's UMC was able to auto adjust to 24A, I find it strange that Ford can't. I mean, I can understand if they decided to go a cheap way and just support 2 options - just a shame that Tesla's "portable" EVSE is capable of adapting to the Amps that's coming out and Ford cannot

See my update to my original post, the Tesla UMC auto-adjusts in the same way as the Ford Mobile Charger, it just has more plug options...

UPDATE: Based on the video you posted about a Telsa UMC working on that plug is because the Tesla UMC comes with a kit for a multitude of plugs. Each plug (if installed to code) already contains enough information for the EVSE to know what it's max current is. So in the video, using the NEMA TT-30 plug, the UMC was able to know that the circuit was rated for 30 A and therefore could draw the 24 A you see in the video. Just like how the Ford Mobile Charger works with it's two plug options compared to Tesla's larger set. Hopefully Ford eventually offers more plug options.

 

[PeeCee]

See my update to my original post, the Tesla UMC auto-adjusts in the same way as the Ford Mobile Charger, it just has more plug options...

UPDATE: Based on the video you posted about a Telsa UMC working on that plug is because the Tesla UMC comes with a kit for a multitude of plugs. Each plug (if installed to code) already contains enough information for the EVSE to know what it's max current is. So in the video, using the NEMA TT-30 plug, the UMC was able to know that the circuit was rated for 30 A and therefore could draw the 24 A you see in the video. Just like how the Ford Mobile Charger works with it's two plug options compared to Tesla's larger set. Hopefully Ford eventually offers more plug options.

Actually, the guy uses an adapter from a 3rd party seller (link posted in one of my replies I think) and plugged their EVSE into the 3rd party adapter and that adapter was plugged in the NEMA TT-30 plug. The site where that plug was bought also has a version for the NEMA 14-50.

It wasn't a Tesla adapter.

 

[db4z]

So just out of curiosity, would we know why some people have had success with Tesla's and Nissan Leaf's doing this?

https://www.evseadapters.com/produc...X7ksdNRcJT3V3FZzDArPLa9LfLu3oi3UUlv2FSUD_UXOw

Is there a way for us to tell the Ford EVSE to use less amps?

This guy did it with his Tesla:

Another reason some people may have had success with the Nissan Leaf is it appears their maximum on-board charger is 6.6kW, or 27.5A at 240V, which might not trip a 30A breaker. However, as other people have pointed out code states for sustained loads you should not exceed 80% of the breaker. The Mach E I think will pull up to 48A (or the maximum of the EVSE).

The safest way to do this is to buy an EVSE with a maximum current draw of 24A designed for a 30A outlet. I've seen some that are adjustable but they seem pretty rare as I would ideally like one mobile charger than can run at either 24A for a 30A outlet/breaker and 40A for a 50A outlet/breaker.

 

[CHeil402]

Actually, the guy uses an adapter from a 3rd party seller (link posted in one of my replies I think) and plugged their EVSE into the 3rd party adapter and that adapter was plugged in the NEMA TT-30 plug. The site where that plug was bought also has a version for the NEMA 14-50.

It wasn't a Tesla adapter.

Tesla's cars also allow you to set a current limit car-side (which the MME does not as of now). That would be a nice add-on for a future OTA. Also, the Tesla's screen showed it was charging at 120 V not 240 V and he never shows what plug the UMC was using... so who knows.

 

[PeeCee]

Another reason some people may have had success with the Nissan Leaf is it appears their maximum on-board charger is 6.6kW, or 27.5A at 240V, which might not trip a 30A breaker. However, as other people have pointed out code states for sustained loads you should not exceed 80% of the breaker. The Mach E I think will pull up to 48A (or the maximum of the EVSE).

The safest way to do this is to buy an EVSE with a maximum current draw of 24A designed for a 30A outlet. I've seen some that are adjustable but they seem pretty rare as I would ideally like one mobile charger than can run at either 24A for a 30A outlet/breaker and 40A for a 50A outlet/breaker.

Yeah, just that this is a 1 time use And not sure I want to buy such a EVSE for a one time use or drag one around. If an adapter for 40$ could have worked, then that would have made my day and wouldn't be too big to cary around in those rare occasions I could potentially need one.

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